Atwater City Council
June 22, 2026

Merced County Multi-Jurisdictional Hazard Mitigation Plan Hazard Identification and Risk Assessment
2021-2026 Update Page 4-86
Jurisdiction Geographic
Extent
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
City of Los Banos Limited Likely Limited Medium
City of Merced Significant Likely Limited Medium

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4.2.5 Landslide
Hazard Problem/Description
A landslide is a geologic hazard where the force of gravity combines with other factors to cause earth material to move or slide down an incline. Some landslides move slowly and cause damage gradually, whereas others move so rapidly that they can destroy property and take lives suddenly and unexpectedly.

Slopes with the greatest potential for sliding are between 34 degrees and 37 degrees. Although steep slopes are commonly present where landslides occur, it is not necessary for the slopes to be long.

Debris flows are a mixture of rock fragments, soil, vegetation, water and, in some cases, entrained air that flows downhill as a fluid. Debris flows can range in consistency from that of freshly mixed concrete to running water. Debris flows can be further classified as mudflows and earth flows depending on the ratio of water to soil and rock debris.

Landslide and debris flow problems can be caused by land mismanagement, particularly in mountain, canyon, and coastal regions. In areas burned by forest and brush fires, a lower threshold of precipitation may initiate landslides and debris flows. As human populations expand over more of the land surface, these processes become an increasing concern.

There are predictable relationships between local geology and landslides, rockslides, and debris flows. The downslope movement of earth material, either as a landslide, debris flow, mudslide, or rockslide, is part of the continuous, natural process of erosion. This process, however, can be influenced by a variety of causes that change the stability of the slope. Slope instability may result from natural processes, such as the erosion of the toe of a slope by a stream, or by ground shaking caused by an earthquake. Slopes can also be modified artificially by grading, or by the addition of water or structures to a slope. Development that occurs on a slope can substantially increase the frequency and extent of potential slope stability hazards.

Knowledge of these relationships can improve planning and reduce vulnerability. Slope stability is dependent on many factors and their interrelationships, including rock type, moisture content, slope steepness, and natural or manmade undercutting.

Geographic Area
In Merced County the landscape is largely characterized by the San Joaquin Valley, which is relatively flat and takes up the majority of the central portion of the county. To the eastern edge of the county, lying within the foothills of the Sierra Nevada range, and the western edge, within the Coast Range, there are several geologic formations commonly associated with slope stability problems. Figure 4-19 below provides a summary of landslide hazard potential. As shown in the map, the areas of the county with the greatest potential susceptibility to landslide hazards are in the far southwest of the county, on the western side of Interstate 5. This area is all unincorporated area in the county and is largely rural in character, indicating a lower potential risk to property and infrastructure relative to other counties in California.

Merced County Multi-Jurisdictional Hazard Mitigation Plan Hazard Identification and Risk Assessment
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Figure 4-19 Merced County Deep-Seated Landslide Susceptibility

Merced County Multi-Jurisdictional Hazard Mitigation Plan Hazard Identification and Risk Assessment
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Extent (Magnitude/Severity)
The extent of landslides and debris flow events within the county range from negligible to significant.

Landslides and rockslides can result in the destruction of infrastructure such as water and sewer lines, electrical and telecommunications utilities and drainage where they are present. There is potentially risk to Interstate 5, near the county border with Fresno County. There is limited potential for complete destruction of buildings and death and injury from landslides and debris flow.

Previous Occurrences
There have not been any disaster declarations associated with landslides in Merced County. According to records from the California Department of Conservation’s Geological Survey, there have been no recent records of landslides in Merced County and no active mapping efforts within the county. Several adjacent counties, such as Madera, Mariposa, and Santa Clara, have recent or active landslides which have been recorded. This historic record would indicate that landslides occasionally occur in Merced County, but largely affect undeveloped areas.

Probability of Future Occurrences
Based on historical data which suggests limited risk of landslides, but given the presence of landslide susceptible geology and steep slopes within the planning area, it is safe to assume that landslides may occur in the future, with damaging landslides occurring much less frequently. Landslides are usually a cascading effect of severe weather or a period of extended wet weather that saturates local soils. The probability for more severe and damaging landslides increases during El Niño years or severe winter storms. The potential for debris flows dramatically increases following a wildfire.

Climate Change Considerations
Landslides can result from intense rainfall and runoff events. Projected climate change-associated variance in rainfall events may result in more high-intensity events, which may increase landslide frequency. In addition, the increased potential of wildfire occurrence also escalates the risk of landslide and debris flows in the period following a fire, when slopes lack vegetation to stabilize soils and burned soil surfaces create more rainfall runoff. As climate change affects the length of the wildfire season, it is possible that a higher frequency of large fires may occur into late fall, when conditions remain dry, and then be followed immediately by intense rains early in the winter, as occurred with the Thomas Fire in December 2017 and subsequent Montecito and Carpinteria debris flows in January 2018 in Santa Barbara County (CA SHMP 2018).

Vulnerability Assessment
General Property
Landslides directly damage engineered structures in two general ways: 1) disruption of structural foundations caused by differential movement and deformation of the ground upon which the structure sits, and 2) physical impact of debris moving downslope against structures located in the travel path.

During the 2021 update of this plan, a GIS analysis of exposure to landslide hazard areas was performed.

GIS analysis indicates approximately $317 million of property improvements exposed, which takes into account improved values of properties. Table 4-49 summarizes landslide exposure by jurisdiction. GIS was used to intersect the parcel boundaries with a master address point layer to obtain the number of buildings per parcel. Only parcels with improvement values greater than zero were used in the analysis, this method assumes that improved parcels have a structure of some type.

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Based on this analysis there is a total of 482 improved parcels and 547 buildings potentially within landslide hazard areas. The majority of this exposure is in the western unincorporated county. There is a high level of uncertainty as to the actual risk to these exposed parcels, thus a more specific loss estimation is not provided. A more detailed, site specific analysis would be needed to assess actual risk within the identified parcels.

Table 4-50 Merced County Improved Properties at Risk to Landslide Jurisdiction Improved
Parcel
Count
Total
Building
Count
Improved
Value
Estimated
Content Value
Total Value Population
Atwater 11 11 $3,479,587 $2,831,312 $6,310,899 32
Livingston 1 1 $2,714,360 $1,357,180 $4,071,540 4
Merced 27 42 $4,762,383 $2,381,192 $7,143,575 112
Unincorporated 443 493 $156,446,776 $142,936,749 $299,383,525 322 Total 482 547 $167,403,106 $149,506,432 $316,909,538 470 Source: Dept. of Conservation, California Geological Survey, Merced County Assessor, Wood GIS Analysis Figure 4-20 below further breaks down the numbers of exposed buildings by landslide class, as shown previously in Figure 4-19; the higher the class the greater the susceptibility.

Figure 4-20 Total Building Counts by Landslide Class
People
People could be susceptible if they are caught in a landslide or debris flow, potentially leading to injury or death. There is also a danger to drivers operating vehicles, as rocks and debris can strike vehicles passing through the hazard area or cause dangerous shifts in roadways. The parcel analysis described previously estimated the number of people potentially residing in landslide susceptible areas (470), but it is not likely that landslides will occur without warning and direct impacts to people are suspected to be minimal. 0 100 200 300 400 500 600
Class 3 Building Count
Class 5 Building Count
Class 6 Building Count
Class 7 Building Count
Class 8 Building Count
Class 9 Building Count
Class 10 Building Count
Total Building Count
Total Building Counts by Landslide Class

Merced County Multi-Jurisdictional Hazard Mitigation Plan Hazard Identification and Risk Assessment
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Critical Facilities and Infrastructure
In addition to buildings, utilities and transportation structures are vulnerable to the impact and ground deformation caused by slope failures. They present a particular vulnerability because of their geographic extent and susceptibility to physical distress. Lifelines are generally linear structures that, because of their geographic extent, have a greater chance of being affected by ground failure due to greater hazard exposure.

Extension, bending, and compression caused by ground deformation can break lifelines. Failure of any component along the lifeline can result in failure to deliver service over a large region. Once broken, transmission of the commodity through the lifeline ceases, which can have catastrophic repercussions down the line: loss of power to critical facilities such as hospitals, impaired disposal of sewage, contamination of water supplies, disruption of all forms of transportation, release of flammable fuels, and so on. Therefore, the overall impact of lifeline failures, including secondary failure of systems that depend on lifelines, can be much greater than the impact of individual building failures.

Table 4-50 below summarizes the results of the critical facilities analysis, highlighting the exposure of critical facilities throughout the county to landslide hazards. All of the exposed critical facilities are located in unincorporated areas of the county, largely to the west of Interstate 5.

Table 4-51 Critical Facilities Within the Class 9 Landslide Hazard by FEMA Lifeline Jurisdiction Landslide
Class
Communications Energy
Food,
Water,
Shelter
Hazardous
Material
Health
and
Medical
Safety
and
Security
Transportation Total
Uninc.
9 2 26 - - - - - 28
8 1 48 - - - - - 49
7 - 4 - - - - 46 50
6 1 - - - - - - 1
5 4 80 - - - - 3 87
3 1 - - - - - - 1
Total 9 158 0 0 0 0 49 216
Source: California Geological Survey, HIFLD, Wood GIS Analysis Economy
Economic impacts typically center around transportation routes temporarily closed by debris flow or landslide activity. These roads may be used to transport goods across the county or provide access by visitors and tourists. Depending on the amount of damage, the road may simply need to be cleaned off, or may require some level of reconstruction.

Historic, Cultural, and Natural Resources
As primarily a natural process, landslides and debris flows can have varying impacts to the natural environment; debris flows have the potential to permanently alter the natural landscape.

Future Development
The severity of landslide problems is directly related to the extent of human activity in hazard areas.

Human activities such as property development and road construction can also exacerbate the occurrence of landslides. Future development should take place carefully to prevent landslide damage to property or people. Adverse effects can be mitigated by early recognition and avoiding incompatible land uses in

Merced County Multi-Jurisdictional Hazard Mitigation Plan Hazard Identification and Risk Assessment
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these areas or by corrective engineering. Improving mapping and information on landslide hazards and incorporating this information into the development review process could prevent siting of structures and infrastructure in identified hazard areas. The 2030 General Plan has provisions to address this goal, by prohibiting habitable structures atop unconsolidated landslide debris, discouraging grading and construction on slopes greater than 30%, and enforcing grading standards of the International Building Code.

Risk Summary
The overall significance of landslides in Merced County is low. ● The geologic formations commonly associated with slope stability problems in Merced County, are largely concentrated in the far western and eastern edges of the county, which are also the least populated.
● Effects on people: People are most commonly at risk if they are caught in a landslide or debris flow, including when driving through a hazard area.
● Effects on property: Property loss is rare, but GIS analysis shows there is some property which could be exposed to landslides.
● Effects on economy: Landslides in adjacent counties can disrupt major transportation corridors, possibly affecting the local tourist economy and shipment of goods. ● Effects on critical facilities and infrastructure: Landslides and debris flows can result in the destruction of infrastructure such as water and sewer lines, electrical and telecommunications utilities and drainage. Disrupted transportation routes occur occasionally, usually during heavy rainstorms, and cause considerable inconvenience.
● Related Hazards: Earthquake, Adverse Weather, Wildfire.

Table 4-52 Hazard Risk Summary - Landslides
Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Limited Occasional Limited Low
City of Atwater N/A
City of Dos Palos N/A
City of Gustine N/A
City of Livingston N/A
City of Los Banos N/A
City of Merced N/A

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4.2.6 Severe Weather: General
The climate in the Central Valley is defined generally by hot, dry summers and foggy, rainy winters. Severe weather is generally any destructive weather event, but usually occurs in Merced County as localized thunderstorms that bring heavy rain and strong winds that occur most often during the winter and spring months. The agricultural industry is among the most vulnerable asset to severe weather. Agricultural losses resulting from natural hazards can have dramatic impacts on the economic health of Merced County.

For this plan, adverse weather is broken down as follows:
● Freeze
● Extreme Heat
● Dense Fog
● Heavy Rain
● High Wind/Tornado
The National Oceanic and Atmospheric Administration’s NCEI has been tracking adverse weather since 1950. Their Storm Events Database contains data on the following: all weather events from 1993 to 2017 (except from 6/1993-7/1993); and additional data from the Storm Prediction Center, which includes tornadoes (1950-1992), thunderstorm winds (1955-1992), and hail (1955-1992). This database contains 254 storm events that occurred in Merced County between January 1, 1950, and December 2020. The table below summarizes these events.

Table 4-53 NCEI Hazard Event Reports for Merced County, 1950-2020 Hazard # of Events Property Loss ($) Crop Loss ($) Deaths Injuries Dense Fog* 102 $1,160,00 $0 3 7
Frost/Freeze* 31 $0 $0 0 0
Heavy Rain 23 $2,007,500 $15,660,000 0 0
Strong Wind* 20 $90,800 $513,000 0 0
Funnel Cloud 18 $0 $0 0 0
Tornado 14 $410,000 $50,000 0 1
Heat* 13 $0 $0 0 0
High Wind* 12 $995,000 $2,110,000 0 4
Hail 9 $30,000 $1,233,000 0 4
Lightning 8 $1,000,000 $0 0 1
Thunderstorm Wind 4 $430,000 $3,100,000 0 0
Total 254 $4,963,300 $22,666,000 3 17
Source: NCEI Storm Events Database, www.ncdc.noaa.gov/stormevents/ *Hazards with wide extents reflect larger zones that extend beyond Merced County.

The NCEI table above summarizes adverse weather events that have occurred in Merced County from 1950 to 2020. Only a few of the events actually resulted in state and federal disaster declarations. It is interesting to note that different data sources capture different events during the same time period, and often different information specific to the same events. While the HMPC recognizes these inconsistencies, this data provides value in depicting the County’s “big picture” hazard environment.

Due to size of the County and changes in elevation and climate, weather conditions can vary greatly across the County. The profiles that follow provide information, where possible, from two weather stations in different parts of the County: Merced Municipal Airport Weather Station in the northeastern part of the county (1889-2016) and the Los Banos City weather station in the southwestern part of the county (1906- 2016). The temperature data from these two weather stations are displayed in subsection 4.3.7 below.

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4.2.7 Severe Weather: Extreme Temperatures: Freeze and Extreme Heat Hazard/ Problem Description
Extreme temperature events, both cold and hot, can have severe impacts on human health and mortality, natural ecosystems, and agriculture and other economic sectors.

Freeze
Extreme cold often accompanies a winter storm or is left in its wake. Prolonged exposure to cold can cause frostbite or hypothermia and can be life-threatening. Infants and the elderly are most susceptible.

Pipes may freeze and burst in homes or buildings that are poorly insulated or without heat. Freezing temperatures can cause significant damage to the agricultural industry.

Extreme Heat
Extreme heat events can have severe impacts on human health and mortality, natural ecosystems, the agriculture sector and other economic sectors. According to information provided by FEMA, extreme heat is defined as temperatures that hover 10 degrees or more above the average high temperature for the region and last for several weeks. Heat kills by taxing the human body beyond its abilities, usually from heat stroke. In a normal year, about 175 Americans succumb to the demands of summer heat. According to the NWS, among natural hazards, only the cold of winter—not lightning, hurricanes, tornadoes, floods, or earthquakes—takes a greater toll. As a comparison, in the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation. In the heat wave of 1980, more than 1,250 people died. The 2018 California State Hazard Mitigation Plan (SHMP) notes the 2006 heat wave led to 650 deaths in a 13-day period (Cal OES 2018) and in the past 15 years heat waves have claimed more lives in California than all other declared disaster events combined (California Climate Adaptation Strategy 2018).

Heat disorders generally have to do with a reduction or collapse of the body’s ability to shed heat by circulatory changes and sweating or a chemical (salt) imbalance caused by too much sweating. When heat gain exceeds the level the body can remove, or when the body cannot compensate for fluids and salt lost through perspiration, the temperature of the body’s inner core begins to rise, and heat related illness may develop. The elderly, small children, individuals who work outside, patients with chronic medical conditions, those on prescription medication therapy, and people with weight and alcohol problems are particularly susceptible to heat reactions, especially during heat waves in areas where moderate climate usually prevails.

Geographic Area
Freeze
The entire county is susceptible to extreme temperatures. Unseasonable cold temperatures can have large impacts on crops in Merced County. The growing season is approximately 257 days per year, and the frost-free period usually extends from mid-February to mid-November. The mean frost-free period in the western part of the county is 225-250 days.

Extreme Heat
The climate in Merced County is hot and arid, and the entire county is susceptible to extreme heat. The agriculturally dominated central region of the county is likely to experience the greatest impacts from large or unseasonable temperature variations. The more urbanized areas of the County may experience the Urban Heat Island Effect due to the amount of impervious surfaces in those areas that absorb and keep heat longer. The HMPC noted the cities of Merced and Dos Palos have experienced annual summer heat waves that have taken place in the past five years and have led to opening of cooling centers.

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Extent (Magnitude/Severity)
Freeze
In 2001, the NWS implemented an updated Wind Chill Temperature index. This index was developed to describe the relative discomfort/danger resulting from the combination of wind and temperature. Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature.

Overall, freeze impacts would likely be limited in the planning area, with the greatest impact being on the agricultural industry.

Figure 4-21 National Weather Service Wind Chill Chart
Source: NWS
Extreme Heat
Figure 4-22 illustrates the relationship of temperature and humidity to heat disorders. The heat index describes how hot the heat‐humidity combination makes the air feel. As relative humidity increases, the air seems warmer than it actually is because the body is less able to cool itself via evaporation of perspiration. As the heat index rises, so do health risks. Specifically:
● When the heat index is 90°F, heat exhaustion is possible with prolonged exposure and/or physical activity.
● When it is 90° to 105°F, heat exhaustion is probable with the possibility of sunstroke or heat cramps with prolonged exposure and/or physical activity.
● When it is 105° to 129°F, sunstroke, heat cramps or heat exhaustion is likely, and heatstroke is possible with prolonged exposure and/or physical activity. ● When it is 130°F and higher, heatstroke and sunstroke are extremely likely with continued exposure.

Physical activity and prolonged exposure to the heat increase the risks.

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Figure 4-22 National Weather Service Heat Index Chart
Source: Source: NWS Note: Since heat index values were devised for shady, light wind conditions, exposure to full sunshine can increase heat index values by up to 15°F. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous.

The NWS has a system in place to initiate alert procedures (advisories, watches, and warnings) when high temperatures are expected to have a significant impact on public safety. The expected severity of the heat determines which type of alert is issued. The “California OES Contingency Plan for Excessive Heat Emergencies” (2014) indicates that through the use of historical weather and mortality data, the NWS and the California Department of Public Health have identified five major types of climate regions within California to account for climate differences among regions in order to recognize what constitutes an excessive heat event in each of the regions. When temperatures spike for two or more consecutive days without an adequate drop in nighttime temperature to cool the outdoor and indoor environments, there is a significant increase in the risk to vulnerable populations.

Overall, extreme heat impacts would likely be limited in the planning area, with the central portions of the County being most affected. Extreme heat will have an impact on vulnerable populations as well as impact the agricultural industry if the event occurs during certain times of the year.

Past Occurrences
A search of records from 1950 to 2020 in the NCEI Storm Events Database showed that between 2000 and 2016 there were 31 frost and freeze events and 13 heat events in Merced County. No records for either hazards were found between 1950 and 2000 or after 2016 in the NCEI database. Since 1972 there have been 4 federally declared disaster in the County for freeze events (refer to Table 4-3). In 2007, 2009 and 2011 and 2012 the USDA designated Merced County as a disaster area due to freeze and extreme cold.

During these events, California's San Joaquin Valley farming communities were hit with freezing temperatures that severely affected the region's crops and resulted in presidential disaster declarations (2007). The declarations made federal funds available to supplement unemployment compensation for farm laborers and other farm industry workers put out of work as a direct result of lost seasonal crops.

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Probability of Future Occurrences
Highly Likely - Temperatures at or above 95°F are common most summer days throughout Merced County, and it is highly likely that extreme heat will continue to occur on an annual basis in the future.

In the past, severe freezes have occurred every few years. Based on the NCEI data, 31 frost and freeze events incidents over a 16-year period equates to a major event every 2 years and a 52 percent chance of a major freeze event in any given year.

Climate Change Considerations
Although heat waves will likely become more frequent, there is also the potential for continued cold outbreaks in winter, even in an overall warmer climate. This could have direct impacts on human health in terms of heat related illness. With the general trend of increased warming of average temperatures, extreme high temperatures will likely increase as well. Cascading impacts include increased stress on water quantity and quality, degraded air quality, and increased potential for more severe or catastrophic natural events such as heavy rain, droughts, and wildfire. Another cascading impact includes increased duration and intensity of wildfires with warmer temperatures. According to the 2013 document, “Preparing California for the Extreme Heat”, Cal-Adapt projects that throughout California urban and rural population centers will experience an average of 40 to 53 extreme heat days by 2050 and an average of 40 days by 2099; compared to a historical average of 4 per year (Cal-Adapt 2013).

Extreme heat has also been shown to accelerate wear and tear on the natural gas system and electrical infrastructure (California Natural Resources Agency 2018a). Projected increases in summer demand associated with rising temperatures may increase risks to energy infrastructure and may exceed the capacity of existing substations and distribution line infrastructure and systems.

Vulnerability Assessment
General Property
The risks of extreme temperatures are often profiled as part of larger hazards, such as severe winter storms or drought. However, as temperature variances may occur outside of larger hazards or outside of the expected seasons but still incur large costs, it is important to examine them as stand-alone hazards.

Extreme cold may also lead to higher electricity and natural gas demands to maintain appropriate indoor heating levels combined with damages caused to the delivery infrastructure such as frozen lines and pipes. Cold temperatures may also impact transportation infrastructure and road conditions through increased wear and stresses on asphalt roads and bridges. Exposed populations may be at risk while waiting for public transportation, particularly when combined with wind chill, and some vehicles may not start, which impacts the commute of the workforce and, in worst case scenarios, the movement of emergency services personnel.

Recent research indicates that the impact of extreme heat, particularly on vulnerable (?) populations, has been historically under-represented. The risks of extreme heat are often profiled as part of larger hazards, such drought or wildfire. However, as temperature variances may occur outside of larger hazards or outside of the expected seasons but still incur large costs, it is important to examine them as stand-alone hazards. Extreme heat may overload demands for electricity to run air conditioners in homes and businesses during prolonged periods of exposure and presents health concerns to individuals that work outside in extreme temperatures. While extreme heat rarely damages buildings, like cold temperatures it can cause infrastructure damage to roads.

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People
Traditionally, the very young and very old are considered at higher risk to the effects of extreme temperatures, but any populations working or recreating outdoors during periods of extreme cold or heat are exposed, including otherwise young and healthy adults and homeless populations. While everyone is vulnerable to extreme temperature incidents, some populations are more vulnerable than others. Extreme heat poses the greatest danger for Merced’s thousands of outdoor laborers who support the County’s agriculture economy who are exposed to extreme temperatures and at higher risk of heat related illnesses than other populations of the county.

The elderly, children, people in poor physical health, and the homeless are also vulnerable to exposure.

Arguably, the young-and-otherwise-healthy demographic may also experience a higher vulnerability of exposure, due to the increased likelihood that they will be out in temperatures of extreme heat and cold, whether due to commuting for work or school, conducting property maintenance such as lawn care, or for recreational reasons.

Critical Facilities
Water infrastructure is at risk from freezing, including line breaks and frozen valve gates affecting the distribution system. The county and municipal governments wrap pipes before freezing temperature events to help prevent damage.

Extreme heat can affect road infrastructure, damaging and buckling road surfaces. Other direct impacts to critical infrastructure includes power line sagging and power surges. Critical infrastructure such as water pumping stations that rely on public utility systems that could be overloaded may result in impacts during extreme heat events. Peak demand exceeding the local utility’s capacity for supply can lead to blackout or brownout conditions, or Public Safety Power Shutoffs (PSPS). The loss of utilities or power outages during extreme heat events could also result in adverse secondary impacts to sensitive populations. Electrical power outages may impact response capabilities or care capabilities for hospitals and clinics.

Economy
Prolonged freezing temperatures can damage or destroy crops, affecting the economy and agricultural jobs in Merced County. According to the USDA RMA Indemnity Report, since 2007 there have been 22,308 acres lost to freeze/frost resulting in $12,933,721 indemnity payments due to insured crop loss.

Annualized crop loss is estimated to be $170,181 due to freeze events.

Extreme heat impacts on the economy may be more indirect compared to other hazards. Merced County has a large agriculture economy. As noted previously outdoor laborers who are exposed to extreme heat and at a high risk of heat related illnesses, and a long-term heat event could cause work interruptions.

Crops are also impacted by heat events and could have an impact on the overall economy in the county.

According to the USDA RMA Indemnity Report, since 2007 there have been 20,207 acres lost to heat resulting in $17,612,071 indemnity payment due to insured crop loss. There is an estimated $187,362 of annualized crop loss due to heat.

Historic, Cultural and Natural Resources
Extreme heat may cause temporary drought-like conditions. For example, several weeks of extreme heat increases evapotranspiration and reduces moisture content in vegetation, leading to higher wildfire vulnerability for that time period even if the rest of the season is relatively moist. Extreme cold can cause vegetation to freeze and cause high stress leading to decline and even disappearance of vegetation on or within landscapes.

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Future Development
Since structures are not usually directly impacted by severe temperature fluctuations, continued development is less impacted by this hazard than others in the plan. However, pre-emptive measures such as construction of green buildings that require less energy to heat and cool, use of good insulation on pipes and electric wirings, and smart construction of walkways, parking structures, and pedestrian zones that minimize exposure to severe temperatures may help increase the overall durability of the buildings and the community to temperature variations. Continued development also implies continued population growth, which raises the number of individuals potentially exposed to variations in temperature. Public education efforts should continue to help the population understand the risks and vulnerabilities of outdoor activities, property maintenance, and regular exposures during periods of extreme heat.

Risk Summary
● Average annual maximum temperature is 76°F and the average annual minimum temperatures is 47°F /48°F.
● On average there is between 97 and 98 days per year above 90°F and about 30 days per year where the minimum temperatures is below freezing (32°F).
● Highest recorded temperatures for the northwestern portion of County is 114°F on July 24, 1902.

While the lowest recorded temperature was 13°F on January 13, 2007. ● High recorded temperatures for the southwestern portion of County is 116°F on July 25, 1931. The lowest recorded temperatures is 14°F on January 11, 1949. ● Extreme temperatures can have considerable impacts on human health, the natural environment and the economy.
● The County’s agriculture economy is at risk of extreme temperatures from outdoor laborers being vulnerable to heat illnesses as well as crop losses due to heat and freeze and frost. ● Since 2007 there has been 42,515 acres of crop lost to extreme temperatures and a combined $30,545,793 indemnity payments made for insured crop loss to due freeze/frost and heat events. ● The very young, the very old, people with poor physical health and the homeless are more susceptible to the impacts of extreme temperatures.
● Climate change is projected to increase temperatures in the Central Valley region of the State. ● Related hazards: Drought, Land Subsidence, Wildfire, Agriculture/Pest Infestation/Plant Disease Table 4-54 Hazard Risk Summary – Extreme Temperatures (Freeze) Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Extensive Highly Likely Critical High
City of Atwater Limited Likely Limited Low
City of Dos Palos Significant Likely Limited Medium
City of Gustine Limited Occasional Negligible Medium
City of Livingston Limited Occasional Negligible Medium City of Los Banos Limited Occasional Negligible Medium
City of Merced Significant Likely Limited Low

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Table 4-55 Hazard Risk Summary – Extreme Temperatures (Extreme Heat) Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Extensive Highly Likely Critical High
City of Atwater Extensive Likely Limited High
City of Dos Palos Extensive Likely Negligible Low
City of Gustine Extensive Likely Limited High
City of Livingston Extensive Likely Limited High
City of Los Banos Significant Highly Likely Negligible Medium City of Merced Extensive Highly Likely Limited Medium

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4.2.8 Severe Weather: Dense Fog
Hazard/Problem Description
Fog results from air being cooled to the point where it can no longer hold all of the water vapor it contains. For example, rain can cool and moisten the air near the surface until fog forms. A cloud-free, humid air mass at night can lead to fog formation, where land and water surfaces that have warmed up during the summer are still evaporating water into the atmosphere. This is called radiation fog. A warm moist air mass blowing over a cold surface also can cause fog to form, which is called advection fog.

The interior California valleys have a unique fog problem called the tule fogs. The tule fog is a radiation fog, which condenses when there is a high relative humidity, typically after a heavy rain, calm winds, and rapid cooling during the night. The longer nights during the winter months create this rapid ground cooling and results in a pronounced temperature inversion at a low altitude, creating a thick ground fog.

Above the cold, foggy layer, the air is typically warm and dry. Once the fog has formed, turbulent air is necessary to break through the inversion. Daytime heating can also work to evaporate the fog in some areas. The tule fogs get their name from the tule reeds, which grew around the swamps and deltas of the great Tulare Lake that once covered the southern end of the San Joaquin Valley.

The tule fog season in Merced County is typically in the late fall and winter (November through March) but can occur as late as May. Fog typically forms rapidly in the early morning hours. Tule fogs can last for days, sometimes weeks. Fog can have devastating effects on transportation corridors in the County.

Nighttime driving in the fog is dangerous and multi-car pileups have resulted from drivers using excessive speed for the conditions and visibility. Tule fog has also been found to be connected to air pollution and exacerbates the naturally occurring fog. A study published in the Journal of Geophysical Research in 2019 found that air pollution is a key contributor to the seasonal fog, and due to the passage of the Clean Air Act in 1970, it has declined about 75 percent since 1980 (Gray 2019).

Figure 4-23 Tule Fog over Central Valley
Source: NASA, Jeff Schmaltz, January 5, 2005

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Geographic Area
The San Joaquin Valley is hemmed in on three sides by mountain ranges, with resulting inversion layers trapping cooler air on the valley floor. This predisposes the area to severe episodes of fog in winter months, when barometric pressures are high, humidity is increased, and ambient temperatures are low. All areas of the county are vulnerable to dense fog events.

Extent (Magnitude/Severity)
Tule fog forms on clear nights when the ground is moist, and the wind is near calm and can be widespread throughout the San Joaquin Valley. On nights like this, the ground cools rapidly. In turn, the moist air above it cools and causes water vapor to condense. Once it has formed, the air must be heated enough to either evaporate the fog or lift it above the surface so that visibilities improve. Common areas for tule fog to form include foothills and valleys. Visibility in tule fog is usually less than an eighth of a mile (about 600 ft or 200 m) but can be much lower. Visibility can vary rapidly; in only a few feet, visibility can go from 10 feet (3.0 m) to near zero.

Fog contributes to transportation accidents and is a significant life safety hazard. These accidents can cause multiple injuries and deaths and could have serious implications for human health and the environment if a hazardous or nuclear waste shipment were involved. Other disruptions from fog include delayed emergency response vehicles and school closures.

In 2018 the NWS in Hanford, California developed the Experimental Fog Severity Index in conjunction with the NWS issues fog advisories to help give motorists advance warning of fog events. A dense fog advisory is issued when widespread dense fog develops, and visibilities drop to one-quarter of a mile or less. The Fog Severity Index has five levels with level 5 being the most severe. Figure 4-24 describes each level of the Index.

Figure 4-24 National Weather Service Experimental Fog Severity Index Source: NWS

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Past Occurrences
The NCEI records 102 dense fog events in the Central San Joaquin Valley that impacted Merced County between 2000 and 2020 (refer to Table 4-52 above). The following are descriptions of three events of record in the NCEI Storm Events Database:
● November 14 - 20 2002 - Following the very substantial rain for the 3-day period from the 7th through the 9th of the month, high pressure aloft built and resided over Interior Central California.

This weather regime, quite conducive to dense morning fog formation, established itself between the 10th and 13th, and maintained itself through the end of the month. The fog was especially widespread from the 14th through the morning of the 21st. Numerous vehicle accidents occurred due to the extremely poor visibilities on Central and Southern San Joaquin Valley roadways. On the 20th along a 3-mile stretch of Highway 99 just north of the Merced-Madera County Line, 50 trucks and cars were involved in multi-vehicle pileups.
● December 1-5, 2002 - With the large rainfall amounts on the San Joaquin Valley floor by November 9th, haze and fog prevailed subsequently for a 30+-day period while the adjacent foothills, mountains, and Kern Desert dried again in rainless conditions. Widespread dense fog from mid to late-November ceased by the morning of the 1st of December on the Valley floor. But patchy dense fog and haze prevailed from the 1st of the month through the 9th before the major precipitation in December began on the 13th. The morning of the 5th had some very dense, but again patchy fog. A 9-vehicle pile-up occurred near Los Banos in Merced County (CAZ89) on Highway 152 around 8:35 AM PST that killed one and injured three others.
● January 10, 2019 - Visibility below a quarter mile was reported in Fresno, Madera, Merced and Atwater. Several school districts either had delayed openings or delayed morning bus service. A head on crash in dense fog near Atwater at 6:12 PST caused one fatality and three injuries.

Probability of Future Occurrences
Likely --Based on the NCEI data, 102 dense fog incidents over a 20-year period equates to a major fog event every 5.1 years and a 20 percent chance of a major fog event in any given year. It is likely that minor fog events will continue to occur annually in the Merced County planning area.

Climate Change Considerations
California’s winter tule fog has declined dramatically over the past three decades, raising a red flag for the state’s multibillion-dollar agricultural industry, according to researchers at UC Berkeley. Crops such as almonds, pistachios, cherries, apricots and peaches go through a necessary winter dormant period brought on and maintained by colder temperatures. Tule fog that descends upon the state’s Central Valley between late fall and early spring, helps contribute to this winter chill. “The trees need this dormant time to rest so that they can later develop buds, flowers and fruit during the growing season,” said biometeorologist and study lead author Dennis Baldocchi. “An insufficient rest period impairs the ability of farmers to achieve high quality fruit yields.” The findings have implications for the entire country since many of these California crops account for 95 percent of U.S. production, the authors noted. The researchers paired NASA and National Oceanic and Atmospheric Administration satellite records with data from a network of University of California weather stations, covering 32 consecutive winters. There was a great deal of variability from year to year, but on average, the researchers found a 46 percent drop in the number of fog days between the first of November and the end of February. Climate forecasts suggest that the accumulation of winter chill will continue to decrease in the Central Valley. Tule fog was also less prevalent in recent years in part due to the multi-year drought.

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Vulnerability Assessment
General Property
Based on historic information, the primary effect of fog has not resulted in significant damages to property, or the losses are typically covered by insurance.

People
Reduced visibility is the greatest risk to people when heavy fog is prevalent. Particularly when fog is dense, it can be hazardous to drivers, mariners and aviators and contributes to numerous accidents each year. To reduce injury and harm, people should avoid driving when dense fog is prevalent, if possible. If driving is pertinent, emergency services advise driving with lights on low beam, watching for California Highway Patrol (CHP) pace vehicles to guide through fog, avoiding stopping on highways, and avoiding crossing traffic lanes.

Critical Facilities
Fog can have devastating effects on transportation corridors in the County. Multi-car pileups have resulted from drivers using excessive speed for the conditions and visibility.

These accidents can cause multiple injuries and deaths and could have serious implications for human health and the environment if a hazardous or nuclear waste shipment were involved. Other disruptions from fog include delayed emergency response vehicles and school closures.

Economy
Economic impacts due to dense fog are generally related to road closures leading to a decrease in travel to businesses. Other economic impacts relate to property damages to vehicles from accidents. As shown in Table 4-52 above there is a recorded $1,060,000 of property damages as a result of dense fog all of which are from traffic accidents in the Central Valley region and the records mention Merced County.

Based on that amount the Merced County region has an estimated average loss expectancy of $10,495 and annualized loss of $1,070,495 due to dense fog events.

Historic, Cultural and Natural Resources
As referred to in the Climate Change Considerations section, California’s winter tule fog has declined dramatically over the past three decades, raising a red flag for the state’s multibillion-dollar agricultural industry. Crops such as almonds, pistachios, cherries, apricots and peaches go through a necessary winter dormant period brought on and maintained by colder temperatures and tule fog that descends upon the state’s Central Valley between late fall and early spring, helps contribute to this winter chill.

Future Development
Population and commercial growth in the County and outside the County will increase the potential for complications with traffic accidents and commerce interruptions associated with dense fog.

Risk Summary
● Tule Fog season begins in late fall and lasts from winter (November – March). ● Between 2000 and 2020 there were 102 dense fog events that impacted Merced County and have resulted in $1,060,000 in property damages, largely due to traffic accidents. ● Fog can have devastating effects on transportation corridors. On November 4, 2002, a 50-vehicle collision occurred on Highway 99 near Merced.
● Major fog events in the County are estimated to occur every 5.1 years or a 20% chance in any given year.
● Related Hazards: Hazardous Materials Incidents

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Table 4-56 Hazard Risk Summary – Dense Fog
Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Extensive Highly Likely Critical High
City of Atwater Extensive Highly Likely Critical High
City of Dos Palos Extensive Highly Likely Critical High City of Gustine Extensive Highly Likely Critical High
City of Livingston Extensive Highly Likely Limited Medium City of Los Banos Extensive Highly Likely Limited Medium City of Merced Extensive Highly Likely Limited Medium

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4.2.9 Severe Weather: Heavy Rain
Hazard/ Problem Description
Most of the adverse weather experienced in Merced takes place in the winter months as heavy rain and thunderstorm events sometimes accompanied by high winds, dense fog events. Dense fog is profiled under 4.2.8 and high winds and tornado events are profiled in 4.3.10.

Merced’s weather is influenced by the Pacific Ocean and routine climate patterns such as El Niño. El Niño is the warm phase of the El Niño-Southern Oscillation, a pattern found in the tropical Pacific when there are fluctuations in temperatures between the ocean and atmosphere. During El Niño, the surface winds across the entire tropical Pacific are weaker than normal and the ocean surface is at above-average temperatures in the central and eastern tropical Pacific Ocean (L’Heureux 2014). El Niño typically develops over North America during the winter season causing the severe winter storms the County often experiences. This climate pattern occurs every few years and brings with it above-average rain and snow across the southern region of United States, especially in California.

Atmospheric rivers, another climate pattern that leads to adverse weather in the County, are responsible for up to 50 percent of California’s precipitation annually and 65 percent seasonally (Arcuni 2019). An atmospheric river (AR) is a long, narrow region of the atmosphere, like a river in the sky, that transports most of the water vapor outside of the tropics. ARs can be 300 miles wide, a mile deep and more than 1,000 miles long and carry an amount of water vapor roughly the same as the average flow of water at the mouth of Mississippi River (NOAA, 2015). Warm water storms over the Pacific Ocean lead to evaporation and create a high concentration of moisture in the air. While prevailing winds create the distinctive river shape, which is often compared “to a fire hose pointed at California” (Arcuni 2019). When an atmospheric river reaches land, it releases the water vapor in the form of rain or snow. Atmospheric rivers play an important role in the global water cycle and are closely tied to both water supply and flooding risk.

Research suggests that atmospheric rivers contributed to the collapse of both Oroville Dam spillways in February 2017 (NASA Global Hydrology Resource Center), as well as the winter flooding in 1861-1862, which completely inundated Sacramento and is considered the worst flood event in California’s history (Ingram 2013). When an atmospheric river forms in the tropical regions of the Pacific near Hawaii it is known as a “Pineapple Express”. This type of atmospheric river can produce as much as five inches in one day (NOAA, 2018). In 2018 two Pineapple Express ARs hit California causing significant heavy precipitation events throughout state.

Geographic Area
Thunderstorms are generally expansive in size. The entire county is susceptible to any of the effects of a severe thunderstorm, including heavy rain.

Extent (Magnitude/Severity)
The heavy precipitation events that Merced County and all of California experiences is often the result of an atmospheric river. Atmospheric rivers are categorized by a unit of measurement known as the Integrated Water Vapor Transport (IVT), which takes into account the amount of water vapor in the system and the wind that moves it around. For a storm to be classified as an atmospheric river it has to reach an IVT threshold of 250 units; 1,000 IVT or more is considered to be “extreme” (Arcuni 2019). In 2019 a system for categorizing the strength and impacts of atmospheric rivers was developed by the Center for Western Weather and Water Extremes (CW3E), out of the Scripps Institution of Oceanography at UC San Diego. The newly developed scale ranks ARs into five categorizes from weak to exceptional.

Unlike the Fujita Scale for tornadoes that focuses on potential damages, the AR scale accounts for both storms that may be hazardous and storms that can provide benefits to the local water supply. A category

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one AR is considered to be primarily beneficial, generally lasting only 24 hours and produces modest rainfall. While a category five AR is considered “exceptional” and primarily hazardous, lasting for several days and associated with heavy rainfall and runoff that may cause significant damages. Table 4-56 below describes the scale further. The CW3E developed the scale as a tool for officials with an operational need to assess flooding potential in their jurisdictions before the storms makes landfall.

Table 4-57 Atmospheric River Categories
Category Potential Impacts
AR Cat 1: Weak Primarily beneficial. For example, a Feb. 2, 2017 AR hit California, lasted 24 hours at the coast, and produced modest rainfall.

AR Cat 2: Moderate Mostly beneficial, but also somewhat hazardous. An atmospheric river on Nov. 19-20, 2016 hit Northern California, lasted 42 hours at the coast, and produced several inches of rain that helped replenish low reservoirs after a drought.

AR Cat 3: Strong Balance of beneficial and hazardous. An atmospheric river on Oct. 14-15, 2016 lasted 36 hours at the coast, produced 5-10 inches of rain that helped refill reservoirs after a drought, but also caused some rivers to rise to just below flood stage.

AR Cat 4: Extreme Mostly hazardous, but also beneficial. For example, an atmospheric river on Jan. 8-9, 2017 that persisted for 36 hours produced up to 14 inches of rain in the Sierra Nevada and caused at least a dozen rivers to reach flood stage.

AR Cat 5: Exceptional Primarily hazardous. For example, a Dec. 29, 1996 to Jan. 2, 1997 atmospheric river lasted over 100 hours at the Central California coast. The associated heavy precipitation and runoff caused more than $1 billion in damages.

Source: Center for Western Weather and Water Extremes, Scripps Institution of Oceanography at UC San Diego. Scale was developed by F. Martin Ralph Director of CW3E in collaboration with Jonathan Rutz of NWS In both February 2018 and 2019 the West Coast experienced six atmospheric rivers. But as the following figure from the Center for Western Weather and Water Extremes shows, California experienced vastly different precipitation totals due to the location of where the atmospheric river made landfall as well as each atmospheric river’s IVT. Using the AR scale developed by CW3E, the ARs in February 2019 were all considered to be moderate to extreme and concentrated more on California, resulting in heavy precipitation.

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Figure 4-25 Atmospheric River Strength and Land Distribution, February 2018 vs. February 2019 Source: Center for Western Weather and Water Extremes, Scripps Institution of Oceanography at UC San Diego

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Past Occurrences
Heavy rains and adverse storms occur in the Merced County primarily during the late fall and winter but have a chance of occurring in every month of the year. According to information obtained from the Western Regional Climate Center (WRCC) the majority of precipitation is produced by storms during January and other winter months. Precipitation during the summer months is in the form of rain showers and is rare.

The NCEI records show heavy rainstorms can cause both widespread flooding which can lead to extensive localized drainage issues. In addition to the flooding that often occurs during these storms, strong winds, when combined with saturated ground conditions, can down very mature trees. Refer to the Flood section for more information related to flooding events in the county. There have been two USDA disaster designations (2016, 2019) for excessive rainfall in Merced County (refer to Table 4-4).

Information from the three representative weather stations introduced in subsection 4.3.6 Severe Weather: General are summarized below and in Figure 4-26 and Figure 4-27.

Northeastern Merced County - Merced Municipal Airport Weather Station (1899-2016) Information from the closest weather station with the most comprehensive data to represent the northeastern county area, the Merced Municipal Airport Weather Station, is summarized below in Figure 4-26 and Figure 4-27. Average annual precipitation recorded at this weather station is 12.27 inches per year. The highest recorded annual precipitation was 21.66 inches in 1998; the highest recorded precipitation for a 24-hour period is 2.20 inches on January 30, 1911. The lowest recorded annual precipitation was 5.50 inches in 1947.

Figure 4-26 Merced Municipal Airport Weather Station Monthly Average Total Precipitation (Period of Record 1899-2016)
Source: WRCC, www.wrcc.dri.edu/

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Figure 4-27 Merced Municipal Airport Weather Station Daily Precipitation Average and Extreme (Period of Record 1899-2016)
Source: WRCC, www.wrcc.dri.edu/
Southwestern Merced County - Los Banos City Weather Station (1906-2016) Information from the closest weather station with the most comprehensive data to represent the southwestern county area the Los Banos Weather Station, is summarized below in Figure 4-28 and Figure 4-29. Average annual precipitation recorded at this weather station is 9.19 inches per year. The highest recorded annual precipitation was 21.08 inches in 1998; the highest recorded precipitation for a 24-hour period is 2.40 inches on January 18, 1914. The lowest recorded annual precipitation was 4.61 inches in 1947.

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Figure 4-28 Los Banos Weather Station Monthly Average Total Precipitation (Period of Record 1906-2016)
Source: WRCC, www.wrcc.dri.edu/
Figure 4-29 Los Banos Weather Station Daily Precipitation Average and Extreme (Period of Record 1906-2016)
Source: WRCC, www.wrcc.dri.edu/

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The NCEI Storm Events Database records 23 heavy rain events in Merced County between 1998 and 2018.

Note no heavy rain events are recorded in the database after 2018. No casualties are recorded for any of the events. As noted above there is a connection between heavy rain events and flooding and is it assumed that the property damages listed in the NCEI database are the results of flooding caused by heavy rain events.

The following table show the records collected from the NCEI Strom Events Database for heavy rain.

Table 4-58 Heavy Rain Events in Merced County, 1998-2018 Location Date Property Damages ($) Crop Damages ($)
Merced 2/1/1998 $2,000,000 $1,400,000
Merced 5/1/1998 $0 $10,200,000
Merced 5/15/2000 $0 $100,000
Merced ARPT 12/13/2002 $0 $0
Merced 4/21/2003 $7,500 $0
Countywide 5/1/2003 $0 $2,000,000
Countywide 12/7/2004 $0 $0
Countywide 12/27/2004 $0 $0
Countywide 1/1/2005 $0 $0
Countywide 1/7/2005 $0 $0
Countywide 1/24/2005 $0 $0
Merced 2/15/2005 $0 $0
Merced ARPT 3/22/2005 $0 $0
Dos Palos/Atwater 9/20/2005 $0 $0
Countywide 1/1/2006 $0 $0
Countywide 3/2/2006 $0 $0
Livingston 3/28/2006 $0 $0
Countywide 4/2/2006 $0 $1,960,000
Merced 2/23/2010 $0 $0
Gustine 12/11/2014 $0 $0
Atwater Muni ARPT 4/27/2016 $0 $0
Santa Nella, Los Banos,
Brito 5/5/2016 $0 $0
Cregan 4/16/2018 $0 $0
Total $2,007,500 $15,660,000
Source: NCEI
Probability of Future Occurrences
Highly Likely – Based on the NCEI data, 23 heavy rain incidents over a 20-year period equates to a major event every 1.2 years and an 87 percent chance of a major heavy rain event in any given year.

Climate Change Considerations
As average temperatures increase over time, this generally will result in higher extreme temperatures and more warming in the atmosphere can trigger climate changes, which could result in more frequent extreme weather events. Pacific Northwest National Laboratory researchers have also found that atmospheric rivers will reach the West Coast more frequently (Gao 2015). Currently, the west receives rain or snow from these atmospheric rivers between 25 and 40 days each year. By the end of this century, days on which the atmospheric rivers reach the coast could increase by a third, or between 35 and 55 days a year.

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Vulnerability Assessment
General Property
The Merced County planning area experiences a rainy season in the winter months through early spring.

These winter storms can include significant precipitation. The primary effect of these storms has not resulted in significant injury or damages to people and property, or the losses are typically covered by insurance. It is the secondary hazards caused by weather, such as floods, that have had the greatest impact on the County. Damage and disaster declarations related to adverse weather have occurred and will continue to occur in the future. Heavy rain and thunderstorms are the most frequent type of severe weather occurrences in the County. Utility outages, downing of trees, debris blocking streets and damage to property can be a direct result of these storm events. Given the nature of these types of storms, the entire County is potentially at risk.

People
Exposure is the greatest danger to people from heavy rain events. People can be caught in rising waters and need to be rescued.

Critical Facilities
Because of the unpredictability of heavy rain events, most critical facilities and infrastructure that is above ground is equally exposed to the storm’s impacts. Due to the random nature of this hazards, a more specific risk assessment was not conducted for this plan.

Economy
Economic impact of a heavy rain event is typically short-term. Generally, long-term economic impacts center more around hazards that cascade from a heavy rain even such as flooding.

In general, all severe weather poses a risk to agriculture economy in the county. Table 4-58 below describes the crops losses related to heavy rain events and associated indemnity amounts or loss payments from the USDA, RMA in the past 13 years. Merced County experiences an estimated $249,076 annualized loss due to crop damages from heavy rain events.

Table 4-59 Crops Loss Due to Heavy Rain, Risk Management Agency Crop Indemnity Reports, 2007-2020
Year Net
Determined
Acres
Indemnity
Amount
2007 354.18 $189,228
2009 1,639.58 $1,464,029
2010 4,173.48 $2,055,617
2011 584 $280,280
2012 1,475.48 $359,758
2013 354.6 $106,905
2014 3,545 $1,916,895
2015 3,303.7 $2,974,961
2016 1,742.3 $2,473,741
2017 4,920.1 $3,936,051
2018 766.47 $682,953
2019 6,741.8 $4,983,748
2020 781.8 $743,567
Total 30,382.49 $22,167,733
Source: USDA RMA

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Historic, Cultural and Natural Resources
As a natural process, the impacts of most heavy rain events by themselves are part of the overall natural cycle and do not cause long-term consequential damage.

Future Development
New critical facilities, such as communication towers should be built to withstand heavy rain damage.

Future development projects should consider adverse weather hazards at the planning, engineering and architectural design stage with the goal of reducing vulnerability. Stormwater master planning and site review should account for buildings to withstand heavy rain events considered for all new development.

Thus, development trends in the County are not expected to increase overall vulnerability to the hazard but all development will be affected by adverse weather and storm events and population growth will increase potential exposure.

Risk Summary
● During the 20-year period of 1998-2018 there were 23 heavy rain events in Merced County. ● Average annual precipitation ranges from 9.19 inches the southern portion of the County to 12.27 inches the northern portion.
● The County experiences an estimated $249,076 annualized crop loss due to heavy rain events. ● Related Hazards: Flooding, Landslide
Table 4-60 Hazard Risk Summary – Heavy Rain
Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Extensive Highly Likely Critical High
City of Atwater Extensive Highly Likely Critical High
City of Dos Palos Extensive Highly Likely Critical High City of Gustine Extensive Highly Likely Critical High
City of Livingston Extensive Highly Likely Critical High City of Los Banos Extensive Highly Likely Limited Medium City of Merced Extensive Highly Likely Limited Medium

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4.2.10Severe Weather: High Wind/Tornado
Hazard/ Problem Description
High winds, often accompanying severe thunderstorms, can cause significant property and crop damage, threaten public safety, and have adverse economic impacts from business closures and power loss.

Windstorms in Merced County are typically straight-line winds. Straight-line winds are generally any thunderstorm wind that is not associated with rotation (i.e., is not a tornado). It is these winds, which can exceed 100 mph that represent the most common type of severe weather and are responsible for most wind damage related to thunderstorms. These winds can overturn mobile homes, tear roofs off houses, topple trees, snap power lines, shatter windows, and sandblast paint from cars. Other associated hazards include utility outages, arcing power lines, debris blocking streets, dust storms, and an occasional structure fire.

Tornadoes are another severe weather hazard that can affect the Merced County planning area.

Tornadoes form when cool, dry air sits on top of warm, moist air. Tornadoes are rotating columns of air marked by a funnel-shaped downward extension of a cumulonimbus cloud whirling at destructive speeds of up to 300 mph, usually accompanying a thunderstorm. Tornadoes are the most powerful storms that exist. They can have the same pressure differential that fuels 300-mile-wide hurricanes across a path only 300-yards wide or less.

Geographic Area
Wind and tornadoes have the potential to happen anywhere in the County. The resulting damage from wind and tornado events may be most severe in the downtown areas of incorporate communities where there are more large trees, infrastructure, and higher density development.

The National Renewable Energy Laboratory (NREL) collects data on wind resources in the United States to help determine the location of new wind energy sites. Figure 4-30 from the NREL Wind Prospector webviewer shows the average annual wind speed in Merced County at the height of 100 meters. The eastern and central portions of the County have average wind speeds between 4.50 meters/second and

5.50 meters/second. The wind speeds in the western portion of the County vary greater than the eastern portions. Average wind speeds in western Merced County range from less than 4.00 meters/second to

7.00 meter/second in northwest.

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Figure 4-30 Merced County Average Annual Wind Speed at 100 meters Source: NREL Wind Prospector
Extent (Magnitude/Severity)
High winds and tornadoes can cause damage to property and loss of life. While most tornado damage is caused by violent winds, most injuries and deaths result from flying debris. Property damage can include damage to buildings, fallen trees and power lines, broken gas lines, broken sewer and water mains, and the outbreak of fires. Agricultural crops and industries may also be damaged or destroyed. Access roads and streets may be blocked by debris, delaying necessary emergency response.

In 2007, the NWS began rating tornadoes using the Enhanced Fujita Scale (EF-scale). The EF-scale is a set of wind estimates (not measurements) based on damage. Its uses three-second gusts estimated at the point of damage based on a judgment of eight levels of damage to the 28 indicators listed in Table 4-60.

These estimates vary with height and exposure. Standard measurements are taken by weather stations in open exposures.

Table 4-60 describes the EF-scale ratings versus the previous Fujita Scale used prior to 2007 (NOAA 2007).

Table 4-61 The Fujita Scale and Enhanced Fujita Scale
Fujita Scale Derived Operational EF-Scale
F Number
Fastest ¼
mile (mph)
3-second
gust (mph) EF Number
3-second
gust (mph) EF Number
3-second gusts
(mph)
0 40-72 45-78 0 65-85 0 65-85
1 73-112 79-117 1 86-109 1 86-110

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Fujita Scale Derived Operational EF-Scale
F Number
Fastest ¼
mile (mph)
3-second
gust (mph) EF Number
3-second
gust (mph) EF Number
3-second gusts
(mph)
2 113-157 118-161 2 110-137 2 111-135
3 158-207 162-209 3 138-167 3 136-165
4 208-260 210-261 4 168-199 4 166-200
5 261-318 262-317 5 200-234 5 Over 200
Source: NWS. Notes: EF - Enhanced Fujita F – Fujita mph - Miles per Hour Figure 4-31 illustrates the potential impact and damage from a tornado.

Figure 4-31 Potential Impact and Damage from a Tornado
Source: NOAA NWS, Storm Prediction Center
The damaging effects of wind speed are measured using the Beaufort Wind Scale as shown in Table 4-61 below. This scale only reflects land-based effects and does not take into consideration the effects of wind over water.

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Table 4-62 Beaufort Wind Scale
Wind Speed
(mph) Description – Visible Condition
0 Calm; smoke rises vertically
1-4 Light air; direction of wind shown by smoke but not by wind vanes 4-7 Light breeze; wind felt on face; leaves rustle; ordinary wind vane moved by wind 8-12 Gentle breeze; leaves and small twigs in constant motion; wind extends light flag 13-18 Moderate breeze; raises dust and loose paper; small branches are moved 19-24 Fresh breeze; small trees in leaf begin to sway; crested wavelets form on inland water 25-31 Strong breeze; large branches in motion; telephone wires whistle; umbrellas used with difficulty 32-38 Moderate gale whole trees in motion; inconvenience in walking against wind 39-46 Fresh gale breaks twigs off trees; generally, impedes progress 47-54 Strong gale slight structural damage occurs; chimney pots and slates removed 55-63 Whole gale trees uprooted; considerable structural damage occurs 64-72 Storm very rarely experienced; accompanied by widespread damage 73+ Hurricane devastation occurs
Source: NWS
Based on NCEI records between 1955 and 2019 there have been a combined 36 strong wind/high wind/thunderstorm winds and 32 tornado/funnel cloud events in Merced County which has resulted in a total of $1,925,800 in property damage. The most damaging event took place on January 20, 2010 and was a 59-mph wind event that resulted in $750,000 in property damages. Overall, high wind event impacts would likely be limited, with a majority of impacts being related to property damages caused my downed trees as well as power outages.

In the past 65 years all the tornado events that have taken place in Merced County have been between F0-F1 or EF0 tornadoes. However, it should be noted that, although unlikely, larger tornadoes could occur.

Should the County be hit by an EF-3 or higher tornado, it can be extrapolated that because of its relative size and the potential size and length of a tornado’s path a significant portion of the County could be impacted, resulting in property and crop damage and loss of life.

Tornado impacts to the County would likely be negligible, with less than 10 percent of the planning area affected by events in the EF0-2 range, though stronger tornadoes are possible. The impact to quality of life or critical facilities and functions in the affected area would depend on where the tornado occurred.

Injuries or deaths are possible due to wind thrown trees or property damage caused by wind events.

Overall, impacts from high wind and tornado events would likely be negligible, with less than 10 percent of property severely damaged and shutdown of facilities due to loss of power for 24 hours or less.

Past Occurrences
During the rainy season, the Merced planning area is prone to relatively strong thunderstorms, sometimes accompanied by high winds and tornadoes. While tornadoes do occur occasionally, most often they are of F0/EF0 intensity. The NCEI Storm Events Database does not record any F2, or F3 or anything events greater than EF0 events that have occurred in the planning area in the past. Table 4-62 Past High Wind and Tornado Events contains incident descriptions for significant historic events. In addition to the events listed in the NCEI database, there was a USDA disaster designation declared for Merced County in 2016 for “severe weather including excessive rainfall and high winds” (refer to Table 4-4).

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Table 4-63 Past High Wind and Tornado Events in Merced County, 1955-2019 Hazard Type Date Location Magnitude
Property
Damages
($)
Crop
Damages
($)
Deaths Injuries
Tornado 4/18/1955 Merced County Unknown $0 $0 0 0
Thunderstorm
Wind 7/6/1957 Merced County 70mph $0 $0 0 0
Tornado 4/22/1967 Merced County F1 $0 $0 0 0
Tornado 4/5/1975 Merced County F0 $25,000 $0 0 0
Tornado 3/4/1978 Merced County F1 $250,000 $0 0 1
Tornado 2/19/1986 Merced County F0 $25,000 $0 0 0
Tornado 3/26/1991 Merced County F0 $0 $0 0 0
Thunderstorm
Wind 6/15/1995 Merced/Dos Palos Unknown $50,000 $3,000,000 0 0 Thunderstorm
Wind 4/1/1996 Los Banos/Gustine 80mph $320,000 $100,000 0 0 Tornado 4/1/1996 Merced F0 $10,000 $0 0 0
Tornado 11/22/1996 Merced F1 $45,000 $0 0 0
Tornado 11/13/1997 Los Banos F0 $5,000 $0 0 0
Tornado 2/14/1998 Los Banos F0 $0 $0 0 0
Funnel Cloud 3/25/1998 Atwater/Livingston/
Merced Unknown $0 $0 0 0
Funnel Cloud 3/28/1998 Plainsburg Unknown $0 $0 0 0
Funnel Cloud 4/5/1998 Dos Palos/Los
Banos Unknown $0 $0 0 0
Funnel Cloud 1/31/1999 Merced Unknown $0 $0 0 0
High Wind 1/10/2001 Countywide Unknown $20,000 $0 0 4
High Wind 5/2/2001 Countywide 57mph $75,000 $1,960,000 0 0 High Wind 8/29/2001 Santa Nella Unknown $0 $0 0 0
High Wind 11/24/2001 Countywide Unknown $0 $0 0 0
High Wind 12/2/2001 Countywide Unknown $0 $0 0 0
High Wind 3/13/2002 Countywide Unknown $0 $0 0 0
High Wind 6/8/2002 Countywide Unknown $0 $0 0 0
High Wind 6/9/2002 Countrywide Unknown $0 $0 0 0
High Wind 8/3/2002 Los Banos Muni
ARPT Unknown $0 $0 0 0
Strong Wind 12/14/2002 Countywide 49mph $0 $0 0 0
Strong Wind 12/16/2002 Countywide 36mph $5,000 $0 0 0
Tornado 12/16/2002 Merced ARPT F1 $400,00 $0 0 0
Strong Wind 12/19/2002 Countywide 46mph $5,000 $0 0 0
Strong Wind 12/28/2002 Countywide 34mph $4,000 $0 0 0
Funnel Cloud 5/3/2003 Atwater/Merced/
Livingston Unknown $0 $0 0 0
Strong Wind 2/25/2004 Countywide Unknown $0 $0 0 0
Funnel Cloud 10/17/2004 Countywide 40mph $0 $0 0 0
Strong Wind 10/19/2004 Countywide 41 $1,000 $0 0 0
Strong Wind 1/7/2005 Countywide 36 mph $10,000 $0 0 0
High Wind 1/7/2005 Countywide 57.4 mph $150,000 $150,000 0 0 Funnel Cloud 3/20/2005 Los Banos Unknown $0 $0 0 0
Strong Wind 3/22/2005 Countywide 40 mph $5,000 $0 0 0

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Hazard Type Date Location Magnitude
Property
Damages
($)
Crop
Damages
($)
Deaths Injuries
Tornado 4/8/2005 Ballico F0 $25,000 $50,000 0 0
Funnel Cloud 4/8/2005 Gustine Unknown $0 $0 0 0
Funnel Cloud 1/18/2006 Gustine/El Nido Unknown $0 $0 0 0 Funnel Cloud 3/28/2006 Merced Unknown $0 $0 0 0
Tornado 3/28/2006 Atwater/Merced/
Merced ARPT F0 $25,000 $0 0 0
Funnel Cloud 4/14/2006 Atwater Unknown $0 $0 0 0
Strong Wind 9/8/2006 Countywide 40 mph $1,000 $0 0 0
Thunderstorm
Wind 10/29/2007 Cregan 55 mph $60,000 $0 0 0
Strong Wind 2/23/2008 Countywide 39 mph $0 $12,000 0 0
Strong Wind 5/31/2008 Countywide 30 mph $500 $0 0 0
Strong Wind 6/10/2008 Countywide 39 mph $200 $1,000 0 0 Strong Wind 6/26/2008 Countywide 33 mph $1,000 $0 0 0
Funnel Cloud 1/25/2009 Stevinson Unknown $0 $0 0 0
Tornado 2/9/2009 Merced ARPT EF0 $0 $0 0 0
High Wind 1/20/2010 Countywide 59 mph $750,000 $0 0 0
Strong Wind 3/6/2012 Countywide 36 mph $35,000 $0 0 0
Funnel Cloud 4/12/2012 Atwater Unknown $0 $0 0 0
Funnel Cloud 3/2/2014 Dos Palos Unknown $0 $0 0 0
Strong Wind 12/11/2014 Countywide 48 mph $0 $500,000 0 0 Strong Wind 3/5/2016 Countywide 35mph $100 $0 0 0
Strong Wind 2/1/2017 Countywide 30 mph $1,000 $0 0 0
Funnel Cloud 3/21/2017 Castle AFB Unknown $0 $0 0 0
High Wind 12/16/2017 Countywide 51 mph $0 $0 0 0
Strong Wind 1/6/2019 Countywide 43 mph $16,000 $0 0 0
Strong Wind 1/17/2019 Countywide 30 mph $1,000 $0 0 0
Funnel Cloud 3/27/2019 Livingston Unknown $0 $0 0 0
Strong Wind 4/9/2019 Countywide 39 mph $5,000 $0 0 0
Funnel Cloud 5/21/2019 Los Banos Unknown $0 $0 0 0
Funnel Cloud 11/28/2019 El Nido Unknown $0 $0 0 0
Total $1,925,800 $5,773,000 0 5
Source: NCEI Storm Events Database, Notes: mph – Miles per Hour, ARPT – Airport, AFB – Airforce Base Figure 4-32 and Figure 4-33 show the location of the past wind and tornado events in Merced County based on data from NOAA’s NWS Storm Prediction Center.

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Figure 4-32 Merced County Wind Events (1950 -2019)

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Figure 4-33 Tornado Events in Merced County, 1950 -2019

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Probability of Future Occurrences
Highly Likely – Sixty-eight high wind and tornado events have occurred in Merced County over 64 years of record keeping, which equates to one high wind or tornado event every 1.1 years, on average, and a 94 percent chance of a high wind or tornado event occurring in any given year. Historical wind activity within the planning area indicates that the area will likely continue to experience high wind during thunderstorm events with a potential of the formation of funnel clouds and low intensity tornadoes during adverse weather conditions. The actual risk to the County is dependent on the nature and location of any given thunderstorm or tornado event.

Climate Change Considerations
There presently is not enough data or research to quantify the magnitude of change that climate change may have related to tornado frequency and intensity. NASA’s Earth Observatory has conducted studies that aim to understand the interaction between climate change and tornadoes. Based on these studies meteorologists are unsure why some thunderstorms generate tornadoes and others don’t, beyond knowing that they require a certain type of wind shear. Tornadoes spawn from approximately one percent of thunderstorms, usually supercell thunderstorms that are in a wind shear environment that promotes rotation. Some studies show a potential for a decrease in wind shear in mid-latitude areas. Because of uncertainty with the influence of climate change on tornadoes, future updates to the mitigation plan should include the latest research on how the tornado hazard frequency and severity could change. The level of significance of this hazard should be revisited over time.

As for wind, studies referenced in California’s Fourth Climate Assessment indicated that extreme fire weather, particularly in the form of hot and dry winds, can strongly influence shrub-land fire regimes.

Strong winds have also been now associated with severe forest fires in California meaning climate change impacts on wind patterns may also affect forest health and wildfire susceptibility. Lastly, other ongoing research compiled in the recent climate assessment has resulted in different conclusions on the effect of climate change on wind regimes, particularly extreme wind events, such as the Santa Ana and Diablo winds that created some of the most devastating wildfires (California Natural Resources Agency 2018a). At this time, these changing factors are not well understood and are still being incorporated into state and regional research and risk analysis.

Vulnerability Assessment
General Property
General damages are both direct (what the wind event physically destroys) and indirect, which focuses on additional costs, damages and losses attributed to secondary hazards spawned by the event, or due to the damages caused by the wind event. Depending on the magnitude of the wind events as well as the size of the tornado and its path, a tornado is capable of damaging and eventually destroying almost anything.

Construction practices and building codes can help maximize the resistance of the structures to damage.

Secondary impacts of damage caused by wind events often result from damage to infrastructure. Downed power and communications transmission lines, coupled with disruptions to transportation infrastructure, create difficulties in reporting and responding to emergencies. These indirect impacts of a wind event put tremendous strain on a community. In the immediate aftermath, the focus is on emergency services.

Downed trees caused by a wind event are a common occurrence in the County. Falling trees can cause significant damage to property and put people at risk. Due to multiple years of drought in the County, many trees in the area have been impacted making them more susceptible to blow-down during wind events.

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People
Community members are the most vulnerable to high wind and tornado events. The availability of sheltered locations such as basements, buildings constructed using tornado-resistant materials and methods, and public storm shelters, all reduce the exposure of the population. However, there are also segments of the population that are especially exposed to the indirect impacts of high winds and tornadoes, particularly the loss of electrical power. According to the data obtained from emPower.com, a website maintained by the U.S. Department of Health and Human Services, 4%, or 1,412 of the 36,689 of the Medicare beneficiaries in the County rely on medical equipment that is dependent on electricity in order to live independently. These populations include the elderly or disabled, especially those with medical needs and treatments dependent on electricity. Nursing homes, community-based residential facilities, special needs housing facilities, and isolated communities are also vulnerable because of life support needs if electrical outages are prolonged, since backup power generally operates only minimal functions for a short period of time.

Following the unprecedented 2018 wildfire season in California, PG&E announced it will be conducting PSPS when there are high winds and dry conditions and generally a heightened fire risk forecasted. The outages could last several days, and PG&E has suggested customers be prepared for outages that could last longer than 48 hours. A majority of Merced County could be affected by the power outages.

Critical Facilities
Both winds and tornadoes may impact exposed critical infrastructure such as power lines; depending on the impact and the function, this could cause a short-term economic disruption. The most common problems associated with tornadoes and high winds are loss of utilities. Downed power lines can cause power outages, leaving large parts of the county isolated, and without electricity, water, and communication. Damage may also limit timely emergency response and the number of evacuation routes.

Downed electrical lines following a storm can also increase the potential for lethal electrical shock.

Damaging winds can also cause wildfires; refer to the Wildfire section for more information on the County’s vulnerability to wildfires.

In an effort to mitigate the impacts of PSPS, the State of California has allocated PSPS Resiliency funds for counties, cities, tribes and state agencies to “procure fixed, long-term emergency electrical generation equipment, develop continuity plans, risk assessments for critical infrastructure, post event reports, and public education material or supplies to prepare of electric disruption” (Cal OES 2021). In fiscal year 2019- 20 Merced County was allocated $422,987 from the PSPS Resiliency Allocation to counties, to purchase and install generators at County fire stations, backup generators and lighting infrastructure for the Merced County Operations Areas and purchase a battery-powered backup Public Safety Answering Point for all dispatch centers within the Merced County Operational Area.

Economy
Winds typically don’t have long-term impacts on the economy, although wind does have an impact on the agriculture economy in the county. As shown in Table 4-63, wind events have been a leading cause of crop loss in the past three years (2007 – 2019), resulting in over $2 million in loss payments from the USDA and more than 3,000 acres lost to high wind events. Merced County experiences an estimated $187,255 annualized loss due to crop damages from excessive wind events.

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Table 4-64 Crops Loss Due to High Wind, Risk Management Agency Crop Indemnity Reports, 2007-2019
Year Net
Determined
Acres
Indemnity
Amount
2007 372.4 $97,945
2008 327.02 $130,399
2012 32.4 $2,159
2013 1,624.8 $1,267,860
2014 176 $171,649
2015 301.9 $75,625
2016 7.4 $11,792
2017 398.68 $303,600
2019 298 $186,034
Total 3,539 $2,247,063
Source: USDA RMA
Historic, Cultural and Natural Resources
High winds and tornadoes can cause massive damage to the natural environment, uprooting trees and other debris. This is part of a natural process, however, and the environment will return to its original state in time.

Future Development
As the County continues increase in population, the number of people and housing developments exposed to the hazard increases. Adherence to current building codes, coupled with proper education on building techniques and the use of sturdy building materials, attached foundations, and other structural techniques may minimize the property vulnerabilities. Public shelters at parks and open spaces may help reduce the impacts of tornadoes and high wind events on the recreational populations exposed to storms.

Risk Summary
● Between 1955 and 2019 there were a combined 68 high wind (36) and tornado (32) events in the County.
● Wind and tornado events have resulted in $1,925,800 in property damages. The most damaging event took placed on January 20, 2010 with 59 mph wind causing $750,000 in property damages. ● Excessive wind has caused 3,539 acres to be lost and $2,247,063 crop loss payment made by the USDA to farmers in the County.
● PSPS pose a risk to individuals in the County who depend on electricity to live independently. Four percent of Medicare Beneficiaries in the County are electricity dependent. ● Related Hazards: Extreme heat, Heavy Rain, Agriculture/Pest and Crop Disease, Wildfire

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Table 4-65 Hazard Risk Summary – High Wind/Tornado
Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Extensive Highly Likely Critical High
City of Atwater Extensive Highly Likely Critical High
City of Dos Palos Extensive Highly Likely Critical High City of Gustine Extensive Highly Likely Limited Medium
City of Livingston Extensive Highly Likely Limited Medium City of Los Banos Extensive Highly Likely Limited Medium City of Merced Extensive Highly Likely Limited Medium

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4.2.11Subsidence
Hazard/Problem Description
Land subsidence is defined as the vertical sinking of the land over natural or manmade underground voids. Subsidence is common in several areas of California, usually as a result of groundwater pumping, peat loss, or oil and gas extraction. Fluctuations in the level of underground water caused by pumping or by injecting fluids into the earth can initiate sinking to fill the empty space previously occupied by water or soluble minerals. Weight, including surface developments such as roads, reservoirs, and buildings, and manmade vibrations from such activities as blasting and heavy truck or train traffic can accelerate the natural processes of subsidence, or induce subsidence over manmade voids.

The 2018 California SHMP profiles subsidence as a secondary impact of drought. Through reduced availability of surface water, groundwater pumping in order to meet water needs. According to a study published by Yale Environmental Review, approximately 1 million people in the San Joaquin Valley rely on groundwater pumping for drinking water, and thousands of farmers rely on groundwater to irrigate crops.

While groundwater pumping occurs in both drought and non-drought years to support urban, rural, and agricultural water needs, the 2018 California State HMP notes that it is greatly increased during dry years.

Land subsidence due to groundwater pumping can permanently damage or collapse underground aquifers, increase flood risk in low-lying areas, and pose hazards to buildings, infrastructure, and water storage facilities.

Subsidence can result in serious, localized structural damage to buildings, roads, irrigation ditches, canals, streams, underground utilities, and pipelines. It can disrupt and alter the flow of surface or underground water. The consequences of improper use of land subject to ground subsidence can be excessive economic losses, including the high costs of repair and maintenance for buildings, irrigation works, highways, utilities, and other structures. This results in direct economic losses to citizens as well as indirect economic losses through increased taxes and decreased property values.

Geographic Area
Figure 4-34 below shows areas statewide that have a recent history of subsidence or are known to be at an increased risk of subsidence. Most studies and concern about land subsidence in California have focused on the Santa Clara Valley, San Joaquin Valley, Sacramento Valley, Antelope Valley, Coachella Valley, and Mojave River Basin Areas.

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Figure 4-34 Historic Land Subsidence in California
Source: California DWR, November 2014 Public Update for Drought Response The Merced Subbasin GSA has a focused map of subsidence in the vicinity of Merced County, shown in Figure 4-35 below. This agency was created for the purpose of forming a joint powers agency that will be the GSA for a portion of the Merced Groundwater Subbasin. The Merced Subbasin GSA developed and adopted the Merced Groundwater Sustainability Plan in December 2019. The implementation of plan will address the SGMA requirements and achieve the sustainability goals outlined in SGMA, in addition to positive impacts to future subsidence in the County.

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Figure 4-35 Merced County Area Subsidence
Source: Merced County
Extent (Magnitude/Severity)
A lack of data makes it difficult to predict the magnitude of future land subsidence incidents in Merced County. As shown in Figure 4-35 above, most of the documented land subsidence in the county has been of 0.5 feet or less per year. Much of this subsidence is continuous and occurs gradually over a vast area of the county. However, that can still be enough to cause structural issues. Sudden and localized subsidence events, such as sinkholes, can cause damage to building foundations, roadways, and utilities. Such events have been documented in nearby Fresno and Madera counties, where sinkholes or sudden subsidence has damaged and closed roads. Ongoing displacements of as much as 12” per year have been documented in other parts of the state. As areas of the county continue to gradually sink, the impacts on infrastructure may become more apparent.

Previous Occurrences
While actual effects of subsidence are visible throughout the County, research on the hazard produced thus far has not produced records of any specific events. Some areas of the County have subsided 10-15 feet over the past 50 years according to the HMPT.

Probability of Future Occurrences
Land subsidence has been a recurring issue in Merced County for decades and can be expected to continue in the future. The frequency of future land subsidence incidents in the county will largely be dependent on the mitigation actions and pumping regulations initiated by the state, the county, and local regulations. Based on past trends of gradual subsidence throughout the entire San Joaquin Valley and the

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continued dependence on groundwater pumping, it can be assumed that subsidence will continue in the future, with increased rates of subsidence coinciding with drought years.

Climate Change Considerations
The most likely impact that climate change will have on land subsidence risk is the potential for extended and severe drought, which could likely result in more groundwater pumping and human-induced subsidence. During periods of drought, water levels may be drawn too low, which results in an irreversible compaction of aquifers. The water cannot recharge the layers, causing permanent subsidence and diminishment of groundwater storage capacity.

Vulnerability Assessment
General Property
The lack of detailed data on land subsidence in Merced County makes it difficult to quantify past or potential future losses. Most subsidence instances result in relatively minor damage and settling of buildings. But in some cases, subsidence can result in serious structural damage to buildings, roads, irrigation ditches, underground utilities, and pipelines, potentially resulting in the complete loss of the structure. Subsidence can also disrupt and alter the flow of surface or underground water, as well as reducing the future capacity of aquifers.

People
This hazard typically results in property damage, not risk to human life. In the event of a sudden sinkhole, it would be possible for people to sustain injuries if they were walking or driving and were caught in the sinkhole.

Critical Facilities and Infrastructure
Linear infrastructure (roads, buried pipelines) tends to have the most risk to land subsidence. Statewide, subsidence has caused damage to dams and levees, canals, roads and bridges, water and sewer lines, pipelines, well casings, and aircraft runways, in addition to a variety of buildings and other structures.

Highways 59 and 152 traverse areas of historic subsidence in the County. The threat to the California Aqueduct has been identified as a significant concern for the state. Evidence of the gradual impacts of subsidence on infrastructure in the San Joaquin Valley can be seen in Figure 4-36 below. This image was taken from the California Water Foundations Summary Report on Land Subsidence from Groundwater Use in California. The bridge shown is over the Outside Canal north of Mendota, California. While it is partially submerged in this image, the bridge used to have canal inspections by the Central California Irrigation District staff conducted from a boat passing under the bridge.

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Figure 4-36 Evidence of Gradual Land Subsidence, Partially Submerged Russell Avenue Bridge, Mendota, CA
Economy
Damage resulting from land subsidence can cause direct economic losses in the form of needed structural repairs to affected buildings and facilities. It can also result in indirect losses, such as from increased taxes and decreased property values. Subsidence may impact tourism and shipping industries if transportation routes are affected.

Historic, Cultural, and Natural Resources
Historic and cultural facilities are just as susceptible to subsidence related damage as other structures.

However, there is not sufficient data to identify specific historical or cultural facilities at increased risk from this hazard.

Groundwater pumping can cause significant impacts to underground water resources, and the resulting subsidence events may further disrupt and alter the flow of surface or underground water, in a cyclical pattern of environmental degradation. Furthermore, soil compaction resulting from subsidence can permanently reduce aquifer capacity, impacting water supplies long into the future.

Future Development
The areas of the county which have experience the greatest historic rates of subsidence are largely in the middle of the county, which is occupied by the Merced National Wildlife Refuge, San Luis National Wildlife Refuge, and Great Valley Grasslands State Park. As such, future development of these areas will be significantly restricted, and growth will be limited. While vulnerability to this hazard is not anticipated to increase with new development, increased water pumping resulting from the demand of new development has the potential to increase the frequency and severity of subsidence. This could be

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especially important in Los Banos, given that area has higher subsidence potential. Increased efforts to monitor and manage groundwater pumping, increased accuracy of mapping, and emphasis on appropriate grading and ground compaction during development will help alleviate vulnerability for future development in unknown areas of risk.

Risk Summary
While a significant portion of Merced County is at risk from ongoing land subsidence, the gradual nature of this hazard makes the overall significance of this hazard low. ● The gradual nature of land subsidence incidents limits their overall impact, in terms of property damage, at the county level.
● The entire San Joaquin Valley is vulnerable to land subsidence, and Merced County is vulnerable due to its dependence on agriculture and groundwater pumping. ● There is a shortage of data on specific occurrence of this hazard in Merced County. Most studies on land subsidence in California have focused on the Santa Clara Valley, San Joaquin Valley, Sacramento Valley, Antelope Valley, Coachella Valley, and Mojave River Basin Areas, however there is not extensive information on individual subsidence events.
● Increased drought conditions resulting from climate change has the potential to result in more groundwater pumping, which could lead to more human-induced subsidence; groundwater sustainability planning and management could help offset future subsidence. ● Land subsidence can alter the flow of surface or underground water, an impact that may not be noticed until long after the fact.
● Related Hazards: Drought
Table 4-66 Hazard Risk Summary – Subsidence
Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Extensive Likely Negligible Low
City of Atwater Limited Occasional Negligible Low
City of Dos Palos Limited Occasional Negligible Low
City of Gustine Limited Unlikely Negligible Low
City of Livingston Limited Occasional Negligible Low
City of Los Banos Limited Likely Negligible Low
City of Merced Limited Occasional Negligible Low

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4.2.12Wildfire
Hazard/Problem Description
A wildfire is an uncontrolled fire spreading through vegetative fuels, posing danger and destruction to property and watersheds. While wildfires are often the direct result of lightning strikes, they can be caused by downed powerlines or mechanical equipment or are the result of human activities like landscape debris burns, carelessness, or arson. Wildfires often start in undeveloped areas and public land areas, such as state and federal lands, but can spread to urban areas where structures and other human development are more concentrated. The predominant dangers from wildfires are:
● Injury or loss of life to people in the affected area; and ● The destruction of vegetation, property, wildlife.

Communities throughout California are increasingly concerned about wildfire safety as increased development in the foothills and mountain areas and subsequent fire control practices have affected the natural cycle of the ecosystem. Wildfire risk is predominantly associated with wildland-urban interface areas, a general term that applies to development adjacent to landscapes that support wildfire. However, significant wildfires can also occur in heavily populated areas.

Merced County is exposed to a variety of wildfire hazard conditions that varies based on fuels, topography, weather, and human behavior. CAL FIRE, as required by government code 51181, has undertaken a statewide program to map areas of potential wildfire severity, and to describe the potential for wildfires to occur in a given area; the resulting Fire Hazard Severity Zones are shown in Figure 4-37 below.

It should be noted that fires are also an important natural component of Merced County’s ecosystem.

Wildlands need to burn periodically to naturally maintain viable environments. Fuel maintenance (controlled burns, mowing, cattle grazing, and other means) is a necessary replacement to uncontrolled wildland fires because of threats to human habitation. Development patterns in rural lands can reduce the ability to manage fuel and defend “values at risk”.

Generally, there are three major factors that sustain wildfires and predict a given area’s potential to burn.

These factors are fuel, topography, and weather.
● Fuel—Fuel is the material that feeds a fire and is a key factor in wildfire behavior. Fuel is generally classified by type and by volume. Fuel sources are diverse and include everything from dead tree leaves, twigs, and branches to dead standing trees, live trees, brush, and cured grasses. Also, to be considered as a fuel source are manmade structures, such as homes and other associated combustibles. The type of prevalent fuel directly influences the behavior of wildfire. Fuel is the only factor that can be modified by humans. The main fuel types in Merced County are crops and grasses, while there are also brush and pine fuels present in some areas in the southwest of the county. ● Topography—An area’s terrain and slopes affect its susceptibility to wildfire spread. Both fire intensity and rate of spread increase as slope increases due to the tendency of heat from a fire to rise via convection. The arrangement and types of vegetation throughout a hillside can also contribute to increased fire activity on slopes.
● Weather—Weather components such as temperature, relative humidity, wind, and lightning also affect the potential for wildfire. High temperatures and low relative humidity dry out fuels that feed wildfires, creating a situation where fuel will more readily ignite and burn more intensely. Thus, during periods of drought, the threat of wildfire increases. Wind is the most influential weather factor of the three and its influence can increase rates of spread regardless of temperature and relative humidity.

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Geographic Area
Both urban and wildland fires conditions exist in Merced County which increases the chances for damage to property, loss of life and/or injury. In the wildland-urban interface, where development has expanded into rural, higher risk areas, fires can result in major losses of property and structures. In most of Merced County, the California Department of Forestry and Fire Protection (CAL FIRE) ranks fuel loading as low.

Fuels are mainly crops and grasses. In the southwest corner, there are some brush, pine, and grass fuels, which are ranked as moderate fuel hazards, primarily in the area west of Interstate 5.

Generally, fire season in Merced County extends from early spring to late fall. Onset can happen suddenly due to lightning or human caused factors and wildfires can last from a few hours to a few months, but the likely hood of a large and damaging fire lasting for months in Merced County is not likely. Secondary effects from wildfire include increased erosion, destabilized slopes, degraded air and water quality, and economic impacts from burned landscapes. Urban fires primarily involve the uncontrolled burning of residential, commercial and/or industrial structures generally caused by human activities.

The California Department of Forestry and Fire Protection’s Fire and Resource Assessment Program (FRAP) assesses the amount and extent of California’s forests and rangelands, analyzes their conditions and identifies alternative management and policy guidelines.

CAL FIRE identifies areas that are at high risk of damage from wildfire based primarily on three factors:
● Ranking Fuel Hazards = ranking vegetation types by their potential fire behavior during a wildfire. ● Assessing the Probability of Fire = the annual likelihood that a large damaging wildfire would occur in a particular vegetation type.
● Defining Areas of Suitable Housing Density that Would Create Wildland-Urban Interface Fire Protection Strategy Situations = areas of intermingled wildland fuels and urban environments that are in the vicinity of fire threats.

Population density and the presence of structures are not currently used to determine the fire hazard severity for a particular region, although they do have a significant impact on fire behavior.

Based on the above criteria, CAL FIRE maps Fire Hazard Severity Zones for each county as “Very High,” “High,” or “Moderate”. As shown below in Figure 4-37, there are no areas in Merced County classified as Very High and the areas ranked High are primarily located west of Interstate 5. These areas exhibit the combination of vegetative fuel and topography that contribute to an increased fire hazard potential. The fact that an area is in a Moderate Hazard designation does not mean it cannot experience a damaging fire. It only means that the probability is reduced, generally because the number of days a year that the area has “fire weather” is less.

The Fire Hazard Severity Zones (FHSZ) spatial dataset was explicitly developed for adopting new ignitionresistant building code standards and adopted by the California Building Commission in 2007. It is constructed to describe the nature and probability of fire exposure to structures, including those lands that are highly urbanized, but in close proximity to open wildlands. It is broken into Federal Responsibility Areas, State Responsibility Areas, and Local Responsibility Areas shown below.

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Figure 4-37 Merced County Federal, State, and Local Responsibility Severity Zones CAL FIRE has also designated the following Merced County communities as being at increased risk from wildfires (https://osfm.fire.ca.gov/divisions/wildfire-planning-engineering/fire-plan/communities-at risk/):
● Dos Palos
● Gustine
● Los Banos
● South Dos Palos
Some unincorporated communities located within the county are not confronted with a high wildfire risk, due primarily to the dominant type of vegetation in those areas. The low-growing native grasses and shrubs found in these communities present a minimal vegetative fuel source and a corresponding low wildfire risk. In addition, the topography of those areas is mainly level and well developed in both residential and agricultural land uses.

Extent (Magnitude/Severity)
Vegetation (or fuel) plays a major role in fire behavior and shaping fire hazard potential. Vegetation distribution throughout the county varies by location and topography, with dramatic differences observed between the western, central, and eastern portions of the county. For instance, fire behavior in brush fuel

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types produces higher flame lengths than that in grassland, although spread rates are typically slower. Fire behavior in forests is variable, depending on surface fuel conditions and the presence of ladder fuels.

Fuel loading in developed areas susceptible to wildfire becomes even more complex. The introduction of some ornamental plantings as landscaping and groundcover can dramatically increase the fire loading of a neighborhood. Gazebos, fencing, patios, decks and even the structures themselves add even more fuel.

Once structures become involved in fire, the problem compounds as embers cast out thousands of feet onto combustible roofs well removed from the wildland area.

Steep terrain also plays a key role in the rate at which wildfires spread, as fires will normally burn much faster uphill. Generally, when the gradient of a slope doubles, the rate of spread of a fire will also double.

Steep topography also channels air flow, thereby creating erratic wind patterns. Fire suppression in steep areas is also complicated by limited accessibility, and the effectiveness of firefighters and equipment are hampered by lack of access roads.

Another factor that can increase the severity of wildfires in the county is areas with high percentages of dead trees, as discussed in subsection 4.3.15 Agricultural Pests and Disease.

The Fire Rating System defined in Table 4-66 describes the characteristics and potential intensity of fires, including the effect on the ability to manage and suppress fires. Fire conditions up through Class 5 are possible in Merced County, primarily in the unincorporated areas in the far east and west of the county.

Table 4-67 Fire Danger Rating System
Rating Basic Description Detailed Description
CLASS 1: Low Danger (L)
COLOR CODE: Green
fires not easily
started
Fuels do not ignite readily from small firebrands. Fires in open or cured grassland may burn freely a few hours after rain, but wood fires spread slowly by creeping or
smoldering and burn in irregular fingers. There is little danger of spotting.

CLASS 2: Moderate Danger
(M) COLOR CODE: Blue
fires start easily and
spread at a
moderate rate
Fires can start from most accidental causes. Fires in open cured grassland will burn briskly and spread rapidly on windy days. Woods fires spread slowly to moderately fast.

The average fire is of moderate intensity, although heavy concentrations of fuel – especially draped fuel -- may burn hot. Short-distance spotting may occur but is not
persistent. Fires are not likely to become serious and
control is relatively easy.

CLASS 3: High Danger (H)
COLOR CODE: Yellow
fires start easily and
spread at a rapid
rate
All fine dead fuels ignite readily, and fires start easily from most causes. Unattended brush and campfires are likely to escape. Fires spread rapidly, and short-distance spotting is common. High-intensity burning may develop on slopes
or in concentrations of fine fuel. Fires may become serious and their control difficult, unless they are hit hard and fast while small.

CLASS 4: Very High Danger
(VH) COLOR CODE: Orange
fires start very easily
and spread at a very
fast rate
Fires start easily from all causes and immediately after ignition, spread rapidly and increase quickly in intensity.

Spot fires are a constant danger. Fires burning in light fuels may quickly develop high-intensity characteristics - such as long-distance spotting - and fire whirlwinds, when they burn into heavier fuels. Direct attack at the head of such fires is rarely possible after they have been burning more than a few minutes.

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Rating Basic Description Detailed Description
CLASS 5: Extreme (E) COLOR
CODE: Red
fire situation is
explosive and can
result in extensive
property damage
Fires under extreme conditions start quickly, spread
furiously and burn intensely. All fires are potentially serious. Development into high-intensity burning will
usually be faster and occur from smaller fires than in the Very High Danger class (4). Direct attack is rarely possible and may be dangerous, except immediately after ignition.

Fires that develop headway in heavy slash or in conifer stands may be unmanageable while the extreme burning
condition lasts. Under these conditions, the only effective and safe control action is on the flanks, until the weather changes or the fuel supply lessens.

Source: http://www.wfas.net
Major wildland fires can completely destroy ground cover. If heavy rains follow a major fire, flash floods, heavy erosion, land subsidence and mudflows can occur. After a wildland fire passes through an area, the land is laid bare of its protective vegetation cover and is susceptible to excessive runoff and erosion from winter storms. The intense heat from the fire can also cause a chemical reaction in the soil that makes it less porous, and the fire can destroy the root systems of shrubs and grasses that aid in stabilizing slope material. These cascading effects can have ruinous impacts on people, structures, infrastructure, and agriculture.

Fire threat provides a measure of fuel conditions and fire potential in the ecosystem, representing the relative likelihood of “damaging” or difficult to control wildfire occurring for a given area. Fire Threat is not a risk assessment by itself but can be used to assess the potential for impacts on various assets and values susceptible to fire. Impacts are more likely to occur and/or be of increased severity for the higher threat classes. Fire threat is a combination of two factors: 1) fire probability, or the likelihood of a given area burning, and 2) potential fire behavior (hazard). These two factors are combined to create five threat classes ranging from low to extreme. Figure 4-38 below shows the wildfire threat areas throughout Merced County.

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Figure 4-38 Merced County Wildfire Threat Areas
Previous Occurrences
There have not been any state or federal disaster declarations in Merced County related to wildfire in the past. The Planning Team noted that although there are many fire starts, the fuels are “flashy” and fires are usually quickly put out. Despite this, there have been 101 wildfires recorded in the county from 1950-2018 totaling 110,893 acres burned. This is an average of over 1,500 acres burned every year. In 2020, a portion of the SCU Lightning Complex Fire, which is the 3rd largest fire by acres burned in state history, extended into Merced County, burning approximately 3,800 acres in the planning area. As stated above, most fires are relatively small compared to the state as a whole, the highest number of acres burned in the county was 19,131 during the 1996 Mercy fire. The county’s fire history from 1911-2020 is illustrated in Figure 4-39.

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Figure 4-39 Merced County Fire History, 1911-2020
Probability of Future Occurrences
Fire starts are highly likely during each fire season; though, they rarely result in large-scale wildfires in Merced County. Information obtained from the CAL FIRE Redbook lists multiple fires, the largest in the most recent past consumed approximately 3,800 acres. Based on climate and weather in Merced County and the fuels, topography, and a past fire history which indicates an average of 1.5 wildfires per year, it is likely that fires will continue to occur in the future. Figure 4-40 below shows the annual probability for wildfire in Merced County from 2026-2040, based on CAL FIRE GIS mapping.

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Figure 4-40 Merced County Annual Probability of Fire, 2026-2050 Climate Change Considerations
According to the 2018 California SHMP, climate change has the potential to impact the frequency, size, and severity of the wildfire hazard statewide. Increasing temperatures may intensify wildfire threat and susceptibility to more frequent wildfires in the county.

Exactly how climate change will affect total precipitation is not clear, but models suggest that there is a tendency for wetter conditions in the northern part of the state and drier conditions in the south (California Natural Resources Agency 2018a). Forests are also sensitive to variable precipitation events, as the 2012-2017 drought contributed to widespread tree mortality as warmer temperatures stressed trees and made them more susceptible to pests and pathogens (California Natural Resources Agency 2018).

Studies noted in California’s Fourth Assessment report note climate change impacts on wind patterns may strongly affect forests, potentially serving as a trigger mechanism for conversion of forest to other types of vegetation (California Natural Resources Agency 2018).

Current scientific models expect all of California will be affected by increased numbers of forest fires with added intensity due to longer warmer seasons, reduced distribution of biodiversity, lack of moisture, changes in ecosystems, drought impacts (e.g. pest diseases and continued spread of invasive species), and other impacts in coming years. The extending of the wildfire season into winter months, coinciding with seasonal high wind patterns, has contributed to severe fires in recent years. Southern California

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experienced 29 wildfires in December of 2017 alone, and the deadliest and most destructive fire in California history, the Camp Fire, happened in November of 2018.

Vulnerability Assessment
Merced County vulnerability to wildfires varies, with some areas of the planning area being at greater risk than others as described further in this section. Generally, this hazard is a medium concern. High fuel loads in some areas of the planning area along with geographical and topographical features create the potential for both natural and human caused fires that can result in loss of life and property. These factors, combined with natural weather conditions common to the area, including periods of drought, low relative humidity, and periodic winds, can result in frequent and sometimes catastrophic fires. Even the relatively flat central parts of the county are not immune to fire; hot and sometimes windy weather combined with dry vegetation and a denser population can result in an increase in the number of ignitions.

Figure 4-41 through Figure 4-44 below are the result of a nationwide risk study from the United States Forest Service. These figures provide a perspective of wildfire risk and vulnerability compared to other CA counties. Populated areas in Merced County have, on average, greater risk to homes than 14% of counties in California. Populated areas in Merced County have, on average, greater wildfire likelihood than 18% of counties in California.

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Figure 4-41 Merced County Wildfire Likelihood
Source: USFS

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Figure 4-42 Merced County Wildfire Likelihood Compared to California Counties Source: USFS

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Figure 4-43 Merced County Wildfire Risk to Homes
Source: USFS

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Figure 4-44 Merced County Wildfire Risk to Homes Compared to California Counties Source: USFS
General Property
The potential impacts of wildfire on property include crop loss, injury and death of livestock and pets, and damage to infrastructure, homes and other buildings located throughout the wildfire risk area.

GIS was used to intersect the parcel boundaries with a master address point layer to obtain the number of buildings per parcel. Only parcels with improvement values greater than zero were used in the analysis, this method assumes that improved parcels have a structure of some type. This data was then overlaid on the Fire Threat Layer. For the purposes of this analysis, the wildfire hazard zone that intersected the address point was assigned as the hazard zone for the entire parcel. It was assumed that every parcel with an improved value greater than zero was developed in some way, thus only improved parcels and their values were analyzed.

An analysis of the value of those parcels – the improvement value plus estimated value of building contents – quantifies the potential losses from wildfires by severity zones. The results show that $3.7 billion worth of property and approximately 8,500 structures are exposed to fire risk countywide. The

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majority of these buildings are in moderate to low hazard areas. The unincorporated areas and the City of Los Banos make up the majority of this risk. Residential properties constitute more than half of both the number of parcels and the projected losses. The total values shown in these tables include both structure value and contents and can be used as an estimate of potential losses since wildfires typically result in a total loss.

Table 4-68 Wildfire Hazard Exposure –Property Summary by Jurisdiction and Fire Threat Zone Jurisdiction Building
Count
Very
High
Building
Count
High
Building
Count
Moderate
Building
Count
Low
Total
Building
Count
Improved
Value
Estimated
Content Value
Total Value
Atwater 0 1 276 303 580 $158,646,509 $82,890,947 $241,537,456 Gustine 0 0 57 97 154 $26,104,098 $13,904,591 $40,008,689 Livingston 0 0 59 171 230 $91,308,401 $67,612,796 $158,921,197 Los Banos 0 2 198 976 1,176 $328,297,798 $178,953,729 $507,251,527 Merced 0 1 257 364 622 $156,504,212 $99,657,587 $256,161,799 Unincorporated 108 462 1,605 3,659 5,834 $1,373,680,176 $1,148,731,537 $2,522,411,713 Total 108 466 2,452 5,570 8,596 $2,134,541,194 $1,591,751,186 $3,726,292,380 Source: CAL FIRE, Merced County Assessor, Wood GIS analysis Figure 4-45 Unincorporated Area Buildings in Fire Threat Classes Source: CAL FIRE, Merced County Assessor, Wood GIS analysis People
Wildland fires result in a high risk for personal injury, loss of life to inhabitants of the fire area and firefighters, and losses of structures and personal property. Wildfires in or near the WUI frequently require emergency evacuation and sheltering, often for many days. As is shown in Table 4-68 below, approximately 17,364 people in Merced County reside in FHSZ. This figure was derived by taking the total number of residential structures identified in the FHSZs and multiplying them by the average household size in the county based off of 2019 U.S. Census Bureau estimates. 2%
8%
27%
63%
Building Count Very High
Building Count High
Building Count Moderate
Building Count Low

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Table 4-69 Population at Risk to Fire Threat
Jurisdiction Population
Atwater 1,787
Gustine 399
Livingston 756
Los Banos 4,115
Merced 1,837
Unincorporated 8,469
Total 17,364
Source: Merced County, HIFLD, CAL FIRE, FRAP, U.S. Census Bureau, Wood GIS Analysis Other indirect impacts from wildfires on people are related to dense smoke from fires within the region.

Wildfires in the past three years have decreased the air quality throughout Merced County. Dense smoke poses a risk to both people with compromised health as well as those considered healthy. A study from the University of California San Diego found that wildfire smoke is more harmful to respiratory health in humans than pollution from cars (NPR 2021). Studies have also shown an increase in ambulance calls, hospital visits and an increase of people experiencing respiratory or cardiac emergencies (NPR 2020).

Critical Facilities and Infrastructure
Critical facilities are those community components that are most needed to withstand the impacts of disaster, as previously described in the Assets section. Wildfire impacts to critical facilities can include structural damage or destruction, risk to persons located within facilities, disruption of transportation, shipping, and evacuation operations, and interruption of facility operations and critical functions.

Critical facilities and infrastructure also create an increased risk for the occurrence of wildfires. Overhead electric transmission lines have been known to spark wildfires. According to data from the California Public Utilities Commission, the state’s three largest utility companies collectively reported 2,009 ignitions statewide between 2014-2017, including at least 50 in Merced County. Most of these instances were small, less than one acre in size, however these fires can grow rapidly under the right fire conditions. One such example is California’s deadliest wildfire, the 2018 Camp Fire in Northern California. Identifying critical facilities and infrastructure and mitigating their potential risks is important both for maintaining the county’s resilience and for reducing the potential impacts of wildfire. The locations of critical facilities identified by HIFLD throughout the county are summarized by their exposure the various wildfire threat levels in Table 4-69 through Table 4-72 below.

Table 4-70 Critical Facilities Within the Low Wildfire Threat by Jurisdiction and FEMA Lifeline Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Atwater 1 2 1 - - 1 1 6
Dos Palos - - - - - - - 0
Gustine - - - - - 1 1 2
Livingston 2 - - - - - - 2

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Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Los Banos - - 1 - - 2 - 3
Merced - - 1 2 - 1 4 8
Unincorporated 20 18 2 3 - 17 156 216
Total 23 20 5 5 0 22 162 237
Source: Merced County, HIFLD, CAL FIRE, FRAP, Wood GIS Analysis Table 4-71 Critical Facilities Within the Moderate Wildfire Threat by Jurisdiction and FEMA Lifeline
Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Atwater - - - - - - 2 2
Dos Palos - - - - - - - 0
Gustine - - - - - 1 - 1
Livingston - - - - - - - 0
Los Banos - - - - - - - 0
Merced - - 1 - - 1 1 3
Unincorporated 10 10 - - - - 26 46
Total 10 10 1 0 0 2 29 52
Source: Merced County, HIFLD, CAL FIRE, FRAP, Wood GIS Analysis Table 4-72 Critical Facilities Within the High Wildfire Threat by Jurisdiction and FEMA Lifeline Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Atwater - - - - - - - 0
Dos Palos - - - - - - - 0
Gustine - - - - - - - 0
Livingston - - - - - - - 0
Los Banos - - - - - - - 0
Merced - - - - - - - 0
Unincorporated 17 26 1 - - 1 24 69

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Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Total 17 26 1 0 0 1 24 69
Source: Merced County, HIFLD, CAL FIRE, FRAP, Wood GIS Analysis Table 4-73 Merced County Critical Facilities Within the Very High Wildfire Threat by Jurisdiction and FEMA Lifeline
Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Atwater - - - - - - - 0
Dos Palos - - - - - - - 0
Gustine - - - - - - - 0
Livingston - - - - - - - 0
Los Banos - - - - - - - 0
Merced - - - - - - - 0
Unincorporated 5 115 - - - - 4 124
Total 5 115 0 0 0 0 4 124
Source: Merced County, HIFLD, CAL FIRE, FRAP, Wood GIS Analysis According to the analysis conducted, there are over 200 critical facilities exposed to at least a moderate wildfire threat area. The highest rates of exposure to wildfire threat areas are facilities in the Energy and Transportation Lifeline categories, both of which are crucial for response and evacuations in the event of a significant fire.

Economy
The economic impacts of wildfire include loss of property, direct agricultural sector job loss, secondary economic losses to businesses in or near wildland resources like parks and national forests, and loss of public access to recreational resources. Fire suppression may also require increased cost to local and state government for water acquisition and delivery, especially during periods of drought when water resources are scarce.

Effects on agriculture can be significant, which makes up a large portion of Merced County’s economy. In addition to the obvious impacts on crops and animals, wildland fire can have damaging effects on soil and water that will impact agriculture for an extended period of time.

Historic, Cultural, and Natural Resources
The County has 15 sites listed on the NRHP, and 28 listed on the California Register of Historical Resources. Since these structures are sensitive in nature and may not have been built according to the latest building codes due to their age, it is expected that they might be at risk of wildfires (e.g. because of their potential inability to withstand significant heat). Most of these structures are located in the Cities of

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Merced and Los Banos, which are at lower risk to wildfire than unincorporated areas of the county.

However, parks and open spaces, particularly in the foothills in the eastern edge of the county, could also be at risk of a wildfire. This area is the region’s gateway to Yosemite National Park, which is a significant historic, cultural, and natural resource for the entire state of California.

Future Development
Any population increases in the Planning Area will continue to make wildfire vulnerability a growing issue, especially as future development expands into higher fire risk areas. These risks can however be managed with strong land use regulations and building code requirements, and with policies established in the Health and Safety Element of the 2030 General Plan. For example, policies requiring fire-resistant vegetation, clustered development, and vegetation clear zones in areas with high and extreme fire hazard.

Risk Summary
The overall significance of wildfire in Merced County is Medium. These events are recurring in nature and can cause significant damage, loss of life, and disruption to critical infrastructure. ● The county experiences an average of one wildfire every 1.5 years and an average of 1,500 acres burned per year. As impacts of climate change such as increased temperatures and prolonged drought conditions continue in coming years, this frequency and intensity may increase. ● Powerlines and vehicle or equipment use present a significant source of ignitions. ● Effects on people: Past wildfires in the county have not resulted in a large number of fatalities; however, significant evacuations and sheltering have been required in past events. ● Effects on property: Wildfires can destroy homes, businesses, and critical infrastructure. $3.7 billion worth of property in the County is located in a Fire Threat Zone. ● Effects on critical facilities and infrastructure: Wildfires can disrupt access to, or even destroy critical facilities and infrastructure.
● Effects on economy: Wildfires impacts can include loss of property, direct agricultural sector job loss, secondary economic losses to businesses, and loss of public access to recreational resources. ● Effects on Historic, Cultural, and Natural Resources: Wildfire can significantly impact water and air quality, even at great distances from the area burning. Damage to agriculture, natural resource areas, and habitats are very likely during a wildfire.
● Related Hazards: Drought, Agricultural Pest Infestation and Plant Disease, Landslide and Debris Flow.

Table 4-74 Hazard Summary - Wildfire
Jurisdiction Geographic
Extent
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Significant Likely Limited Medium
City of Atwater Significant Highly Likely Negligible Medium City of Dos Palos Limited Highly Likely Negligible Medium City of Gustine Limited Occasional Critical Low
City of Livingston Limited Occasional Negligible Low
City of Los Banos Significant Highly Likely Negligible Medium City of Merced Limited Highly Likely Negligible Medium

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4.2.13Hazardous Materials Incidents
Hazard/Problem Definition
Generally, a hazardous material is a substance or combination of substances which, because of quantity, concentration, or physical, chemical, or infectious characteristics, may either cause or significantly contribute to, an increase in mortality or an increase in serious, irreversible, or incapacitating reversible, illness. Hazardous materials may also pose a substantial present or potential hazard to human health or environment when improperly treated, stored, transported, disposed of, or otherwise managed.

Hazardous material incidents can occur while a hazardous substance is stored at a fixed facility, or while the substance is being transported along a road corridor or railroad line or via an enclosed pipeline or other linear infrastructure.

The U.S. Department of Transportation (DOT), U.S. Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration all have responsibilities relating to the transportation, storage, and use of hazardous materials and waste. The Right to Know Network (RTK NET), maintained by the EPA’s National Response Center, is a primary source of information on the use and storage of hazardous materials, as well as data regarding spills and releases. The California Environmental Protection Agency and Department of Toxic Substances Control are authorized by the U.S. EPA to enforce and implement federal hazardous materials laws and regulations within the state. At the local level, Merced County’s Department of Public Health, Division of Environmental Health is the approved CUPA responsible for administration of permitting, inspections, and enforcement for hazardous waste and hazardous materials programs. The CUPA administers the Hazardous Material Business Plan (HMBPs), California Accidental Release Prevention (Cal-ARP) program, and the Aboveground Storage Act, as well as permitting and inspection activities for hazardous waste generators, and onsite hazardous waste treatment facilities, and underground storage tanks.

Hazardous materials can be divided into the following classes:
● Explosives
● Compressed gases: flammable, non-flammable compressed, poisonous ● Flammable liquids: flammable (flashpoint below 141 degrees Fahrenheit), combustible (flashpoint from 141 - 200 degrees)
● Flammable solids: spontaneously combustible, dangerous when wet ● Oxidizers and organic peroxides
● Toxic materials: poisonous material, infectious agents ● Radioactive material
● Corrosive material: destruction of human skin, corrodes steel It is also common to see hazardous materials releases as escalating incidents resulting from other hazards such as floods, wildfires, and earthquakes. The release of hazardous materials can greatly complicate or even eclipse the response to the natural hazards disaster that caused the spill.

The Safety Element of the Merced County General Plan contains goals, policies, and implementation measures pertaining to hazardous materials, including radioactive materials and pesticides. Merced County also has an Emergency Operations Plan which contains provisions to address hazardous materials incidents, such as establishing a Hazardous Materials Unit Leader within the Operations Section and to establish response operations in the event of an incident involving hazardous materials (Merced County Emergency Operations Plan 2017).

Geographic Area
Hazmat incidents can occur at a fixed facility or during transportation.

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Fixed Facilities
Hazardous materials facilities are identified and mapped by the counties they are located in, along with the types of materials stored there; facilities generally are located in and around developed areas. The Merced County Office of Emergency Services administers the Emergency Planning and Community Rightto-Know program for the planning area. Under Chapter 6.95 of the California Health and Safety Code and the Federal Resource Conservation and Recovery Act, any business storing quantities of hazardous materials greater than 55 gallons of liquid, 500 pounds of solid or 200 cubic feet of some compressed gases must file a HMBP annually that establishes incident prevention measures, hazardous material handling protocols and emergency response and evacuation procedures.

The EPA requires facilities containing certain extremely hazardous substances to generate Risk Management Plans (RMPs) and resubmit these plans every five years. According to the RTK NET, as of April 2021 there are 16 RMP facilities located in the County, as shown below in Figure 4-46.

The California Accidental Release Prevention Program (CalARP) is a statewide initiative to reduce the likelihood and severity of consequences of extremely hazardous materials releases. CalARP requires certain facilities (referred to as "stationary sources") which handle specified chemicals (termed "regulated substances") to take specified actions to proactively prevent and prepare for chemical accidents. Because the CalARP program is implemented at the local government level by the CUPAs, they can work directly with regulated facilities.

Figure 4-46 RMP Identified Hazardous Materials Facilities in Merced County

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Transportation
In transit, hazardous materials generally follow major transportation routes, including road, rail and pipelines, creating a risk area immediately adjacent to these routes. The county’s transportation network, primarily Interstate 5, and State Highways 33, 59, 99, 140, 152, and 165, all have the potential for hazardous material incidents. Railroad lines and airports may also transport hazardous materials. The Hazardous Materials and Waste section of the Merced County General Plan Health and Safety Element establishes policies requiring that the transportation of all hazardous materials through the county be coordinated with the CHP (Merced County General Plan, 2013).

Hazardous materials releases can also result from natural disasters, such as floods or earthquakes that may cause containment systems to fail or affect transportation infrastructure. In summary, hazardous material incidents have the potential to occur in business and industrial areas (where fixed facilities are located) and along transportation corridors. Hazardous material incidents can also occur in agricultural areas; these types of facilities typically use pesticides, fertilizers, and other agricultural chemicals that are harmful to people and the environment. For example, agricultural pesticides and fertilizers are often transported daily around the planning area. Illegal drug operations and dumping sites have also been known to pose a hazardous materials threat.

Lastly, information provided by the National Pipeline Mapping System (NPMS) indicate several pipelines conveying gas or hazardous liquids cross the planning area, these are shown in Figure 4-47 and primarily travel north-south in the vicinity of Interstate 5 and Highway 99. Pipelines ruptures can result in major spills, or even explosions like the ones in San Bruno in 2010, and Fresno in 2015.

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Figure 4-47 National Pipeline Mapping System, Merced County Pipelines Extent (Magnitude/Severity)
Hazardous materials come in the form of explosives, flammable and combustible substances, poisons and radioactive materials. Hazards can occur during production, manufacturing, storage, transportation, use, or disposal. Impacts from hazardous materials releases can include:
● Fatalities
● Injury
● Evacuations
● Property damage
● Animal fatalities (livestock, fish & wildlife)
● Air pollution
● Surface or ground water pollution/contamination
● Interruption of commerce and transportation
Numerous factors influence the impacts of a hazardous materials release, including the type and quantity of material, location of release, method of release, weather conditions, and time of day. This makes it

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difficult to predict precise impacts. The impact to life and property from any given release depends primarily on:
● The type and quantity of material released.
● The human act(s) or unintended event(s) necessary to cause the hazard to occur. ● The length of time the hazard is present in the area. ● The tendency of a hazard, or that of its effects, to either expand, contract, or remain confined in time, magnitude, and space.
● Characteristics of the location and its physical environment that can either magnify or reduce the effects of a hazard.

CalFire notes several additional factors that can contribute to the impact of hazardous materials releases from a fixed facility or transportation incident:
● Solid, liquid, and/or gaseous hazardous materials can be released from fixed or mobile containers either accidentally or on purpose.
● The resulting release can last for hours or for days. ● The substances released may be corrosive or otherwise damaging over time, and they may cause an explosion and/or fire.
● Contamination may be carried out of the incident area by people, vehicles, water, and/or wind. ● Weather conditions will directly affect how the hazard develops. ● The micrometeorological effects of buildings and terrain can alter travel and duration of agents. ● Shielding in the form of sheltering in place can protect people and property from harmful effects. ● Noncompliance with fire and building codes as well as failure to maintain existing fire protection and containment features can substantially increase the damage from a hazardous materials release.

The release or spill of hazardous materials can also require different emergency responses depending on the amount, type, and location of the spill incident.

As noted above, the County contains a number of facilities that store and use significant quantities of hazardous materials. Additionally, a variety of hazardous materials are transported through the County by highway, rail, and pipelines, all of which are potentially vulnerable to accidental spills. Consequences can vary depending on whether the spill affects a populated area versus an unpopulated but environmentally sensitive area.

Potential losses can vary greatly for hazardous material incidents. For even a small incident, there are cleanup and disposal costs. In a larger scale incident, cleanup can be extensive and protracted. There can also be deaths or injuries requiring doctor’s visits and hospitalization, disabling chronic injuries, soil and water contamination can occur, necessitating costly remediation. Evacuations can disrupt home and business activities. Large-scale incidents can easily reach $1 million or more in direct damages, with cleanups that can last for years.

Previous Occurrences
Merced County experiences multiple hazardous materials incidents every year. The vast majority of these incidents are minor with very localized impacts.

Table 4-74 breaks down 973 hazardous materials incidents reported to the California OES Warning Center from 2006 through 2021 based on location; this works out to an average of approximately 65 incidents per year. Even this total likely excludes a large number of unreported minor spills. 380 of these incidents occurred in transit, 381 occurred at a fixed location, and the remaining 211 had no location specified.

These hazardous material spills consisted of varying quantities of chemicals, petroleum, gasoline, sewage, and other materials. While the number of incidents can vary considerably from year to year, the average

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number of hazardous materials spills or accidents in the County has trended upwards over the past 15 years. This is in line with the statewide trend, which has seen hazardous materials incidents increase by 30 percent during the same time period.

These incidents include both transportation and fixed facility incidents. This list in no way captures all hazardous material spills within the County, only those that were significant enough to be reported to Cal OES. The data indicates that hazardous materials incidents can occur across the county with a greater frequency in the more developed areas.

Table 4-75 Hazardous Materials Incidents in Merced County by Location, 2006-2021 Location Incidents Location Incidents
Merced 281 Delhi 15
Unknown 183 Winton 14
Atwater 81 EL Nido 11
Santa Nella 70 Le Grand 11
Unincorporated 67 Dos Palos 10
Los Banos 62 Planada 10
Livingston 55 Stevinson 9
Hilmar 36 Snelling 5
Gustine 29 Cressey 4
Ballico 17 Tuttle 1
Source: CalOES Spill Release Reporting
The vast majority of these hazardous materials incidents have only minimal life safety impacts. One event in July 2019 resulted in one death and nine hospitalizations after a chemical spill in Los Banos.

Another database maintained by the U.S. Coast Guard reports 205 incidents recorded in Merced County, with 13 of them resulting in confirmed injuries from 1998 to 2013, with 32 individuals injured. There have also been 7 confirmed fatalities in the county from 2000 to 2019. Some incidents may also result in temporary evacuations, closures of transportation routes, or damage to facilities. This translates to roughly 6% of incidents resulting in injuries and 3% resulting in a fatality.

The Toxic Release Inventory (TRI) is a resource for learning about toxic chemical releases and pollution prevention activities by industrial and federal facilities. Section 313 of the Emergency Planning and Community Right-to-Know Act created the TRI program. According to the TRI database, there were 13 facilities within the County in 2019 that have collectively produced or managed approximately 9.6 million pounds of waste (US EPA 2021). These facilities dispose, treat, recover, and recycle various types of waste and chemicals and ultimately “release” the waste or chemicals into the air or water, or some form of land disposal.

Probability of Future Occurrences
Highly Likely - As discussed above, the County experiences an average of 65 hazardous materials incidents per year, with various degrees of impact; there is effectively a 100 percent chance that the County will see a hazardous materials incident in any given year. However, hazardous materials incidents that cause deaths, injuries, or evacuations are far rarer, occurring in between 3 and 6% of occurrences on average. These can occur at any time and with little predictability given the presence of major transportation routes in throughout the County.

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Climate Change Considerations
There are no known effects of climate change on human caused hazards, such as hazardous material incidents. However, it is possible that an increase in other hazards, such as severe storms and fire events may increase the likelihood of an accidental hazardous materials release.

Vulnerability Assessment
General Property
The impact of a fixed hazardous facility, such as a chemical processing facility is typically localized to the property where the incident occurs. The impact of a small spill (i.e. liquid spill) may also be limited to the extent of the spill and remediated if needed. A blanket answer for potential impacts is hard to quantify, as different chemicals may present different impacts and issues. Property within a half mile in either direction of designated hazardous materials routes are at increased risk of impacts. While cleanup costs from major spills can be significant, they do not typically cause significant long-term impacts to property.

People
Hazardous materials incidents can cause injuries, hospitalizations, and even fatalities to people nearby.

People living near hazardous facilities and along transportation routes may be at a higher risk of exposure, particularly those living or working downstream and downwind from such facilities. For example, a toxic spill or a release of an airborne chemical near a populated area can lead to significant evacuations and have a high potential for loss of life.

In addition to the immediate health impacts of releases, a handful of studies have found long-term health impacts such as increased incidence of certain cancers and birth defects among people living near certain chemical facilities. However there has not been sufficient research done on the subject to allow detailed analysis.

Social Vulnerability
While hazardous material incidents could take place anywhere across the County and may be unpredictable, those living near HazMat facilities or along transportation routes that additionally happen to be socially vulnerable communities would be of highest concern. Based on a combination of the SoVI data presented and discussed in subsection 4.2.1 and the presence of major transportation routes and EPA or CalARP regulated facilities the most vulnerable populations include Merced, Atwater, and Livingston. In addition, agricultural farm workers are most vulnerable to pesticide exposure and other hazardous material incidents associated with the agricultural operation.

Critical Facilities and Infrastructure
Impacts of hazardous material incidents on critical facilities are most often limited to the area or facility where they occurred, such as at a transit station, airport, fire station, hospital, or railroad. However, they can cause long-term traffic delays and road closures resulting in major delays in the movement of goods and services. These incidents would be more severe if they result in traffic delays on road closures on any of the designated truck routes or hazardous materials routes in the County. These impacts can spread beyond the planning area to affect neighboring counties, or vice-versa. While cleanup costs from major spills can be significant, they do not typically cause significant long-term impacts to critical facilities.

Economy
The primary economic impact of hazardous material incidents result in lost business, delayed deliveries, property damage, and potential contamination. Large and publicized hazardous material-related events can deter tourists and recreationists too. If incidents occur along major transportation corridors, they can

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temporarily close routes and result in traffic delays. Economic effects from major transportation corridor closures can be significant.

Historic, Cultural, and Natural Resources
Hazardous material incidents may affect a small area at a regulated facility or cover a large area outside such a facility. Widespread effects occur when hazards contaminate the groundwater and eventually the municipal water supply, or they migrate to a major waterway or aquifer. Impacts on wildlife and natural resources can also be significant. These types of widespread events may be more likely to occur during a transportation incident, such as a pipeline spill, and can have far reaching and devastating impacts on the natural environment and habitats if they occurred near one of the several wildlife refuges in Merced County.

Future Development
The amount of hazardous materials that are stored, used, and transported across the County are inferred to continue to increase over the next five years based on regional growth trends. As discussed previously, the number of hazardous materials incidents in the County has generally been increasing year to year for the last 15 years and is likely to continue to increase. Future development is also expected to increase the number of people potentially exposed to the impacts of hazardous materials incidents.

Risk Summary
The overall significance of hazardous materials incidents in Merced County is Medium. These incidents occur frequently with little to no warning, both at fixed sites and along transportation routes throughout the County. The possibility of a major spill impacting a major populated area exists; historically the impacts of these incidents on the County as a whole have been fairly limited. ● Over the past 15 years, the County experienced an average of 65 hazardous materials incidents per year. This number has generally been trending higher in recent years. Incidents that caused death or injuries were far rarer.
● Of the 972 hazardous material incidents over the past 15 years, 39 percent were transportation related, 39 percent occurred at fixed facilities; the remaining 22 percent have an unreported location. ● Several pipelines conveying gas or hazardous liquids cross the County, as shown in the NPMS. ● Hazardous materials releases can complicate response to and recovery from natural disasters such as floods and earthquakes.
● Hazardous Materials incidents can cause injuries and fatalities, as well as long-term health problems like increased cancer risks.
● Impacted properties can require cleanup, but the effects are usually localized to the site of the release. ● Extended road closures can result in economic losses and impact tourism. ● Impacted facilities and infrastructure can require cleanup, but the effects are usually localized to the site of the release.
● Related Hazards include Earthquake, Flood, Fire.

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Table 4-76 Hazard Summary – Hazardous Materials Incidents Jurisdiction Geographic
Extent
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Limited Highly Likely Negligible Low
City of Atwater Limited Occasional Negligible Medium
City of Dos Palos Limited Occasional Negligible Medium
City of Gustine Significant Unlikely Critical Low
City of Livingston Limited Occasional Negligible Medium City of Los Banos Significant Likely Critical Medium
City of Merced Limited Likely Negligible Medium

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4.2.14Cyber Attack
Hazard Problem/Definition
The 2018 California SHMP defines cyber attacks as “attempts by cyber criminals to attack a government, organization, or private party by damaging or disrupting a computer or computer network, or by or stealing data from a computer or computer network for malicious use.” Cyber-attacks use malicious code to alter computer operations or data. The vulnerability of computer systems to attacks is a growing concern as people and institutions become more dependent upon networked technologies. The Federal Bureau of Investigation reports that, “cyber intrusions are becoming more commonplace, more dangerous, and more sophisticated,” with implications for private- and public-sector networks. Cyber threats can take many forms, including:

Phishing attacks: Phishing attacks are fraudulent communications that appear to come from legitimate sources. Phishing attacks typically come through email but may come through text messages as well.

Phishing may also be considered a type of social engineering meant to exploit employees into paying fake invoices, providing passwords, or sending sensitive information.

Malware attacks: Malware is malicious code that may infect a computer system. Malware typically gains a foothold when a user visits an unsafe site, downloads untrusted software, or may be downloaded in conjunction with a phishing attack. Malware can remain undetected for years and spread across an entire network.

Ransomware: Ransomware typically blocks access to a jurisdiction’s/agency’s/ business’ data by encrypting it. Perpetrators will ask for a ransom to provide the security key and decrypt the data, although many ransomware victims never get their data back even after paying the ransom.

Distributed Denial of Service (DDoS) attack: Perhaps the most common type of cyber attack, a DDoS attack seeks to overwhelm a network and causes it to either be inaccessible or shut down. A DDoS typically uses other infected systems and internet connected devices to “request” information from a specific network or server that is not configured or powerful enough to handle the traffic.

Data breach: Hackers gaining access to large amounts of personal, sensitive, or confidential information has become increasingly common in recent years. In addition to networked systems, data breaches can occur due to the mishandling of external drives.

Critical Infrastructure/SCADA System attack: There have been recent critical infrastructure Supervisory Control and Data Acquisition (SCADA) system attacks aimed at taking down lifelines such as power plants and wastewater facilities. These attacks typically combine a form of phishing, malware, or other social engineering mechanisms to gain access to the system.

The 2018 California SHMP states: “Nationally, cybersecurity incidents such as financial fraud and government database breaches have increased from 5,503 in 2006 to 67,168 in 2014.” This is more than a 1200% increase in occurrence over just an 8-year period. As this trend continues and society and government functions become ever more technologically dependent, this hazard is of increasing concern.

In one recent attempt to combat this threat, the State of California adopted Senate Bill 327 in September of 2018. This bill seeks to improve information privacy, specifically pertaining to connected devices.

Existing laws in California require businesses to take all reasonable steps to dispose of customer records within their custody containing personal information and also require businesses that own, license, or maintain personal information about a California resident to implement and maintain reasonable security procedures. SB 327, which went into effect January 1, 2020 further requires the manufacturer of connected devices to equip the device with a reasonable security feature to protect user information (Senate Bill 327).

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Geographic Area
Cyber attacks can and have occurred in every location regardless of geography, demographics, and security posture. Incidents may involve a single location or multiple geographic areas. A disruption can have far reaching effects beyond the location of the targeted system; disruptions that occur far outside the state can still impact people, businesses, and institutions within the county. All of Merced County is potentially susceptible to cyber attacks, making the geographic extent significant.

Extent (Magnitude/Severity)
There is no universally accepted scale to explain the severity of cyber attacks. The strength of a DDoS attack is often explained in terms of a data transmission rate. One of the largest DDoS disruptions ever, the October 21, 2016 Dyn attack, peaked at 1.2 terabytes per second and impacted some of the internet’s most popular sites that included Amazon, Netflix, PayPal, Twitter, and several news organizations.

Data breaches are often described in terms of the number of records or identities exposed. The Privacy Rights Clearinghouse, a nonprofit organization based in San Diego, maintains a database of data breaches in the United States. The largest data breach ever reported occurred in August 2013, when hackers gained access to all three billion Yahoo accounts. This incident is associated with California in the Privacy Rights Clearinghouse database as the company is headquartered in Sunnyvale, California. As the location of the headquarters of many large tech businesses and server farms, California as a state is potentially a greater target for cyber attacks. There have been many other instances in the state where millions of records have been breached.

Ransomware attacks are typically described in terms of the amount of ransom requested, or by the amount of time and money spent to recover from the attack. One report from cybersecurity firm Emsisoft estimates the average successful ransomware attack costs $81 million and can take organizations 287 days to recover. Overall, the potential magnitude of a cyber attack can be seen as limited due to the lack of deaths and injuries, but the economic costs can be significant.

Previous Occurrences
The cybersecurity firm Symantec reports there were a total of 1,209 data breaches worldwide in 2016.

While the number of breaches has remained relatively steady, the average number of identities stolen has increased to almost one million per incident. The report also found that one in every 131 emails contained malware, and the company’s software blocked an average of 229,000 web attacks every day.

California is by far the state with the highest number of data breaches. The Privacy Rights Clearinghouse database lists 1,338 data breaches against systems located in California, totaling over 5.7 billion impacted records; however, it is difficult to know how many of those affected Merced County residents. Attacks happening outside of the state can also impact local businesses, personal identifiable information, and credit card information.

A 2017 study found ransomware payments over a two-year period totaled more than $16 million. Even if a victim is perfectly prepared with full offline data backups, recovery from a sophisticated ransomware attack typically costs far more than the demanded ransom. However, according to a 2016 study by Kaspersky Lab, roughly one in five ransomware victims who pay their attackers never recover their data.

Recent years have seen an increase in ransomware attacks, particularly against local government systems.

The City of Atlanta was hit by a major ransomware attack in 2018, recovery from which wound up costing a reported $2.6 million, significantly more than the $52,000 ransom demand. A similar attack against the City of Baltimore in 2019 affected the city government’s email, voicemail, property tax portal, water bill, and parking ticket payment systems, and delayed more than 1,000 pending home sales. In March 2019,

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Orange County, North Carolina was attacked with a ransomware virus, causing slowdowns and service problems at key public offices such as the Register of Deeds, the Sheriff’s Office, and county libraries. The attack impacted a variety of county services, including disrupting the county’s capability to process real estate closings, issue marriage licenses, process fees or permits, process housing vouchers, and verify tax bills. Each of these past events are examples of the range of risks posed to county and municipal governments by various cyber attacks.

Reports of successful attacks against SCADA systems are less common. In February 2021, a hacker gained system access to a water treatment plant in Oldsmar, Florida and increased the levels of sodium hydroxide to dangerous levels; however, this change was immediately detected by plant staff and corrected.

A large, sophisticated malware attack, known as Olympic Destroyer, was launched against the 2018 Winter Olympics in PyeongChang, South Korea. The attack initially took down servers, email, Wi-Fi, and ticketing systems, which could have severely disrupted the games. Fortunately, the organizing committee had a robust cybersecurity group that was able to quickly restore most functions.

Probability of Future Occurrences
Small-scale cyber attacks such as DDoS attacks occur daily, but most have negligible impacts at the local or regional level. Data breaches are also extremely common, but again most have only minor impacts on government services.

Perhaps of greatest concern to Merced County are ransomware attacks, which are becoming increasingly common. It is difficult to predict the odds of Merced County being hit with a successful ransomware attack in any given year, but it is safe to say it is likely to be attacked in the coming years.

The possibility of a larger disruption affecting systems within the County is a constant threat, but it is difficult to quantify the exact probability due to such highly variable factors as the type of attack and intent of the attacker. Major attacks specifically targeting systems or infrastructure in the County cannot be ruled out.

Climate Change Considerations
There are no known effects of climate induced impacts on cyber attacks.

Vulnerability Assessment
The impact of a cyber attack can vary depending on the type of attack and the intent of the malicious actor. Though a cyber disruption can have limited impacts within a system’s own operations, it may cause cascading impacts.

General Property
The vast majority of cyber attacks affect only data and computer systems and have minimal impact on general property.

People
Injuries or fatalities from cyber attacks would generally only be possible from a major cyber terrorist attack against critical infrastructure, such as potable water treatment and delivery systems. If such an event would occur it could indirectly impact the customers served by water utility. More likely impacts to the public are financial losses and an inability to access systems such as public websites and permitting sites. Indirect impacts could include interruptions to traffic control systems or other infrastructure

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Data breaches and subsequent identify thefts can have huge impacts on the public. The Internet Crime Complaint Center (IC3) estimates that identity theft alone resulted in $2.7 billion in losses to businesses and $149 million in losses to individuals.

According to the Cyber & Infrastructure Security Agency (CISA), cyber risks to 9-1-1 systems can have “severe impacts, including loss of life or property; job disruption for affected network users; and financial costs for the misuse of data and subsequent resolution.” CISA also compiled a recent list of attacks on 9- 1-1 systems including a DDoS in Arizona, unauthorized access with stolen credentials in Canada, a network outage in New York, and a ransomware attack in Baltimore.

Critical Facilities and Infrastructure
While the vast majority of cyber attacks affect only data and computer systems, sophisticated attacks against utilities and infrastructure sites have occurred. Such attacks typically target the SCADA systems of critical infrastructure, which can potentially result in system failures on a scale equal with natural disasters.

Facilities and infrastructure, such as the electrical grid, could become unusable as a result of a cyber attack. A cyber attack took down the power grid in Ukraine in 2015, leaving over 230,000 people without power. Agencies that rely on electronic backup of critical files are also vulnerable.

The delivery of services can be impacted since governments rely to a great extent upon electronic delivery of services. Most agencies rely on server backups, electronic backups, and remote options for Continuity of Operations or the Continuity of Government. Many departments in the participating jurisdictions have the option to move to a paper method including permitting, DMV services, payments to and from the county, and payroll. However, access to documents on the network, OneDrive access, and other operations that require collaboration across the County will be significantly impacted.

Loss of government servers due to a cyber attack could affect the ability of responders to do their jobs.

Cyber attacks can interfere with emergency response communications, access to mobile data terminals, and access to critical preplans and response documents.

The delivery of services can be impacted since governments rely, to a great extent, upon electronic delivery of services. An attack could raise questions regarding the security of using electronic systems for government services.

Economy
Economic impacts from a cyber attack can be debilitating. The cyber attack in 2018 that took down the City of Atlanta cost at least $2.5 million in contractor costs and an estimated $9.5 million additional funds to bring everything back online. The attack in Atlanta took “more than a third of the 424 software programs offline” and recovery lasted more than 6 months. A 2018 cyber attack on the Colorado Department of Transportation cost an estimated $1.5 million. None of these statistics take into account the economic losses to businesses and ongoing IT configuration to mitigate from a future cyber attack.

Historic, Cultural, and Natural Resources
The vast majority of cyber incidents have little-to-no impact on historic, cultural or natural resources. A major cyber terrorism attack could potentially impact the environment by triggering a release of a hazardous materials, or by causing an accident involving hazardous materials by disrupting traffic control devices.

Future Development
Changes in development have no impact to the threat, vulnerability, and consequences of a cyber attack.

Cyber attacks can and have targeted small and large jurisdictions, multi-billion-dollar companies, small

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mom-and-pop shops, and individual citizens. The decentralized nature of the internet and data centers means that the cyber threat is shared by all, regardless of new construction and changes in development.

Risk Summary
The overall significance of cyber attacks in Merced County is Medium. These incidents occur frequently, with California being the state with by far the most reported incidents. The possibility of an attack of any scale impacting the County is almost certain.
● There have been 1,338 data breaches statewide over a 14-year period, averaging approximately 96 incidents per year.
● Nationwide the increase in cyber attacks has been dramatic year over year. As this trend continues it is safe to assume there is a threat to Merced County.
● Injuries and fatalities to people are unlikely, unless in a widescale attack that affected infrastructure and resulted in indirect impacts on communities. People may also be impacted financially. ● The vast majority of attacks do not affect property.
● Economic impacts from a cyber attack can be debilitating, sometimes costing local governments millions of dollars.
● The vast majority of attacks target only computer systems, however sophisticated attacks against utilities and infrastructure, such as electrical grids, have occurred.

Table 4-77 Hazard Summary – Cyber Attack
Jurisdiction Geographic
Extent
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Significant Likely Critical Medium
City of Atwater Limited Occasional Negligible Medium
City of Dos Palos Limited Occasional Negligible Medium
City of Gustine Limited Unlikely Limited Low
City of Livingston Limited Occasional Negligible Medium City of Los Banos Significant Likely Negligible Medium
City of Merced Limited Occasional Negligible Low

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4.2.15 Agricultural Pests and Disease
Hazard/ Problem Description
Located in the Central San Joaquin Valley, Merced County’s farming and agricultural industry is ranked as the top agriculture-producing county in California and the country. Agriculture is the dominant land use in Merced County, accounting for more than 90% of all land. According to the Merced County Department of Agriculture, agriculture grossed more than 3 billion dollars in 2019. Top commodities since 2018 included milk, almonds, and cattle (see table below).

Table 4-78 Top 15 Commodities in Merced County in 2018
Rank Change since 2017 Crop 2019 Value Top 15 Share
1 -- Milk $905,116,000 31.3%
2 -- Almonds $421,254,000 14.6%
3 Increase Cattle and Calves $297,451,000 10.3%
4 Decrease Chickens $294,633,000 10.2%
5 -- Sweet Potatoes $234,946,000 8.1%
6 -- Tomatoes $126,790,000 4.4%
7 -- Silage – Corn $108,077,000 3.7%
8 Increase All Nursery Products $84,515,000 2.9%
9 Decrease Hay – Alfalfa $69,943,000 2.4%
10 Decrease Eggs, Chicken $64,668,000 2.2%
11 Increase Misc. Vegetables $60,709,000 2.1%
12 -- Grapes – Wine $56,748,000 2.0%
13 Decrease Cotton – Pima $45,799,000 1.6%
14 -- Turkeys $43,490,000 1.5%
15 Increase Pollination $41,284,000 1.4%
Top 15 Total $2,890,875,000
Source: 2019 Report on Agriculture
Agricultural pests and pathogens (insects, fungi, bacteria, viruses and invasive plants) cause injury or severe destruction to crops or livestock. From exotic fruit flies to noxious weeds, California’s agriculture can be impacted by a wide variety of invasive pests and pathogens. These pests pose significant threats to the state’s agricultural crops, farm workers, economy, food supply and native habitat. They can also result in increases in food prices for consumers. The number of invasive pests and pathogens newly detected in California and the rest of the United States has increased at alarming rates in recent years, and that trend is projected to continue into the future. Insect pests and diseases, such as bark beetles and Sudden Oak Death in trees can also destroy forests and oak woodland habitat located along the eastern and western perimeters of Merced County, which can in turn increase the fuel load and lead to greater fire risk.

Agricultural disasters could also occur due to severe weather events, such as extreme heat, freeze cycles, and heavy rainfall and these hazards are covered under subsections 4.3.6 through 4.3.10. Drought events are covered under subsection 4.3.2.

The California Food and Agricultural Code mandates pest prevention programs to prevent the introduction and spread of pests in California. These include the Pest Exclusion Program, Pest Detection Program, Pierce’s Disease Control Program, and Federal Phytosanitary Certificate Program. Target pests are listed in Table 4-70, but also include dairy, livestock, and poultry pests and diseases, such as Mycobacterium bovis and pathogenic avian influenzas. Animal agriculture, such as dairy farms also result in copious amounts of manure, which contain zoonotic pathogens, which are viruses, bacteria, and parasites of animal origin that cause disease in humans.

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Table 4-79 Target Pests in Merced County
Target Pest Insect Hosts Traps Placed
Asian Citrus Psyllid Citrus 620
European Pine Shoot Moth Pine Trees 3
Glassy-Winged Sharpshooter Nurseries/Urban
Areas
392
Light Brown Apple Moth Ornamental 288
Melon Fruit Fly Vegetable
Gardens
95 Oriental Fruit Fly Fruit Trees 320
European Corn Borer Corn 5
Gypsy Moth Shade Trees 107
Japanese Beetle Turf, Rose 100
Mediterranean Fruit Fly Fruit Trees 320
Mexican Fruit Fly Fruit Trees 169
Sweet Potato Weevil Sweet Potatoes 120
Source: 2019 Report on Agriculture
Geographic Area
According to the 2017 Census for Agriculture, Merced County contains almost 1 million agricultural acres.

Cropland accounts for 58% of agricultural land, while pastureland accounts for 38%. There are approximately 2,337 farms (as of 2017) in the County.

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Figure 4-48 Merced County Important Farmland
Extent (Magnitude/Severity)
Different pests can impact different crops in different ways; while there is no scale to define the extent of an infestation, a pest could have a major economic impact on the value of infested crops.

Another large factor that may influence crop yield is the spread of invasive plants, which may compete with crops for resources and in some cases also introduce pests. According to California Invasive Plant Council (Cal-IPC), invasive plants cost California $82 million every year in control, monitoring and outreach; estimated actual impacts can reach into the billions. Based on the USDA’s RMA Crop Indemnity Reports, between 2007 and 2019 (no losses were reported in 2020), there were 734.6 acres lost due to plant disease and insects and $256,962 indemnity payments made.

Past Occurrences
Based on information from the USDA, Merced County received several USDA disaster declarations since 1950 (see Table 4-3 above). All the declarations were associated with flood, drought or severe weather events, and most recently, the COVID-19 pandemic. None were related to agricultural disease.

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Probability of Future Occurrences
While probability of future occurrence is usually calculated based on past experience, different pests have different recidivism rates across the County. Based on past occurrences, pests and invasive species will continue to present a constant threat to the County and its jurisdictions.

Climate Change Considerations
California’s Fourth Climate Change Assessment (2018) notes that “climate change impacts terrestrial ecosystems and wildlife in multiple ways, including invasion by exotic species, prevalence of wildlife disease, and loss of native habitats.” Changing climate conditions can impact viable living areas of species and cause migration; shift the spread of pests and disease northward by changing habitat temperatures and making previously undesirable habitats welcoming for new species and lengthen habitable seasons (CNRA 2018a). Longer growing seasons may also allow agricultural pests to persist longer, which can increase the severity of infestations on agricultural operations. Further, weather events have become more numerous and more severe. Changes in weather patterns can also have dramatic impacts on the ecosystem, including agriculture systems, and more severe impacts can be expected into the future.

Vulnerability Assessment
General Property
Agricultural losses occur on an annual basis and are usually associated with severe weather events, including heavy rains, floods, hail, freeze, and drought. The State of California Multi-Hazard Mitigation Plan attributes most of the agricultural disasters statewide to drought, freeze, and insect infestations.

Other agricultural hazards include fires, crop and livestock disease, noxious weeds, and contamination of animal food and water supplies.

Infestation of agriculture pests could impact crop yields, potential destroying whole fields. Between 2015 and 2018, the RMA paid no indemnities due to damage from insects but paid $22,900 in indemnities due to damage from crop disease.

People
A widespread infestation of livestock and crops could severely impact the economic base of the County and its communities employed by the agriculture industry. According to the USDA 2017 Census of Agriculture, Merced County has 2,337 farms, which is a -6% change from the previous census in 2012.

While agricultural production in the County can enhance the economy and improve human health and ensure stable food prices in California and the U.S., certain habitats established for irrigation and agricultural output can also threaten human health by increasing the risk of vector-borne diseases (e.g. mosquitos, etc.). Rural communities, residing closest to these agricultural operations may also be most vulnerable to these diseases, as livestock pathogens are capable of infecting host species, which may include wildlife and human.

Jobs could be negatively impacted during an agriculture emergency; jobs tangentially tied to the agriculture industry could also be affected. According to “The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment”, rising temperatures and drought conditions due to climate change could also lead to increases in the occurrence and transport of pathogens in agricultural environments, which will increase the risk of food contamination and direct human exposure to pathogens and toxins (SGCRP 2016). In turn, this will increase health risks and require greater vigilance in food safety practices and regulation.

Disease can also exacerbate the impacts from other natural hazards. An example of this is adverse weather. Dead branches can be broken by high winds, and there are reports of these branches falling and causing harm to people.

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Social Vulnerability
Based on the SoVI data presented and discussed in subsection 4.2.1, the areas with the highest level of social vulnerability in the County are in the western and southeastern portion of the County, as well as some of the incorporated jurisdictions including Merced and Los Banos. These communities as well as those working in the agricultural sector would likely be impacted by the effects of agricultural hazards.

Critical Facilities
Critical facilities assessed in this plan would not be directly impacted by agricultural pests or diseases; however, the food and agriculture industry is considered critical infrastructure in Merced County and California. Impacts to this infrastructure, such as farms, diary operations, and processing facilities would have debilitating effects of food security, the economy, and public health and safety. Merced County farms and ranches, and the associated food processing facilities would be directly impacted economically by long-term disruptions in the food supply associated with crop losses due to agricultural pests and disease.

Economy
According to the University of California’s Center for Invasive Species Research, it has been estimated in California alone that invasive pests cost the state at least $3 billion per year. Nationally, it is estimated that invasive species cost the U.S. $138 billion per year. Economic impacts include both prevention, response and recovery costs. Given the contribution of agriculture to the local economy pest impacts could be significant. The value of agricultural commodities noted at the beginning of this hazard profile is $2,890,875,000. Based on that a hypothetical loss of 5% to due to agricultural pest or disease would equate to approximately $144M.

Historic, Cultural and Natural Resources
Invasive species typically harm native species through predation, habitat degradation and competition for shared resources; they can outcompete native species out of natural habitats and are a leading cause of population decline and extinction in animals.

Tree mortality raises the wildfire threat in healthy forests, increasing the vulnerability, strength, speed and destruction of fires in the area.

Future Development
Most likely, good development practices in the future would not have an impact on Merced County’s vulnerability to agricultural pests, plant diseases, marine invasive species or tree mortality.

Risk Summary
● Merced County’s farming and agricultural industry is ranked as the top agriculture-producing county in California and the country.
● Agriculture is the dominant land use in Merced County, accounting for more than 90% of all land, or almost 1 million acres.
● Invasive plants cost California $82 million every year in control, monitoring and outreach. ● Based on USDA disaster declarations since 1950, none were related to agricultural pests or disease. ● Changes in weather patterns can have dramatic impacts on the ecosystem, including agriculture systems, and more severe impacts associated with agricultural pests and disease can be expected into the future.
● Changing climate conditions can shift the spread of pests and disease northward by changing habitat temperatures and making previously undesirable habitats welcoming for new species through longer growing seasons. This may increase the severity of pest infestations on agricultural operations.

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● Related hazards: Drought
Table 4-80 Risk Summary – Agricultural Pests, and Disease Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Extensive Likely Critical Medium
City of Atwater Extensive Likely Critical Medium
City of Dos Palos Extensive Likely Critical Medium
City of Gustine Extensive Likely Critical Medium
City of Livingston Extensive Likely Critical Medium
City of Los Banos Extensive Likely Critical Medium
City of Merced Extensive Likely Critical Medium

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4.2.16Pandemics/Epidemics
Hazard/Problem Description
A pandemic can be defined as a disease that attacks a large population across great geographic distances.

Pandemics are larger than epidemics in terms of geographic area and number of people affected.

Epidemics tend to occur seasonally and affect much smaller areas. Pandemics, on the other hand, are most often caused by new subtypes of viruses or bacteria for which humans have little or no natural resistance. Consequently, pandemics typically result in more deaths, social disruption, and economic loss than epidemics.

There are three conditions that trigger a pandemic declaration:

1. A new virus subtype must emerge that has not previously circulated in humans (and therefore there is no pre-existing immunity),

2. This new subtype must be able to cause disease in humans, and

3. The virus must be easily transmissible from human-to-human.

Since March 2020, Merced County, the nation, and the world are dealing with the COVID-19 pandemic (caused by the SARS-CoV-2 virus), confirming that pandemic is a key public health hazard in the planning area. This hazard risk assessment includes an analysis of pandemic risk across Merced County and an analysis of the impacts of the hazards profiled in this plan on public health.

Unlike seasonal flu, a pandemic has much greater potential for loss of life and significant social disruption due to higher rates of transmission and more severe health impacts. The SARS-CoV-2 virus has a much higher rate of transmission than the seasonal flu, primarily by airborne transmission of droplets/bodily fluid. Common symptoms include fever, cough, fatigue, shortness of breath or breathing difficulties, and loss of smell and taste. While most people have mild symptoms, some people develop acute respiratory distress syndrome with roughly one in five requiring hospitalization in the United States and a fatality rate between 1 to 2 percent. Because the virus can be transmitted by people who are asymptomatic, and due to the presence of several variants of SARS-CoV-2, containing the spread has been a significant challenge across the globe.

Geographic Area
Pandemics occur not only on a county or state level, but on a national and global scale. It is likely that most communities in Merced County would be affected, either directly or by secondary impacts. Some indirect consequences may be the diversion of resources that may be otherwise available.

Merced County has reported 31,009 cases and 448 deaths from COVID-19 as of April 11, 2021. According to the Merced County Public Health COVID-19 dashboard, the City of Merced has the highest number of cases (approximately 11,100 as of April 12, 2021, and the City of LeGrand Planada and City of Hilmar have the lowest number of cases in the 700-800 range) as of April 9, 2021. This is likely because cities like Merced have higher populations and municipal areas relative to other cities within the county, and COVID-19 is transmitted primarily from human-to-human contact.

Another example of a human health hazard that is endemic to Merced County is Valley Fever, or “cocci” which is a known, but poorly understood secondary effect of drought conditions, and possibly a combination of wind and drought events followed by a rainy season. Valley Fever is an infection caused by a fungus (Coccidioides immitis) that lives in soil and dirt and in areas with low rainfall, high summer temperatures, and moderate winter temperatures. Valley Fever is primarily a disease of the lungs that is common in the southwestern United States and northwestern Mexico. Valley Fever derives its name from

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its discovery in the San Joaquin Valley of California. While the extent of Valley Fever varies from southwestern United States, northern Mexico, and some parts of Central and South America, the known endemic area in California include portions of the Sacramento Valley, all of the San Joaquin Valley, and desert regions and southern portions of California. Individuals are likely to be affected by Valley Fever if they live in an area where the cocci fungus is prevalent.

Extent (Magnitude/Severity)
The magnitude of a public health emergency will range significantly depending on the transmissivity and mortality rate of the virus. For example, pandemic influenza is easily transmitted from person-to-person, however advances in medical technologies have greatly reduced the number of deaths caused by influenza over time.

Today, a much larger percentage of the world’s population is clustered in cities, making them ideal breeding grounds for epidemics. Additionally, the explosive growth in air travel means the virus could spread around the globe within hours. Under such conditions, there may be very warning little time for counties, states, and countries to prepare. Most experts believe we will have just one to six months between the time that a dangerous new influenza strain is identified and the time that outbreaks begin to occur in the United States. Outbreaks are expected to occur simultaneously throughout much of the nation, preventing shifts in human and material resources that normally occur with other natural disasters.

These and many other aspects make pandemics unlike any other public health emergency or community disaster. Pandemics typically last for several months to 1-2 years and have even longer lasting effects on the economy and communities.

As described by the World Health Organization (WHO), the Pandemic Intervals Framework is a six-phased approach to defining the progression of a pandemic. This framework is used to guide pandemic planning and provides recommendations for risk assessment, decision making, and action. These intervals provide a common method to describe pandemic activity which can inform public health actions. The duration of each pandemic interval might vary depending on the characteristics of the virus and the public health response.

The six-phase approach was designed for the easy incorporation of recommendations into existing national and local preparedness and response plans. Phases 1 through 3 correlate with preparedness in the pre-pandemic interval, including capacity development and response planning activities, while Phases 4 through 6 signal the need for response and mitigation efforts during the pandemic interval. Phase 6 was reached in the County during the 2020 COVID outbreak.

Pre-Pandemic Interval
Phase 1 is the natural state in which influenza viruses circulate continuously among animals but do not affect humans.

Phase 2 involves cases of animal influenza that have circulated among domesticated or wild animals and have caused specific cases of infection among humans.

Phase 3 represents the mutation of the animal influenza virus in humans so that it can be transmitted to other humans under certain circumstances (usually very close contact between individuals). At this point, small clusters of infection have occurred.

Pandemic Interval
Phase 4 involves community-wide outbreaks as the virus continues to mutate and become more easily transmitted between people (for example, transmission through the air).

Phase 5 represents human-to-human transmission of the virus in at least two countries.

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Phase 6 is the pandemic phase, characterized by community-level influenza outbreaks.

Past Occurrences
● Since the early 1900s, five lethal pandemics have swept the globe:
● 1918-1919 Spanish Flu: The Spanish Flu was the most severe pandemic in recent history. The number of deaths was estimated to be 50-100 million worldwide and 675,000 in the United States. Its primary victims were mostly young, healthy adults. At one point, more than 10 percent of the American workforce was bedridden.
● 1957-1958 Asian Flu: The 1957 Asian Flu pandemic killed 1 to 2 million people worldwide, including about 70,000 people in the United States, mostly the elderly and chronically ill. Fortunately, the virus was quickly identified, and vaccine production began in May 1957. ● 1968-1969 H3N2 Hong Kong Flu: The 1968 Hong Kong Flu pandemic killed 34,000 Americans.

Again, the elderly were more severely affected. This pandemic peaked during school holidays in December, limiting student-related infections, which may have kept the number of infections down.

Also, people infected by the Asian Flu ten years earlier may have gained some resistance to the new virus.
● 2009-2010 H1N1 Swine Flu: This influenza pandemic emerged from Mexico in early 2009 and was declared a public health emergency in the U.S. on April 26. By June, approximately 18,000 cases had been reported in the U.S. and the virus had spread to 74 countries. Most cases were fairly mild, with symptoms similar to the seasonal flu, but there were cases of severe disease requiring hospitalization and a number of deaths. The CDC estimates that 43-89 million people were infected worldwide, with an estimated 8,870 to 18,300 H1N1 related deaths, including 12,469 deaths in the United States. ● 2020-Ongoing COVID-19: The COVID-19 or novel coronavirus outbreak began in December 2019 and was declared a pandemic in March of 2020. As of April 11, 2021, over 136 million cases and approximately 2.9 million deaths have been reported globally, according to the WHO. Within the U.S. as of April 11, 2021, over 30 million cases and over 555,000 deaths have been reported. Merced County has reported 31,009 cases so far resulting in 448 deaths. COVID-19 vaccines are currently being administered and thus far almost 15% of Merced County adults (18 years or older) have been fully vaccinated. It will take several months for the entire population to receive a vaccine and achieve herd immunity; additionally, due to the uncertainty in the transmission of several variants of the SARS-CoV-2 virus, the pandemic is expected to continue through 2021.

Probability of Future Occurrences
Even before the COVID-19 pandemic began, most public health experts considered another major pandemic to be inevitable. However, there is no definite way to predict when the next pandemic might occur. Some indicators will be present, but not every new virus turns into a pandemic. Based on the five pandemics that have affected the United States in roughly the last 100 years, a pandemic occurs on average roughly every 20 years.

Climate Change Considerations
Additional research is needed to determine the effects of climate change on the frequency and duration of epidemics and pandemics. Climate change may influence vector-borne disease transmission, although the direction of the effects (increased or decreased incidence) will be location- and disease-specific. The intensity and extent of certain diseases is projected to increase. According to the WHO, there has been research development into the linkages between climate and infectious disease transmission that examine the associations between climate variability and infectious disease occurrence, early indicators of emerging infectious disease impacts of climate change and using predictive models to estimate the future burden of infectious disease under different climate change scenarios (WHO 2003). In summary, future

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risks associated with climate change are difficult to predict, but changes in infectious disease transmission patterns are likely consequences of climate change. Climate change can impact when and where pathogens appear, particularly related to temperature and rainfall patterns.

Ongoing efforts to reduce greenhouse gas emissions, building climate resiliency, and creating robust public health campaigns to prevent or prepare for possible increased vector-borne diseases may help to reduce the impacts of climate change on pandemics.

Vulnerability Assessment
Preparing for, responding to, and recovering from a pandemic requires a strategy that includes a holistic suite of public health activities designed to lessen the impact on morbidity and mortality. These activities include education, vaccination, prophylaxis, isolation/quarantine, a robust contact tracing program, and the closure of public facilities. In addition, clear, concise communication with the public and with other agencies remains a critical component, as does the ability of the involved agencies to achieve collaboration and coordination. By their very nature, most pandemics, once started, will not be stopped until they have run their course. This course can be shortened and weakened by a number of factors, with vaccination being the most effective method for protecting the population. Pandemic plans describe strategies of preparedness, response, and recovery to attempt to decrease illnesses and deaths during the pandemic period to manageable levels (i.e., that do not overwhelm the critical infrastructures of the State), and to promote community resiliency and rapid recovery.

General Property
For the most part, property itself is not generally impacted by a human disease epidemic or pandemic.

However, as concerns about contamination increase, property may be quarantined or destroyed as a precaution against spreading illness. Additionally, traditional sheltering facilities including homeless shelters or temporary facilities set up to support displaced persons due to an evacuation or other reason due to a simultaneous disaster occurring cannot be done in a congregate setting. This requires additional planning considerations or use of facilities that allow for non-congregate shelter settings, which may require an approval of a request to FEMA for non-congregate sheltering, and may have an increased cost (such as the use of individual hotel rooms) as opposed to traditional congregate sheltering facilities.

People
Pandemics have the ability to affect large segments of the population for long periods of time. The number of hospitalizations and deaths will depend on the virulence of the virus. Risk groups cannot be predicted with certainty; the elderly, people with underlying medical conditions, and young children are usually at higher risk due to their higher exposure rates from schools, but as discussed above this is not always true for all infectious agents. People without health coverage or access to good medical care are also likely to be more adversely affected. Mental health of the public could also be impacted depending on the length of the event and public health guidance on prevention.

As previously described in the Past Events section above, the COVID-19 pandemic has resulted in over 555,000 deaths in the U.S. alone (448 in Merced County). In addition to the direct impacts, the pandemic has completely disrupted life for many people. Most large gatherings have had to be cancelled, and many schools have closed. Sheltering in place and social distancing have been highly encouraged and, in some places, mandated, leaving some individuals isolated for months.

Social Vulnerability
Preparing for, responding to, and recovering from a pandemic requires a strategy that includes a holistic suite of public health activities designed to lessen the impact on morbidity and mortality. These activities include education, vaccination, prophylaxis, isolation/quarantine, a robust contact tracing program, and

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the closure of public facilities. In addition, clear, concise communication with the public and with other agencies remains a critical component, as does the ability of the involved agencies to achieve collaboration and coordination. By their very nature, most pandemics, once started, will not be stopped until they have run their course. This course can be shortened and weakened by a number of factors, with vaccination being the most effective method for protecting the population. Pandemic plans describe strategies of preparedness, response, and recovery to attempt to decrease illnesses and deaths during the pandemic period to manageable levels (i.e., that do not overwhelm the critical infrastructures of the State), and to promote community resiliency and rapid recovery.

Critical Facilities
In the event of a pandemic, especially one with high transmission rates and mortality rates such as COVID19, community lifelines, such as healthcare facilities, like hospitals will be heavily affected and may be overwhelmed due to limited number of beds, doctor and medical staff, laboratory testing capacity, and possible personal protective equipment (PPE) shortages. Indirect impacts can also result in these facilities being temporarily offline due to testing or other precautionary monitoring and downed systems. Further, outbreaks in small cities and counties may cause medical facilities to reach capacity very quickly. Other critical facilities and infrastructure are not directly affected by a pandemic but may have difficulty maintaining operations and maintenance activities due to a significantly decreased workforce. Schools may also be forced to close.

Economy
Pandemics can have extensive economic impacts, as evidenced by the COVID-19 pandemic and associated restrictions on social gatherings. Social distancing requirements have affected nearly every segment of the local and national economy, most notably the restaurant and hospitality industries.

Additionally, tourism may be impacted in affected areas. As a result, the unemployment rate can increase, which also occurred in 2020 due to the COVID-19 pandemic. Other economic impacts including varying disruptions in the food supply chains and other essential medical services.

Historic, Cultural and Natural Resources
Impacts to these resources are typically minimal. However, reduced tourism during outbreaks could lead to additional economic impacts.

Future Development
Population growth and development contribute to pandemic exposure. Future development in and around Merced County has the potential to change how infectious diseases spread through the community and impact human health in both the short and long-term. New development may increase the number of people and facilities exposed to public health hazards and greater population concentrations (often found in special needs facilities, businesses, and school campuses) put more people at risk. During a disease outbreak those in the immediate isolation area would have little to no warning, whereas, the population further away in the dispersion path may have some time to prepare and mitigate against disease depending on the hazard, its transmission, and public notification.

Risk Summary
● Pandemics affecting the U.S. occur roughly once every 20 years but cannot be reliably predicted. ● Effects on people will vary, but a significant portion of the population could become ill, and may need to be hospitalized
● Effects on property are typically minimal, although quarantines could result in short-term closures.

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● Community lifelines, such as healthcare facilities, like hospitals will be impacted and may be overwhelmed and have difficulty maintaining operations due to bed availability, medical staffing shortages, and lack of PPE and other supplies.
● Lost productivity due to illness and potential business closures could potentially have severe economic impacts, such as increased unemployment rates in the County. Social distancing requirements and fear of public gatherings could also significantly reduce in person commerce. ● The hazard is considered high significance across all participating jurisdictions. ● Ongoing mitigation activities should focus on disease prevention, especially during flu season. This includes, but is not limited to, pre-season community outreach campaigns to educate the public about risks and available support; establishing convenient vaccination centers; reaching out to vulnerable populations and care givers; and issuing advisories and warnings.

Table 4-81 Hazard Risk Summary – Pandemics/Epidemics
Jurisdiction Geographic Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Merced County Extensive Occasional Catastrophic High
City of Atwater Extensive Occasional Catastrophic High
City of Dos Palos Extensive Occasional Critical Medium
City of Gustine Extensive Occasional Catastrophic High
City of Livingston Extensive Occasional Catastrophic High City of Los Banos Extensive Occasional Catastrophic High City of Merced Extensive Occasional Critical Medium

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5 MITIGATION STRATEGY
Requirement §201.6(c)(3):
[The plan shall include the following:] A mitigation strategy that provides the jurisdiction’s blueprint for reducing the potential losses identified in the risk assessment, based on existing authorities, policies, programs, and resources, and its ability to expand on and improve these existing tools.

This section describes the mitigation strategy process and mitigation action plan for the Merced County MJHMP. It describes how the County and participating jurisdictions met the requirements for the following from the 10-step planning process:
● Planning Step 6: Set Goals
● Planning Step 7: Review Possible Activities
● Planning Step 8: Draft an Action Plan
The mitigation strategy reflects the results of the collaborative work of the HMPT. Subsection 5.3 Mitigation Action Plan is based on the updated planning process, risk assessment, capability assessment, goal setting, and the identification of mitigation actions. Taking all of these into consideration, the HMPT developed the following overall mitigation strategy:
● Communicate the hazard information collected and analyzed through this planning process as well as HMPT success stories so that the community better understands what can happen where and what they themselves can do to be better prepared.
● Implement the action plan recommendations of this plan. ● Use existing rules, regulations, policies, and procedures already in existence. Given the flood hazard in the planning area, an emphasis should be placed on continued compliance with the NFIP. ● Monitor multi-objective management opportunities so that funding opportunities may be shared and packaged, and broader constituent support may be garnered.

5.1 Mitigation Goals and Objectives
§201.6(c)(3)(i)
[The hazard mitigation strategy shall include a] description of mitigation goals to reduce or avoid long‐ term vulnerabilities to the identified hazards.

Up to this point in the planning process, the HMPT has organized resources, assessed hazards and risks, and documented mitigation capabilities. The resulting goals, objectives, and mitigation actions were developed based on these tasks. The HMPT held a series of meetings and exercises designed to achieve a collaborative, updated mitigation strategy as described further throughout this section.

Over a series of meetings during the 2021 update process the HMPT reviewed the results of the hazard identification, vulnerability assessment, and capability assessment update. This analysis of the risk assessment identified areas where improvements could be made and provided the framework for the HMPT to update planning goals and objectives and the ultimate mitigation strategy for the Merced County planning area.

Goals were defined for the purpose of this mitigation plan as broad-based public policy statements that:
● Represent basic desires of the community;

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● Encompass all aspects of community, public and private; ● Are nonspecific, in that they refer to the quality (not the quantity) of the outcome; ● Are future-oriented, in that they are achievable in the future; and ● Are time-independent, in that they are not scheduled events.

Goals are stated without regard to implementation. Implementation cost, schedule, and means are not considered. Goals are defined before considering how to accomplish them so that they are not dependent on the means of achievement. Goal statements form the basis for objectives and actions that will be used as means to achieve the goals. Objectives define strategies to attain the goals and are more specific and measurable.

During the 2021 plan update process, HMPT members review the existing goals and objectives as well the goals and objectives from 2018 State of California Hazard Mitigation Plan and from the 2014 City of Merced LHMP. Through a brainstorming process at their third meeting, the HMPT identified a variety of possible goals and then came to a consensus on seven main sets of goals and objectives. Goals 4, 5 and 6 are new to 2021 plan update; other revisions included removing the word “natural” from the goals to be more inclusive to all hazards. Following the development of goals, the HMPT also identified specific objectives to achieve each goal. Goals and objectives are listed below, but are not prioritized:
● Goal 1: Reduce the potential for loss of life and injury from hazards - Assist vulnerable populations from the impacts of severe weather by organizing a mechanism for outreach.
- Educate property owners by increasing wildfire awareness and measures for reducing risks - Identify opportunities to reduce losses associated with High Hazard potential dams ● Goal 2: Minimize or reduce damage to property.
- Minimize growth and development in hazard areas
- Adopt and enforce building codes
- Educate property owners by increasing wildfire awareness and measures for reducing risks - Identify opportunities to reduce losses associated with High Hazard potential dams ● Goal 3: Build resiliency and redundancy to maintain essential services, lifelines, facilities, and infrastructure.
- Ensure protection and enhancement of key emergency access routes - Protect critical facilities and infrastructure to minimize loss of critical services - Seek funding sources and partners for future mitigation activities - Improve organizational capabilities to address health and safety issues in mitigation and response
● Goal 4: Minimize impacts of hazards to agriculture and the economies of communities. - Encourage water conservation measures among urban, rural, and agricultural users - Increase water storage to mitigate flooding and drought - Strengthen disaster resistance and resiliency of major employers - Develop plans for post-disaster recovery
● Goal 5: Protect and leverage natural and beneficial mitigation functions of the environment. - Encourage the use of drought tolerant or xeriscaping practices into landscape ordinances - Incorporate defensible space in landscaping of new and existing development ● Goal 6: Promote hazard mitigation as an integrated policy.

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- Promote hazard mitigation as integrated policy among communities in the county and with the region and state
- Incorporate flood mitigation into local planning by adoption of post-disaster recovery ordinance based on a plan to regulate repair activity
- Continue to improve enforcement of existing standards and regulations ● Goal 7: Increase public awareness of hazards.
- Promote education and awareness about natural hazards risk, mitigation, and preparedness to citizens, public agencies, elected officials, nonprofit organizations, and businesses - Develop water saving education program
- Increase communication regarding hazard mitigation among communities in the county

5.1.1 Continued Compliance with the National Flood Insurance Program (NFIP) The NFIP makes federally backed flood insurance available to homeowners, renters, and business owners in participating communities. For most participating communities, FEMA has prepared a detailed Flood Insurance Study. The study presents water surface elevations for floods of various magnitudes, including the 1% annual chance flood (or 100-year flood) and the 0.2% annual chance flood (or 500-year flood).

Base flood elevations and the boundaries of the 100- and 500-year floodplains are shown on Flood Insurance Rate Maps (FIRM), which are the principal tools for identifying the extent and location of the riverine flood hazard. FIRMs are the most detailed and consistent data source available, and for many communities they represent the minimum area of oversight under their floodplain management program.

Participants in the NFIP must, at a minimum, regulate development in floodplain areas in accordance with NFIP criteria. Before issuing a permit to build in a floodplain, participating jurisdictions must ensure that three criteria are met:
● New buildings and those undergoing substantial improvements must, at a minimum, be elevated to protect against damage by the 100-year flood.
● New floodplain development must not aggravate existing flood problems or increase damage to other properties.
● New floodplain development must exercise a reasonable and prudent effort to reduce its adverse impacts on threatened salmonid species.

Merced County, Atwater, Dos Palos, Livingston, Los Banos and Merced participate in the NFIP. Structures permitted or built in the county before 1979 when the County, Atwater and Merced joined the NFIP (1978 for Dos Palos and Livingston and 1998 for Los Banos) are called “pre-FIRM” structures, and structures built afterwards are called “post-FIRM.” Post-FIRM structures built in compliance with the floodplain regulations are mitigated to withstand floods up through the 100-year event. The insurance rate is different for the two types of structures, as pre-FIRM structures are at higher risk of flooding. The effective date for the current countywide FIRM is December 2, 2008. The County and participating jurisdictions are currently in good standing with the provisions of the NFIP. Compliance is monitored by FEMA regional staff. Maintaining compliance with the NFIP is an important component of flood mitigation and risk reduction.

The City of Gustine is not a participant in the NFIP and has been sanctioned since December 2, 2009. This means that residents are not able to obtain flood insurance from the NFIP. The City has minimal flood risk and the effective FEMA flood hazard mapping does not show any Special Flood Hazard Area (SFHA) or 1% annual chance flooding within city limits. This has been the reason for not joining the NFIP, but as part of this plan update the City will revisit the cost and benefit of joining, including working with CA DWR and FEMA to understand the implications of the sanction designation. Refer to the mitigation strategy in

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Section 5 for more information on specific mitigation actions related to addressing the sanction designation.

Given the flood hazard and risk in the planning area and recognizing the importance of the NFIP in mitigating flood losses, an emphasis is placed on continued compliance with the NFIP by Merced County and all NFIP participating jurisdictions including Atwater, Dos Palos, Livingston, Los Banos and Merced. As NFIP participants, these communities have and will continue to make every effort to remain in good standing with NFIP. This includes continuing to comply with the NFIP’s requirements for adopting official FEMA floodplain maps and maintaining, enforcing, and updating local floodplain regulations.

5.2 Identification and Analysis of Mitigation Actions
§201.6(c)(3)(ii):
[The hazard mitigation strategy shall include a] section that identifies and analyzes a comprehensive range of specific mitigation actions and projects being considered to reduce the effects of each hazard, with particular emphasis on new and existing buildings and infrastructure. All plans approved by FEMA after October 1, 2008, must also address the jurisdiction’s participation in the NFIP, and continued compliance with NFIP requirements, as appropriate.

In order to identify and select mitigation measures to support the mitigation goals, each hazard identified in Section 4: Hazard Identification and Risk Assessment was evaluated. The HMPT analyzed a comprehensive set of viable mitigation alternatives for both new and existing buildings and infrastructure that would support identified goals and objectives. Each HMPT member was provided with the following list of categories of mitigation measures, which originate from the NFIP CRS:
● Prevention: Administrative or regulatory actions or processes that influence the way land and buildings are developed and built.
● Property protection: Actions that involve the modification of existing buildings or structures to protect them from a hazard or remove them from the hazard area. ● Structural: Actions that involve the construction of structures to reduce the impact of a hazard. ● Natural resource protection: Actions that, in addition to minimizing hazard losses, also preserve or restore the functions of natural systems.
● Emergency services: Actions that protect people and property during and immediately after a disaster or hazard event.
● Public information/education and awareness: Actions to inform and educate citizens, elected officials, and property owners about the hazards and potential ways to mitigate them.

At the mitigation strategy meeting the HMPT was also provided with a matrix showing examples of potential mitigation action alternatives for each of the above categories, for each of the identified hazards.

The HMPT was also provided a handout that explains the categories and provided further examples.

Another reference document titled “Mitigation Ideas” developed by FEMA in 2013 and FEMA’s 2020 “Mitigation Action Portfolio” were distributed to the HMPT via an online link. These document lists the common alternatives for mitigation by hazard and actions funded by FEMA. The HMPT was also instructed to consider both future and existing buildings in considering possible mitigation actions. This reference provides four categories of mitigation actions that were discussed at the HMPT meeting in addition to the NFIP/CRS categories. These include:
● Plans and Regulations
● Structure and Infrastructure Projects
● Education and Awareness

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● Natural systems protection
Other alternatives discussed in the webinar include the four ‘A’s’ of mitigation:
● Alter the physical nature of the hazard
- Such as wildfire defensible space and fuels treatments, snow fences etc. ● Avert the hazard away from people, buildings, and infrastructure - Can include engineered solutions, drainage, and channel improvements, floodproofing, fuel breaks
● Adapt to the hazard
- Through land use planning, building codes and design standards, warning systems etc. ● Avoid the hazard
- Natural systems protection, open space, acquisition, or relocation of properties out of hazardous areas
As part of the review of mitigation options long-term climate change adaptation strategies were also discussed. HMPT members were encouraged to incorporate climate change adaptation measures into the mitigation strategy of their respective jurisdictions utilizing resources and guidance available on the CalAdapt website.

To facilitate the brainstorming process, the HMPT referred to a matrix of typical mitigation alternatives organized by CRS category for the hazards identified in the plan, in addition to a handout that explains the categories and provided examples. These materials are included in Appendix B. HMPT members were encouraged to develop mitigation alternatives that would protect future, as well as existing, development from hazards per the DMA 2000 regulations. A facilitated discussion then took place to examine the existing actions in the 2014 plan and analyze the other possible mitigation alternatives. With an understanding of the alternatives, a brainstorming session was conducted to generate a list of preferred mitigation actions. The result was new and updated project ideas with the intent of meeting the identified goals and mitigating identified hazards.

These new and updated project actions were expanded on during a fourth HMPT meeting scheduled to focus on the refinement and prioritization of new mitigation activities. During the fourth HMPT meeting, Wood facilitated a discussion on the draft MJHMP and any remaining information or mitigation gaps that needed to be addressed. During the fourth HMPT meeting the group also discussed opportunities for plan integration and reviewed the plan implementation and maintenance procedures.

5.2.1 Prioritization Process
Once the mitigation actions were identified, the HMPT was provided with several decision making tools, including FEMA’s recommended prioritization criteria, STAPLEE, to assist in deciding why one recommended action might be more important, more effective, or more likely to be implemented than another. STAPLEE stands for the following:
● Social: Does the measure treat people fairly? (e.g., different groups, different generations) Does it consider social equity, disadvantaged communities, or vulnerable populations? ● Technical: Will it work? (Is the action technically feasible? Does it solve the problem?) ● Administrative: Is there capacity to implement and manage the project? (adequate staffing, funding, and other capabilities to implement the project?)
● Political: Who are the stakeholders? Did they get to participate? Will there be adequate political and public support for the project?
● Legal: Does the jurisdiction have the legal authority to implement the action? Is it legal? Are there liability implications?

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● Economic: Is the action cost-beneficial? Is there funding available? Will the action contribute to the local economy?
● Environmental: Does the action comply with environmental regulations? Will there be negative environmental consequences from the action?
In accordance with the Disaster Mitigation Act requirements, an emphasis was placed on the importance of a benefit-cost analysis in determining action priority. Other criteria used to assist in evaluating the benefit-cost of a mitigation action included:
● Does the action address hazards or areas with the highest risk? ● Does the action protect lives?
● Does the action protect infrastructure, community assets or critical facilities? ● Does the action meet multiple objectives (Multiple Objective Management)? ● What will the action cost?
● What is the timing of available funding?
The mitigation categories, multi-hazard actions, and criteria are included in Appendix D: Mitigation Categories and Alternatives.

At the mitigation strategy webinar, the HMPT reviewed and discussed the STAPLEE considerations to determine which of the identified actions were most likely to be implemented and effective. Prioritization of previous mitigation actions identified in the 2014 HMP that were carried forward in the updated plan were revisited during the fourth HMPT meeting. New actions identified in 2021 also were prioritized based on the group discussion. With the STAPLEE criteria in mind, HMPT participants were given a set of three green sticky dot stickers. The team was asked to use the dots to prioritize projects with the above criteria in mind, essentially voting on the projects. The projects with the most dots became the higher priority projects. This process provided both consensus and priority for the recommendations.

The process of identification and analysis of mitigation alternatives allowed the HMPT to come to consensus and to collectively prioritize recommended mitigation actions. During the voting process, emphasis was placed on the importance of a benefit-cost review in determining project priority; however, this was not a quantitative analysis. Benefit-cost was considered in greater detail in the development of the Mitigation Action Plan. For example, parameters were established for assigning subjective ratings (high, medium, low) to the benefits and costs of each mitigation action. Specifically, each action developed for this plan contains a description of the problem and proposed project, the entity with primary responsibility for implementation, any other alternatives considered, a cost estimate, expected project benefits, potential funding sources, and a schedule for implementation. Development of these project details for each action led to the determination of an overall high, medium, or low priority for each action.

Recognizing the limitations in prioritizing actions from multiple departments and the regulatory requirement to prioritize by benefit-cost to ensure cost-effectiveness, the HMPT decided to pursue mitigation action strategy development and implementation according to the nature and extent of damages, the level of protection and benefits each action provides, political support, project cost, available funding, and jurisdiction and department priority. This process guided the development of a prioritized action plan for Merced County and the participating jurisdictions.

Cost-effectiveness will be considered in greater detail through a formal benefit-cost analysis when seeking FEMA mitigation grant eligibility and funding (e.g. HMGP, PDM grant programs) for eligible actions associated with this plan.

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5.3 Mitigation Strategy Action Plan
§201.6(c)(3)(iii)
[The hazard mitigation strategy shall include an] action plan, describing how the action identified in paragraph (c)(3)(ii) of this section will be prioritized, implemented, and administered by the local jurisdiction. Prioritization shall include a special emphasis on the extent to which benefits are maximized according to a cost benefit review of the proposed projects and their associated costs. §201.6(c)(3)(iv)
For multi‐jurisdictional plans, there must be identifiable action items specific to the jurisdiction requesting FEMA approval or credit of the plan.

This action plan was developed to present the recommendations developed by the HMPT for how the Merced County planning area can reduce the vulnerability of people, property, infrastructure, and natural and cultural resources to future disaster losses. Over time the implementation of these projects will be tracked as a measure of demonstrated progress on meeting the plan’s goals.

5.3.1 Progress on Previous Mitigation Actions
A review of 2014 mitigation actions progress reports indicates that Merced County and the participating jurisdictions have been successful in implementing actions identified in the 2014 LHMP Mitigation Strategy, thus, working diligently towards meeting the 2014 plan goals. The 2014 mitigation strategy contained 36 separate mitigation actions. As of September 2021, two of these actions have been completed, three deleted and 39 actions are continuing. The table below summarizes progress implementing mitigation actions by jurisdiction. The total continuing actions column summarizes the actions from 2014 that are either still in progress, have annual implementation, or are continuing but not completed. The new actions in 2021 summarizes the number of actions that were identified during the 2021 plan update process.

Table 5-1 Mitigation Action Progress Summary by Jurisdiction Jurisdiction Completed Deleted Continue
In Progress
Continue
Not
Started
Total
Continuing
Actions
New
Actions
in 2021
Grand
Total
Actions
Atwater 0 2 2 4 6 4 10
Dos Palos NA NA NA NA NA 2 2
Gustine NA NA NA NA NA 4 4
Livingston 0 0 2 6 8 1 9
Los Banos 0 1 7 0 7 8 15
Merced 0 0 2 8 10 1 11
Unincorporated 2 0 7 1 8 12 20
Grand Total 2 3 20 19 39 31 70

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Table 5-2 indicates the details for each of the 2014 mitigation action items that have been completed or deleted.

Table 5-2 Completed and Deleted Mitigation Actions
ID
Corresponding
Hazard(s) Mitigation Action Lead Agency
Goals Priority Action Status Notes
Merced County
10 Drought Promote Water Conservation
Program
OES / CEO's
Office 1,2,3 High
Completed. This
program is in place and
implemented regularly
due to continuing
challenges with
drought.
11 Wildfire Implement and Monitor Weed
Abatement Program County Fire 1,2,3 High Completed.

City of Atwater
7 Flood
Flood Insurance Promotion, CRS
Program
Implementation/Participation
Planning
Department 1,2,3 High
Deleted. The City does
not have enough flood
insurance policies to
justify joining CRS.
9 Drought Promote Water Conservation
Program
Public
Works 1,2,3 High
Deleted. This program is
in place and
implemented regularly
due to continuing
challenges with
drought.

City of Los Banos
7 Flooding
Flood Insurance Promotion, CRS
Program Implementation/
Participation.

Planning
Department 1,2,3 High
Deleted. The City does
not have enough flood
insurance policies to
justify joining CRS.

5.3.2 Updated Action Plan
The results of the project identification and prioritization exercise from meetings 3 and 4 is summarized in Table 5-3. These projects detail specific actions for reducing future hazard-related losses within Merced County. The projects are organized by jurisdictions and include notes about the department and partners necessary to implement the project. Table 5-3 provides more details on the mitigation actions, including the mitigation action description estimated cost, potential funding sources, timeline, indication of the goal(s) that the projects primarily align with and are marked with their relative level of priority high, medium, and low. The following table also provides status/implementation notes that describe progress made on the actions so far, using the following categories, and, where applicable, notes if there were changes in the priority level from the previous plan:
● Continue - In Progress: work has begun on the project and is ongoing. ● Continue - Not completed: little or no work has been done on the project to date and the HMPT agreed to carry over the action into the updated plan.
● New in 2021: The action is new to this plan update; little to no work has been completed.

Many of these mitigation actions are intended to reduce impacts to existing development. Those that protect future development from hazards, as required per the DMA 2000 regulations, are indicated by an asterisk ‘*’ in the action identification number. These actions include those that promote wise

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development and hazard avoidance, such as building code, mapping, and zoning improvements, and continued enforcement of floodplain development regulations.

Table 5-4 provides a summary of the individual mitigation actions by jurisdiction specific to the municipalities that participated in the 2021 plan update. The timeline for implementation for each hazard mitigation action is organized into the following timeframes: ongoing, annual implementation, 1-2 years (short-term), 2-3 years (medium-term), or 3-5 years (long-term). Together with the County actions the tables provide an overview of all the mitigation actions proposed. More details can be found in the respective jurisdictional annexes.

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Table 5-3 Merced County Mitigation Actions
ID
Goal(s)
&
Lifelines
Hazard(s)
Mitigated
Description/Background/
Benefits
Lead
Agency
and
Partners
Cost
Estimate
&
Potential
Funding
Priority Timeline Status/Implementation Notes
1 1,7
NA
MultiHazard:

Dam
Incident,
Earthquake
Flooding
Severe
Weather
Wildfire
Countywide Public Education
Program – A natural hazards
education and awareness program in
Merced County would be a valuable
tool for sharing information with
residents. Implementation ideas
include sharing information online
and conducting workshops. The
county will partner with special
districts, the cities and other entities
to provide awareness and education
on hazards and steps to mitigate.

OES / CEO's
Office
$100,000
Federal
Grants
High Ongoing
Continue In Progress. The 2014
HMP included four of the six
incorporated cities. The 2021
plan included all 6-cities. This
program will expand as a joint
effort between all 6-cities.
2*
1,2,4,6
NA
MultiHazard:

Earthquake,
Flooding,
Severe
Weather,
Wildfire
Integrate Local Hazard Mitigation
Plan into Safety Element of General
Plan. Recognizing the potential
duplication of effort over evaluation
of the same issues, efforts to update
the Health and Safety Element will be
conducted in coordination with the
multi-hazard mitigation plan and to
also ensure AB 2140 Compliance.

Integration and coordination of both
plans provides General Plan policy
direction for development activity.

Potential loss reductions in the
$1000s as any new development
within the county will be considered
Community
Developme
nt Agency
$5,000
General
Fund
Medium
Next
General
Plan
review
cycle
Continue In Progress. The
updated 2021 plan will be
incorporated by reference into
the Safety Element as part of
the MJHMP adoption process.

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ID
Goal(s)
&
Lifelines
Hazard(s)
Mitigated
Description/Background/
Benefits
Lead
Agency
and
Partners
Cost
Estimate
&
Potential
Funding
Priority Timeline Status/Implementation Notes
within the context of the county’s
Health and Safety Element.
3 1,7
NA
Earthquake
Non-structural Earthquake Mitigation
Outreach. Existing structures can be
retrofitted to better withstand
damage from seismic events.

Outreach will include educating home
and business owners about structural
and non-structural retrofit techniques
and how to seismically strengthen
their homes and businesses. Specific
techniques include secure furnishings,
storage cabinets and utilities to
prevent injuries and damages, such as
anchoring, installing lathes, using
flexible connections on gas and water
lines, and bracing propane tanks and
water heaters.

Environmen
tal Health
$100,000
Federal
Grants
Medium Ongoing
Continue In Progress. An
earthquake safety flyer was
created and posted on Public
Health social media and the
Division of Environmental
Health's website.
4 1,2
NA
Earthquake
Countywide Inventory of Historic
Unreinforced Masonry Buildings –
Use GIS a to map and track URMs
Countywide. An accurate inventory of
URM Buildings with appropriate
tracking will lessen time during the
recovery after an EQ.

Building
Department
$100,000
Federal
Grants
Medium 1-2 years
Continue – In Progress. Not
Completed. The County
Building Department has not
tracked or kept records of URM
Buildings in the unincorporated
portion of Merced County.
5 1,2,6
Food,
Water,
Shelter
Earthquake
Periodically review building codes for
updates and enhancements and
ensure necessary capabilities for
enforcement.

Building
Department
Staff time
Dept.

Budget
Medium
Annual
impleme
ntation
Continue – Not Started. The
enforcement of building codes
is standard regulatory practice.

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ID
Goal(s)
&
Lifelines
Hazard(s)
Mitigated
Description/Background/
Benefits
Lead
Agency
and
Partners
Cost
Estimate
&
Potential
Funding
Priority Timeline Status/Implementation Notes
6 1,2,4
Safety
and
Security
Flood
Develop a Hazard Specific Flood
Annex for all jurisdictions with focus
on flood hazard areas as described in
the Risk Assessment. The annex will
address the associated risks of
flooding, current and past mitigation
efforts specific to the streams and
localized flood areas in the county.

OES, Public
Works
$90,000
State and
Federal
Grants
High 1-2 years
Continue In Progress. The
County EOP captures the county
in its entirety. County OES is
working to include all six cities.
7 1,2,7
Safety
and
Security
Flood
Flood Insurance Promotion Program
Implementation/Participation. County
staff will promote benefits of flood
insurance
OES,
Planning
Department
Staff Time
Dept.

Budget
High
Annual
Impleme
ntation
Continue In Progress.
8 1,2,3
Safety
and
Security
Flood
Identify and evaluate effectiveness of
alternative detention basin flood
control projects that will reduce flood
flows in Black Rascal Creek at the
diversion.

Public
Works
$500,000-
4M.

State and
Federal
Grants
High 1-2 years
Continue In Progress. The
County has identified a
preferred alternative as of 2021
but construction has not yet
begun.
9 1,7
NA
Severe
Weather:

Wind,
Extreme
Temps.,
Tornadoes,
Dense Fog
Winter Weather Preparedness
Campaign. This project would add to
and enhance the existing, campaigns
that share information on Severe
Weather Hazards: Fog, Freeze,
Location of Warming Centers, Heat
Related Illness, All Hazards
Preparedness information, etc.; The
county will work with special districts,
the cities and other entities.

OES/CEO’s
Office
$100,000
Federal
Grants
High
Annual
Impleme
ntation
Continue In Progress. This
program is expanded each year
utilizing various outreach
strategies.
10 3
Commun
ications
Cyber
Attack
Cyber Security. Establish a risk
management program to identify the
risks, understand their likelihood and
OES,
Jurisdiction
s
$500,000-
$2,500,000
Grants,
Medium 2-3 years New in 2021

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ID
Goal(s)
&
Lifelines
Hazard(s)
Mitigated
Description/Background/
Benefits
Lead
Agency
and
Partners
Cost
Estimate
&
Potential
Funding
Priority Timeline Status/Implementation Notes
impact. Once identified place security
controls that mitigate the risks to a
level considered acceptable. The risk
management program will also
include ongoing evaluation and
assessment of cyber security risks and
controls throughout the life cycle of
the software. Ideas for
implementation: Define the system.

Identify cyber assets and their
classification. Identify the electronic
security perimeter protecting these
assets. Conduct vulnerability
assessment: Identify threats. Identify
vulnerabilities. Identify security risks
along with their impact and
likelihood. Assess the effectiveness of
existing security controls in mitigating
the risks. Recommend new security
controls or changes to existing
security controls to mitigate the
severity of the risks to a level
acceptable to the organization.

Continuously monitor the
effectiveness of security controls.

Periodically repeat this process to
account for system changes and
changes in the threat landscape.

General
Fund
11 4
NA
Drought Drought Plan. Develop drought plans
that outline proactive strategies that OES
$500,000-
$10,000,00 High 3-5 years New in 2021

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ID
Goal(s)
&
Lifelines
Hazard(s)
Mitigated
Description/Background/
Benefits
Lead
Agency
and
Partners
Cost
Estimate
&
Potential
Funding
Priority Timeline Status/Implementation Notes
can be implemented before, during,
and after drought to increase societal
and environmental resiliency and
enhance drought response and
recovery capabilities Investigate
drought monitoring, risk, and
management options. Include water
conservation projects that seek to
reduce the nonessential use of water
to conserve county water supplies.

Conservation projects include
establishing mandatory water
restrictions within Merced County to
discourage waste and incorporate
treatment of recycled water for
potable consumption.
0 Grants,
General
Fund
12 4
Food,
Water,
Shelter
Drought,
Flood
Groundwater Recharge and
Stormwater Detention Pilot Project. A
pilot project is being conducted by
Eastside Water District on Merced
County property in 2021 that
included installation of three dry wells
at the Mustang Creek Flood
Detention Basin for groundwater
recharge. This project will also assist
in mitigating flooding from
stormwater scenarios. When dry wells
are installed, they will prevent erosion
and localized flooding while also
OES,
County
Water
Resources,
Eastside
Water
District
$500,000-
$3,000,000
Grants,
General
Fund
High 2-3 years New in 2021

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ID
Goal(s)
&
Lifelines
Hazard(s)
Mitigated
Description/Background/
Benefits
Lead
Agency
and
Partners
Cost
Estimate
&
Potential
Funding
Priority Timeline Status/Implementation Notes
allowing collection and control of
stormwater runoff.
13 1,3,6
NA
MultiHazard:

Dam
Incidents,
Earthquake,
HazMat,
Flooding,
Landslide,
Severe
Weather
Wildfire
Public Safety GIS Management. Build
and enhance GIS work done in 2021
Hazard Mitigation Plan Update to
help make the HMP a living
document and an ongoing resource
for understanding risk in Merced
County.

County GIS
Division,
Cities, Cal
OES
$50,000 -
$75,000
Federal,
state and
local
grants,
FEMA
Grants, Cal
OES Funds
High 2-3 years New in 2021
14 NA Wildfire
Encourage and continue to establish
countywide evacuation zones,
sections and routes.

OES
$50,000 -
$75,000
Federal,
state and
local
grants,
FEMA
Grants, Cal
OES Funds
High 2-3 years New in 2021
15 NA
Pandemic/
Epidemic
Conduct an After Action Review for
COVID-19 response to identify
lessons learned and ways to mitigate
impacts of future pandemics.

Public
Health, OES
20,000 -
$40,000
Federal,
state and
local
grants,
FEMA
Medium 1-2 years
New in 2021

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ID
Goal(s)
&
Lifelines
Hazard(s)
Mitigated
Description/Background/
Benefits
Lead
Agency
and
Partners
Cost
Estimate
&
Potential
Funding
Priority Timeline Status/Implementation Notes
Grants, Cal
OES Funds
16 NA
Pandemic/
Epidemic
Develop a plan for a Countywide
Medical Reserve Corps to provide
surge capacity to mitigate impacts of
pandemic/epidemics
Public
Health, OES
Staff Time
Dept.

Budget
Medium 2-3 years
New in 2021
17 NA
Agricultural
Pest &
Disease
Provide public outreach through a
variety of media for awareness and
mitigation of various agricultural
pests and disease.

Agricultural
Commissio
ner, CDFA
Staff Time
Dept.

Budget
Low
2-3 years
New in 2021
18 Food,
Water,
Shelter
Agricultural
Pest &
Disease
Enhance the County’s capabilities
associated with the Pest Detection
Program, Pest Exclusion Program, and
Pest Eradication Program to mitigate
agricultural pests and disease.

Delimitation plan activated through
AG Commissioner and CDFA jointly.

Agricultural
Commissio
ner, CDFA
Staff Time
Dept.

Budget
Low
2-3 years
New in 2021
19 HazMat
Hazardous
Materials
Identify and increase water
management practices that reduce
pesticide movement offsite to
mitigate hazardous materials impacts
Environmen
tal Health
Staff Time
Dept.

Budget
Low
2-3 years
New in 2021
20 NA
Hazardous
Materials
Create a hazardous materials safety
flyer to post on public health social
media and the division of
environmental health's website.

Provide free classes to Merced
County businesses about proper
storage/handling of hazardous
materials and hazardous waste.

Environmen
tal Health
Staff Time
Dept.

Budget
Low
1-2 years
New in 2021

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ID
Goal(s)
&
Lifelines
Hazard(s)
Mitigated
Description/Background/
Benefits
Lead
Agency
and
Partners
Cost
Estimate
&
Potential
Funding
Priority Timeline Status/Implementation Notes
21 HazMat
Hazardous
Materials
Develop countywide commodity flow
study to further understand the
quantity and types of hazardous
materials being transported through
the county to provide the basis for
additional mitigation actions.

Environmen
tal Health
$50,000 -
$175,000
Federal,
state and
local
grants,
FEMA
Grants, Cal
OES Funds
High 2-3 years
New in 2021

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Table 5-4 Jurisdictional Mitigation Action Summary
ID Hazard(s)
Mitigated Project Title Lead Agency and Partners Priority Action Status City of Atwater
1 MultiHazard:

Earthquake
Flooding
Severe
Weather
Wildfire
Participate in
Countywide Public
Education
Program.

OES High Continue Not Started
2*
MultiHazard:

Earthquake
Flooding
Severe
Weather
Wildfire
Integrate Local
Hazard Mitigation
Plan into Safety
Element of
General Plan.

Community
Development
Agency
Medium Continue In Progress
3 Earthquake
Non-structural
Earthquake
Mitigation
Outreach
Public Works Medium Continue Not Started
4 Earthquake
Participate in
Countywide
Inventory for
Unreinforced
Masonry Buildings
-
Public Works Medium Continue Not Started
5*
MultiHazard:

Earthquake
Flooding
Landslide
Severe
Weather
Wildfire
Periodically review
building codes for
updates and
enhancements
Building
Department Medium Continue Not Started
6 Drought
Promote Water
Conservation
Program
Public Works High Continue In Progress
7 Earthquake
Severe
Weather:

General
Dam
Incidents
Emergency power
system to protect
the City of
Atwater 911
Communications
Center and Police
Department
Police
Department High New in 2021
8 Earthquake
Seismic Upgrade
and Remodel of
the Atwater Police
Department
Headquarters
Police
Department High New in 2021

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ID Hazard(s)
Mitigated Project Title Lead Agency and Partners Priority Action Status 9 Earthquake
Review hazards
and awareness of
earthquakes in a
public platform
and educate the
public on helpful
procedures in the
aftermath
Police
Department High New in 2021
10 Agricultural
Pest &
Disease
Public education
of current
seasonal threat
Community
Development
Agency
Low New in 2021
City of Dos Palos
1 MultiHazardRadio upgrade for
police department
Police
Department Medium New in 2021
2 Drought
Construction of
new water
treatment plant
with resiliency
upgrades
Dept. of
Utilities High New in 2021
City of Gustine
1 Flooding
Develop and
enhance storm
water drainage
improvements to
reduce frequent
flooding.

Public Works High New in 2021
2 Earthquake
Perform buildingspecific seismic
vulnerability
assessment of
City-owned
critical facilities
constructed prior
to 1980
Public Works Medium New in 2021
3 Drought Develop drought
plan Public Works High New in 2021
4* Flooding
Explore
cost/benefit of
joining the NFIP
Public Works,
Development
Services
Low New in 2021
City of Livingston
1 MultiHazard:

Dam
Incident,
Earthquake
Flooding
Severe
Weather
Wildfire
Participation in
Countywide Public
Education
Program.

OES High Continue Not Started

Merced County Multi-Jurisdictional Hazard Mitigation Plan Mitigation Strategy
2021-2026 Update Page 5-20
ID Hazard(s)
Mitigated Project Title Lead Agency and Partners Priority Action Status 2 MultiHazard:

Earthquake
Flooding
Severe
Weather
Wildfire
Integrate Local
Hazard Mitigation
Plan into Safety
Element of
General Plan.

Community
Development
Agency
Medium Continue Not Started
3 Earthquake
Non-structural
Earthquake
Mitigation
Outreach
Public Works Medium Continue Not Started
4 Earthquake
Participate in
Countywide
Inventory for
Unreinforced
Masonry Buildings
-
Public Works Medium Continue Not Started
5 MultiHazard:

Earthquake
Flooding
Landslide
Severe
Weather
Wildfire
Periodically review
buildings for
update and
enhancements
Building
Department Medium Continue Not Started
6 Flooding Flood Insurance
Promotion
Planning
Department High Continue Not Started
7 Severe
Weather
Severe Weather
Preparedness
Campaign
Livingston
Fire
Department
High Continue – in progress
8 Drought
Promote Water
Conservation
Program
Public Works High Continue In Progress
9 Flood Upgrade storm lift
station/SCADA Public Works High New in 2021
City of Los Banos
1 MultiHazard:

Earthquake
Flooding
Severe
Weather
Wildfire
Participate in
Countywide Public
Education
Program.

OES / CEO's
Office High Continue – In Progress
2 MultiHazard:

Earthquake
Flooding
Severe
Weather
Wildfire
Integrate Local
Hazard Mitigation
Plan into Safety
Element of
General Plan.

Community
Development
Agency
Medium Continue – In Progress

Merced County Multi-Jurisdictional Hazard Mitigation Plan Mitigation Strategy
2021-2026 Update Page 5-21
ID Hazard(s)
Mitigated Project Title Lead Agency and Partners Priority Action Status 3 Earthquake
Non-structural
Earthquake
Mitigation
Outreach
Public Works Medium Continue – In Progress
4 Earthquake
Participate in
Countywide
Inventory for
Unreinforced
Masonry Buildings
Public Works Medium Continue – In Progress
5 MultiHazard:

Earthquake
Flooding
Severe
Weather
Wildfire
Periodically review
building codes for
updates and
enhancements
and ensure
necessary
capabilities for
enforcement.

Building
Department Medium Continue – In Progress
6 Severe
Weather
Participate in
Severe Weather
Preparedness
Campaign.

Los Banos
Fire
Department
High Continue – In Progress
7 Drought
Promote Water
Conservation
Program
Public Works High Continue – In Progress
8 Wildfire
Implement and
Monitor Weed
Abatement
Program
Los Banos
Fire
Department
High New in 2021
9 Flooding,
Earthquake,
Wildfire
Prepare
Emergency Plan
for Critical
Infrastructure
Public Works High New in 2021
10 Earthquake
Perform BuildingSpecific Seismic
Vulnerability
Assessment of
City-Owned
Critical Facilities
Building
Department High New in 2021
11 Flood
Continue to
Update Storm
Water System
Master Plan
Public Works Medium New in 2021
12 Flood,
Earthquake,
Wildfire
Prepare a Shelter
and Emergency
Provision Plan
Fire
Department Medium New in 2021
13 Severe
Weather
Prepare Weather
Preparedness
Program (Extreme
Heat and Cold)
Fire
Department Medium New in 2021
14 Drought Promote Water
Conservation Public Works High New in 2021

Merced County Multi-Jurisdictional Hazard Mitigation Plan Mitigation Strategy
2021-2026 Update Page 5-22
ID Hazard(s)
Mitigated Project Title Lead Agency and Partners Priority Action Status Program with
continued
updates to Urban
Water
Management Plan
15 Earthquake
Flood,
Wildfire
Rental Home
Inspections
Fire
Department/
Community
Economic
Development
High New in 2021
City of Merced
1 Flooding,
Earthquake,
Wildfire
Prepare an Energy
Assurance Plan Public Works High Continue Not Started
2 Flooding
Develop and
enhance storm
water drainage
improvements to
reduce frequent
flooding
Development
Services High Continue In Progress
3 Dam
Incidents,
Flooding,
Earthquake,
Wildfire
Create a Disaster
Preparedness
Program
Fire
Department High Continue Not Started
4 Flooding
Support Merced
County efforts to
construct the
Haystack
Alternative of
Black Rascal Creek
Development
Services Medium Continue Not Started
5 Flooding
Update the City’s
Storm water
Drainage Master
Plan
Development
Services Medium Continue In Progress
6 Dam
Incidents,
Flooding,
Earthquake,
Wildfire
Prepare a Shelter
and Emergency
Provision Plan
Fire
Department Medium Continue Not Started
7 Wildfire
Prepare a Natural
Area Fire
Prevention Plan
Fire
Department Low Continue Not Started
8 Earthquake
Perform buildingspecific, structural
seismic
vulnerability
assessment of
City-owned
critical facilities
Public Works Low Continue Not Started

Merced County Multi-Jurisdictional Hazard Mitigation Plan Mitigation Strategy
2021-2026 Update Page 5-23
ID Hazard(s)
Mitigated Project Title Lead Agency and Partners Priority Action Status 9 Earthquake
Create a program
to retrofit or
upgrade
unreinforced
masonry buildings
in Downtown
Merced, or other
buildings in the
Plan area.

Development
Services Low Continue Not Started
10 Earthquake
and Flood
Update Fire
Station 52 seismic
and flood
resiliency
Fire
Department Low Continue Not Started
11 Extreme
Heat
Identify and open
additional cooling
zones and centers
within the City of
Merced to provide
additional
capacity of
vulnerable
populations
Police
Department Medium New in 2021
12 Wildfire
Enhance the weed
abatement
program to
mitigate wildfire
risk. Use GIS to
identify properties
where mitigation
is needed. Provide
notice to owners,
and force clean
lots and pursue
cost recovery
expenses.

Fire
Department –
Fire
Prevention
High New in 2021

Merced County Multi-Jurisdictional Hazard Mitigation Plan Plan Adoption, Implementation, and Maintenance
2021-2026 Update Page 6-1
6 PLAN ADOPTION, IMPLEMENTATION, AND MAINTENANCE

6.1 Adoption
The purpose of formally adopting this plan is to secure buy-in from Merced County and the participating jurisdictions, raise awareness of the plan, and formalize the plan’s implementation. The adoption of this plan completes Planning Step 9 of the 10-step planning process: Adopt the Plan. The governing board for each participating jurisdiction has adopted this Local Hazard Mitigation Plan by passing a resolution.

Implementation and maintenance of the plan is critical to the overall success of hazard mitigation planning. This is Planning Step 10 of the 10-step planning process. This section provides an overview of the overall strategy for plan implementation and maintenance, and outlines the method and schedule for monitoring, updating, and evaluating the plan. The section also discusses incorporating the plan into existing planning mechanisms and how to address continued public involvement.

6.2 Implementation
Once adopted, the plan faces the truest test of its worth: implementation. While this plan contains many worthwhile actions, the participating jurisdictions will need to decide which action(s) to undertake first.

Two factors will help with making that decision: the priority assigned the actions in the planning process and funding availability. Low or no-cost actions most easily demonstrate progress toward successful plan implementation.

Implementation will be accomplished by adhering to the schedules identified for each action (see Section 5 for county mitigation actions and the annexes for local mitigation actions), and through constant, pervasive, and energetic efforts to network and highlight the multi-objective, win-win benefits of each project to the Merced County community and its stakeholders. These efforts include the routine actions of monitoring agendas, attending meetings, and promoting a safe, sustainable community. The three main components of implementation are:
● Implement the action plan recommendations of this plan; ● Utilize existing rules, regulations, policies and procedures already in existence; and ● Communicate the hazard information collected and analyzed through this planning process so that the community better understands what can happen where, and what they can do themselves to be better prepared. Also, publicize the “success stories” that are achieved through the HMPT’s ongoing efforts.

During implementation of these efforts, it is important to maintain a constant monitoring of funding opportunities that can be leveraged to implement some of the more costly recommended actions. This will include creating and maintaining a bank of ideas on how to meet local match or participation requirements, should grants be pursued. When funding becomes available, the participating jurisdiction’s will be in a position to capitalize on the opportunity. Funding opportunities to be monitored include DMA Requirements §201.6(c)(3):
[The local hazard mitigation plan shall include] documentation that the plan has been formally approved by the governing body of the jurisdiction requesting approval of the plan (e.g., City Council, county commissioner, Tribal Council).

Merced County Multi-Jurisdictional Hazard Mitigation Plan Plan Adoption, Implementation, and Maintenance
2021-2026 Update Page 6-2
special pre- and post-disaster funds, special district budgeted funds, state and federal earmarked funds, and other grant programs, including those that can serve or support multi-objective applications.

6.2.1 Role of the Hazard Mitigation Planning Team in Implementation and Maintenance With adoption of this plan, the participating jurisdictions will be tasked with plan implementation and maintenance. The participating jurisdictions, led by the Merced County OES agree to:
● Act as a forum for hazard mitigation issues;
● Disseminate hazard mitigation ideas and activities to all participants; ● Pursue the implementation of high-priority, low/no-cost recommended actions; ● Keep the concept of mitigation in the forefront of community decision making by identifying plan recommendations when other community goals, plans, and activities overlap, influence, or directly affect increased community vulnerability to disasters;
● Maintain a vigilant monitoring of multi-objective cost-share opportunities to help the community implement the plan’s recommended actions for which no current funding exists; ● Monitor and assist in implementation and update of this plan; ● Report on plan progress and recommended changes to the Merced County Board of Supervisors and the governing boards of the other participating jurisdictions; and ● Inform and solicit input from the public.

The primary duty of the participating jurisdictions is to see the plan successfully carried out and to report to their community governing boards and the public on the status of plan implementation and mitigation opportunities. Other duties include reviewing and promoting mitigation proposals, considering stakeholder concerns about hazard mitigation, passing concerns on to appropriate entities, and posting relevant information on the county website (and others as appropriate).

6.3 Maintenance and Monitoring
Plan maintenance implies an ongoing effort to monitor and evaluate plan implementation and to update the plan as required or as progress, roadblocks, or changing circumstances are recognized. This section describes how public participation will be integrated throughout the plan maintenance and implementation process. It also explains how the mitigation strategies outlined in this plan will be incorporated into existing planning mechanisms and programs, such as comprehensive land use planning processes, CIP project planning and building code enforcement and implementation. The plan’s format allows sections to be reviewed and updated when new data become available, resulting in a plan that will remain current and relevant.

6.3.1 Maintenance Schedule
In order to track progress and update the mitigation strategies identified in the action plan, the HMPT will revisit this plan at the following times or occurrences:
● Annually, to assess if mitigation actions/projects have been completed; ● Following a significant hazard event;
● Following a disaster declaration; or
● Any other time the HMPT sees it is prudent or necessary.

DMA Requirement §201.6(c)(4)(i):
[The plan maintenance process shall include a] section describing the method and schedule of monitoring, evaluating, and updating the mitigation plan within a five-year cycle.

Merced County Multi-Jurisdictional Hazard Mitigation Plan Plan Adoption, Implementation, and Maintenance
2021-2026 Update Page 6-3
Annual Reviews: The HMPT will meet annually to assess progress on plan implementation. Merced County’s OES Department will facilitate these reviews and an associated meeting. The timing of the annual meeting is recommended for the first or second quarter of each year to identify potential mitigation grants, some of which have a submittal period in the fourth quarter. A template for the annual meeting and a summary report is provided in Appendix E. Another tool developed during the 2021 process to facilitate regular review and implementation and make the plan more of a “living document” is the LHMP website that includes a GIS/map based –interactive storyboard with highlights of the risk assessment, including interactive hazard maps and a web-based method for collecting, validating, updating and maintaining critical facilities for the plan. This website is accessible from the Merced County OES homepage.

Critical Facility Database Maintenance: Moving forward the County and its municipalities will maintain the critical facility database that was prepared during the 2021 update. The County’s GIS Manager will lead periodic reviews of the database and assess the need for updates, leveraging the LHMP website and Arc-GIS Experience Builder Application noted above.

Five-Year Update: This plan will be updated, approved, and adopted within a five-year cycle as per Requirement §201.6(c)(4)(i) of the Disaster Mitigation Act of 2000. Efforts to begin the update should begin no later than June 2025. The County will monitor planning grant opportunities from the CalOES and FEMA for funds to assist with the update. This may include submitting a Pre-Disaster Mitigation planning grant application. This grant should be submitted in 2024, as there is a three-year performance period to expend the funds, and there is no guarantee that the grant will be awarded when initially submitted. This allows time to resubmit the grant in subsequent years, if needed. Updates to this plan will follow the most current FEMA and CalOES planning guidance. The next plan update should be completed and reapproved by CalOES and FEMA Region VIII by September 2026.

6.3.2 Maintenance and Evaluation Process
The HMPT will continually observe the incorporation process, evaluation method, updating method, continued public participation, and completion of the action/projects to assure that the HMPT and the plan itself are performing as anticipated. By monitoring these processes, the HMPT will then be able to evaluate them at the time of the plan update, determining if any changes are needed.

The MJHMP plan update every five years provides an opportunity to determine whether there have been any significant changes in the county that may, in turn, necessitate changes in the types of mitigation actions proposed. New development in identified hazard areas, an increased exposure to hazards, the increase or decrease in capability to address hazards, and changes to federal or state legislation are examples of factors that may affect the necessary content of the MJHMP.

The plan review provides county officials with an opportunity to evaluate those actions that have been successful and to explore the possibility of documenting potential losses that were avoided due to the implementation of specific mitigation measures. The plan review also provides the opportunity to address mitigation actions that may not have been successfully implemented as assigned.

During the five-year plan update process, the following questions will be considered as criteria for assessing the effectiveness and appropriateness of the Plan:
● Do the goals address current and expected conditions? ● Are the goals and objectives consistent with changes in State and Federal policy? ● Complete status update on all mitigation projects. What strategies should be revised? ● Has the nature or magnitude of risks changed (current and expected conditions)? ● Are the current resources appropriate for implementing the LHMP?

Merced County Multi-Jurisdictional Hazard Mitigation Plan Plan Adoption, Implementation, and Maintenance
2021-2026 Update Page 6-4
● Are there implementation problems, such as technical, political, legal or coordination issues with other agencies?
● Have the outcomes occurred as expected?
● Did the county and participating agencies and other partners participate in the plan implementation process as assigned?
The County of Merced is committed to involving the public in the continual reshaping and updating of the MJHMP, as discussed in subsection 6.3.4.

6.3.3 Incorporation into Existing Planning Mechanisms
Another important implementation mechanism that is highly effective and low-cost is incorporation of the hazard mitigation plan recommendations and their underlying principles into other county and city plans and mechanisms. Where possible, plan participants will use existing plans and/or programs to implement hazard mitigation actions. This plan should also be cross-referenced when related planning mechanisms are updated. As previously stated above, mitigation is most successful when it is incorporated into the day-to-day functions and priorities of government and development. As described in this plan’s capability assessment and jurisdictional annexes, the County and participating jurisdictions already implement policies and programs to reduce losses to life and property from hazards. This plan builds upon the momentum developed through previous and related planning efforts and mitigation programs and recommends implementing actions, where possible, through these other program mechanisms.

These existing mechanisms include (but are not limited to) the following:
● County and local general plans (2030 General Plan)
● Community service district area plans and master plans ● County and local emergency operations plans
● County and local ordinances
● Flood/stormwater management/master plans
● Community wildfire protection plans
● GSPs
● IRWMPs
● Stormwater Resource Plans
● Urban Water Management Plans (UWMPs)
● CIPs
● Other plans and policies outlined in the capability assessments in the jurisdictional annexes ● Other plans, regulations, and practices with a mitigation focus HMPT members involved in the updates to the planning mechanisms will be responsible for integrating the findings and recommendations of this plan with these other plans, programs, etc., as appropriate. As an action step to ensure integration with other planning mechanisms the County Office of Emergency Services Manager or designee will discuss this topic at the annual meeting of the HMPT described above in subsection 6.3.1. The HMPT will discuss where there are opportunities to incorporate the plan into other planning mechanisms and who would be responsible for leveraging those opportunities. HMPT members representing local jurisdictions will work with their jurisdictional planning teams to integrate their identified mitigation actions into their own local plans and programs. Efforts to integrate the hazard mitigation plan into local plans, programs, and policies will be reported on at the annual HMPT plan review meeting, and a record of successful integration efforts will be kept.

Efforts should continuously be made to monitor the progress of mitigation actions implemented through these other planning mechanisms and, where appropriate, their priority actions should be incorporated into updates of this hazard mitigation plan.

Merced County Multi-Jurisdictional Hazard Mitigation Plan Plan Adoption, Implementation, and Maintenance
2021-2026 Update Page 6-5
Examples of a process for incorporation of the MJHMP into specific existing or upcoming planning mechanisms include:
● Each community (County, Atwater, City of Merced, Dos Palos, Gustine, Livingston, Los Banos) should adopt (by reference or incorporation) this MJHMP into the Safety Element of their General Plan(s), as encouraged by AB 2140. Evidence of such adoption (by formal, certified resolution) shall be provided to Cal OES and FEMA to become eligible or maintain eligibility for CDDA funding. Each jurisdiction has a specific mitigation action related to this process outlined in subsection 5.3. ● Reference into the State of California CVFPP.
● Incorporation into the City of Merced Emergency Operations Plan and Fire Department Strategic Plan. ● Incorporation into the City of Los Banos Emergency Operations Plan and Fire Department Strategic Plan.
● Referencing the HMP in the University of California Merced’s Biosafety Manual and Emergency Operations Plan.

6.3.4 Continued Public Involvement
Continued public involvement is imperative to the overall success of the plan’s implementation. Efforts will be made to involve the public in the plan maintenance, evaluation, and review process. This includes maintaining a digital version of the plan on the County OES website for public review. In addition, information on who to contact within the OES will be posted with the plan. The Merced County OES will maintain a file of comments received for reference during the next five-year update. Any revisions to the plan that may occur as a result of a disaster will also be made public and posted on the county website.

The next five-year update process also provides an opportunity to solicit participation from new and existing stakeholders and to publicize success stories from the plan implementation and seek additional public comment. A public hearing(s) or survey to receive public comment on the plan will be held during the plan update period. When the HMPT reconvenes for the update, they will coordinate with all stakeholders participating in the planning process, including those who joined the HMPT after the initial effort, to update and revise the plan. Public notice will be posted, and public participation will be invited, at a minimum, through available website postings and press releases to the local media outlets as well as email and social media announcements.

Public involvement strategies that were used during the 2021 planning process are captured in the Outreach Strategy in Appendix F. The appendix can serve as a reference for continued public involvement over the next several years and lays the foundation for outreach associated with the next formal five-year update.

Merced County Multi-Jurisdictional Hazard Mitigation Plan Plan Adoption
2021-2026 Update Page 7-1
7 PLAN ADOPTION

7.1 Element E.1 Formal Adoption Documentation
Adoption by the local governing body demonstrates the community’s commitment to implementing the mitigation strategy and authorizes responsible agencies to execute their actions. The final plan is not approved until Merced County and each participating jurisdiction adopts the plan and FEMA receives documentation of formal adoption by the governing body of each jurisdiction requesting approval. This plan is for Merced County, the unincorporated county, and its incorporated cities of Atwater, Livingston, Dos Palos, Gustine, Merced, and Los Banos.

Merced County and the six participating cities plan to submit this plan to the Merced County Board of Supervisors and their respective city councils upon successful completion of State and federal review and following the issuance of an Approved Pending Adoption (APA) designation from FEMA. This provides an efficient approval process if FEMA determines the MJHMP requires revisions because the County and each participating city can make these revisions prior to initiating the local plan adoption process.

Once FEMA issues APA notification, adoption by each participating jurisdiction must take place within one year for each jurisdiction to become or remain eligible for FEMA HMA program funding. Given this is a multi-jurisdictional planning process, Merced County will coordinate the adoptions of all six jurisdictions as soon as the plan receives APA status. Because each City’s governing bodies have different meeting schedules, Merced County will also coordinate with each participating jurisdiction regarding the timing of their adoptions to submit adoption documentation to Cal OES and FEMA at the same time.

Once the County records and submits the adoption documentation to Cal OES and FEMA, FEMA will issue an official approval letter stating which jurisdictions have adopted and are approved and eligible for FEMA HMA program funding. The approval letter will include the expiration date five years from the date of the letter and attached to the approval letter will be a final FEMA Local Mitigation Plan Review Tool that provides feedback on the strengths of the plan, recommendations for plan improvements during future plan updates, and suggestions for implementing the mitigation strategy.

DMA Requirement §201.6(c)(5):
[The plan shall include...] Documentation that the plan has been formally adopted by the governing body of the jurisdiction requesting approval of the plan (e.g., City Council, County commissioner, Tribal Council).

Merced County Multi-Jurisdictional Hazard Mitigation Plan References
2021-2026 Update Page 8-1
8 REFERENCES
Arcuni, Peter, Rivers in the Sky: What You Need to Know About Atmospheric River Storms. KQED, Jan. 2019
California Accidental Release Prevention Program.California Climate Action Team (CAT) Heat Adaptation Workgroup, “Preparing California for Extreme Heat,” October 2013 California Climate Adaptation Strategy 2018
California Department of Finance, 2015-2019 American Community Survey (ACS), 5-year estimates, U.S.

Census Bureau
California Department of Forestry and Fire Protection website California Department of Water Resources, 2006, “Drought Preparedness.” California Department of Water Resources, Division of Safety of Dams, Jurisdictional Dams Database California Department of Water Resources, Water Conditions and Drought Report to Governor, 2009 California Department of Water Resources. www.water.ca.gov/.

California Emergency Management Agency, Disaster Recovery and Mitigation Handbook California Emergency Management Agency, Tools for Preparing your LHMP, 2012 California Environmental Protection Agency, Department of Toxic Substance Control California Fire Plan, 2010
California Governor’s Office of Emergency Services. Contingency Plan for Excessive Heat Emergencies. 2014.

California Governor’s Office of Emergency Services. FY 2019-2020 Public Safety Power Shutoff Legislative Report.

California Governor’s Office of Planning and Research. The Integrated Climate Adaption and Resiliency Program. Impact Report and 2020 Program Recommendations.

California Invasive Plant Council. https://www.cal-ipc.org/ California Megaflood: Lessons from a Forgotten Catastrophe. B. Lynn Ingram. Scientific American, January 1, 2013. https://www.scientificamerican.com/article/atmospheric-rivers-california-megaflood-lessonsfrom-forgotten-catastrophe/ California Natural Resources Agency (CNRA), Fourth Climate Change Assessment Report, 2018 California Public Utilities Commission
Center for Disease Control, Agency for Toxic Substances and Disease Registry, Social Vulnerability Index Center for Western Weather and Water Extremes, Atmospheric Rivers scale. http://cw3e.ucsd.edu/CW3EReleases-New-Scale-to-Characterize-Strength-and-Impacts-of-Atmospheric-Rivers/ City of Atwater Emergency Plan, 2017.

City of Atwater Fire Department. City Fire Management Plan.

Merced County Multi-Jurisdictional Hazard Mitigation Plan References
2021-2026 Update Page 8-2
City of Atwater General Plan. 2000
City of Dos Palos General Plan. 1991.

City of Dos Palos Local Emergency Operations Plan. 2003.

City of Gustine General Plan. 2002.

City of Livingston General Plan. 2020-2025.

City of Los Banos Emergency Plan. 2011.

City of Los Banos Fire Management Plan.

City of Los Banos General Plan. 2009
City of Merced 2030 General Plan. 2012.

City of Merced Emergency Response/Disaster Plan. 2011.

City of Merced Hazard Mitigation Plan 2015.

City of Merced Tentative Subdivision Activity List. May 2021. Prepared by the City of Merced Development Services Department. Accessed on December 10, 2021. Available at:
https://www.cityofmerced.org/home/showpublisheddocument/15200/637661978774630000 Department of Finance Data, Merced County 2012
Environmental Protection Agency, National Response Center Federal Emergency Management Agency, Local Mitigation Plan Review Guide, 2011 FEMA Community Information System
FEMA, CRS Coordinators Manual
Federal Emergency Management Agency, Local Mitigation Plan Review Guide, 2011 Flood Emergency Information Exchange
Flood Insurance Study, Merced County – FEMA, December 2, 2008 Flood Insurance Study, Merced County – FEMA, 2010
Gao Y, J Lu, LR Leung, Q Yang, S Hagos and Y Qian, 2015. "Dynamical and Thermodynamical Modulations on Future Changes of Landfalling Atmospheric Rivers over Western North America." Geophysical Research Letters 42(17): 7179-7186. DOI: 10.1002/2015GL065435 Atmospheric Sciences and Global Change Research Highlights. October 2015 https://www.pnnl.gov/science/highlights/highlight.asp?id=4106 Gray, E., Gilardoni, S., Baldocchi, D., McDonald, B. C., Facchini, M. C., & Goldstein, A. H. (2019). Impact of air pollution controls on radiation fog frequency in the Central Valley of California. Journal of Geophysical Research: Atmospheres, 124, 5889–5905. https://doi.org/10.1029/2018JD029419 Madera-Mariposa-Merced Unit Pre-Fire Management Plan, 2005 Merced County 2035 General Plan (2010, Amended 2016)
Merced County 2035 General Plan, Health and Safety Element (2012) Merced County Agricultural Commissioner’s Report, 2019
Merced County Association of Government. Population Projections.

Merced County Emergency Operations Plan (2008)