City Council / Housing Authority
May 18, 2026

Charts Source: LA County Public Works; 2021 County Comprehensive Flood Plan average replacement cost of structures in the floodplain—indicating significant gaps in financial resilience.
• Wildfire burn scars and post-fire hydrophobic soils significantly increase flood and debris flow risks, particularly in foothill and canyon communities. This hazard continues to grow in severity with climate-driven fire seasons.

6.6.8 Mitigation and Preparedness
Los Angeles County’s flood mitigation strategy reduces hazard exposure, enhances community resilience, and supports long-term climate adaptation. Grounded in FEMA’s National Mitigation Framework, CalOES planning guidance, and local policy, the County implements both structural and non-structural measures to address current and future flood risks. Core actions include regular maintenance and targeted upgrades to Estimated Damage to Critical Facilities in Unincorporated Areas from 100-Year Flood Sector Number of Facilities
Affected
Average % of Total Value
Damaged
Structure Content
Safety & Security 1 7.56 10.24
Food, Water & Sheltering 9 6.72 18.73
Health & Medical 0 N/A N/A
Energy 1 23.90 47.79
Communications 0 N/A N/A
Transportation 59 1.41 8.86
Hazardous Materials 0 N/A N/A
Total/Average 70 9.90 21.40
Estimated Damage to Critical Facilities in Unincorporated Areas from 500-Year Flood Sector Number of Facilities Affected
Average % of Total Value
Damaged
Structure Content
Safety & Security 4 28.39 37.56
Food, Water & Sheltering 41 7.73 27.01
Health & Medical 0 N/A N/A
Energy 1 23.90 47.79
Communications 2 5.00 16.00
Transportation 107 3.38 19.74
Hazardous Materials 30 10.00 15.00
Total/Average 185 13.07 27.18
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stormwater infrastructure, restoration of floodplains, and integration of flood hazard data into land use planning. The County also prioritizes the protection of critical facilities and vulnerable housing through site retrofits, property acquisition, and elevation programs. Public outreach is conducted through a bilingual, ADA-accessible Program for Public Information, which promotes flood safety awareness, emergency preparedness, and participation in the National Flood Insurance Program (NFIP).

To ensure that mitigation is both data -driven and community -centered, the County utilizes climate projections and FEMA’s HAZUS modeling to inform investments, while coordinating with regional partners to align local actions with broader watershed strategies. Key components of the approach include:
• Upgrading culverts, debris basins, and drainage systems to manage increased runoff
• Promoting low-impact development (LID) and incorporating green infrastructure in urban design
• Updating ordinances and the General Plan to discourage development in high-risk areas
• Maintaining inventories of repetitive loss areas and prioritizing resources for the most vulnerable populations
This comprehensive strategy ensures Los Angeles County not only meets federal and state standards but advances flood risk reduction in a way that safeguards people, property, and natural systems for the future.

6.6.9 Summary
Flooding is one of the most persistent and complex natural hazards in Los Angeles County, intensified by climate change, urbanization, and aging infrastructure. The Los Angeles County region experiences a range of flood types, including stormwater runoff, flash flooding, coastal inundation, and post -wildfire debris flows. These events are most common during winter storms and atmospheric river systems. High -density development, extensive paved surfaces, and fire-damaged hillsides contribute to rapid runoff and increased overall flood vulnerability. Areas along (but not limited to) the Los Angeles, San Gabriel, and Santa Clara Rivers, as well as coastal communities and foothill regions, are particularly at risk.

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Los Angeles County’s mitigation strategy is proactive and multifaceted. It includes infrastructure upgrades, nature-based solutions, land use policy updates, and public education. Core priorities focus on protecting critical facilities, reducing exposure in high-risk housing, and promoting community resilience. Planning efforts are supported by FEMA’s HAZUS risk modeling and local climate projections. Despite progress, more than 750,000 residents remain at risk from major flood events, reinforcing the need for continued investment in comprehensive, flood risk reduction across the county.

6.6.10 National Flood I nsurance Program (NFIP) Repetitive Loss (RL)
According to the Los Angeles County Public Works, there are 55 Repetitive Loss (RL) properties in 28 RL areas of Unincorporated Los Angeles County as of 2025 , and 8 Severe Repetitive Loss Properties (SRLP). A Repetitive Loss (RL) property is any insurable building for which two or more claims of more than $1,000 were paid by the National Flood Insurance Program (NFIP) in any rolling 10 -year period since 1978. Updated location information about RL properties in Unincorporated Los Angeles County were not available during the drafting of this plan, but is being finalized and will be included in subsequent hazard mitigation efforts. Data from 2011 showed that 24 RL properties were located in the SFHA. At the time, the Los Angeles County Public Works stated, “the majority of the repetitive losses are associated with localized urban drainage flood problems, even for properties within a FEMA-designated flood zone.” The Los Angeles County Public Works oversees RL mitigation projects.

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6.7 Dam Failure

6.7.1 Nature
Dam failure refers to the structural collapse of a
dam that results in the sudden and uncontrolled
release of stored water. Such failures can occur
due to age- related deterioration, inadequate
spillway capacity, structural damage from
seismic activity or flooding, and poor
maintenance. The catastrophic release of water
from a dam failure has the potential to cause
human casualties, significant economic loss, and
environmental destruction. This type of disaster
is particularly dangerous because it can occur
suddenly, leaving little time for evacuation or
emergency response efforts.

The magnitude of flooding from dam failure
often exceeds the capacity of downstream
channels, causing rapid inundation of
surrounding areas. This flooding can lead to
extensive property damage, erosion,
infrastructure destruction, and contamination of
water supplies. Additionally, secondary hazards
such as landslides and debris flows can be
triggered, compounding the disaster’s impact.

The structural stress on dams may rise as dams
age, and climate variability increases the frequency of extreme precipitatio n events.

Planning efforts include both dams and debris basins. To simplify language of the plan both reservoir dams and storm water debris basins will be referred to as dams.

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6.7.2 Location
Los Angeles County has over 90 dams regulated by the California Department of Water Resources’ Division of Safety of Dams (DSOD). Fifteen (15) of these dams and eighteen (18) debris basins are owned and operated by the Los Angeles County Public Works (PW). In 2017, the California Legislature mandated that all state -jurisdictional dams (excluding those classified as Low Hazard) develop dam breach inundation maps and Emergency Action Plans (EAPs) approved by DSOD and Cal OES.

Many of these dams are located near highly populated areas, increasing the potential for human and economic impacts during a failure event. Seventy (70) dams are classified as High or Extremely High hazard potential dams, meaning their failure could result in significant loss of life and widespread property damage.

The Whittier Narrows Dam, reclassified as the U.S. Army Corps of Engineers’ (USACE) highest-priority dam safety concern, poses one of the greatest risks due to its potential to flood highly populated areas from Pico Rivera to Long Beach. USACE has determined that an extreme storm event has a 1 in 900 (0.1%) chance of causing catastrophic failure annually. Mitigation actions related to County -owned dams are prioritized based on their hazard level and potential to impact populated areas.

For a better visual representation of this Dam Failure Hazard within the LA County planning area, please reference Appendix A for all the County owned dams and debris basins maps.

6.7.3 Extent
The Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures (FEMA P -946, 2013) categorizes dam hazards into four classifications:
• Low Hazard: Minimal damage expected, no loss of life. • Significant Hazard: Potential for property damage and economic disruption. • High Hazard : Likely to result in loss of life and significant damage to critical infrastructure.
• Extremely High Hazard (DSOD Classification): Could cause large-scale fatalities and inundate areas with over 1,000 residents.

Given the population density of Los Angeles County, a dam failure classified as High or Extremely High Hazard would likely cause substantial human casualties, displace entire communities, and inflict severe economic and environmental damage. Table 6-3 and 6-4 below shows a list of dams and debris basins owned by PW along with their hazard classifications. Potential mitigation actions described in this AHMP are only applicable to the dams and debris basins owned by PW and implementation of these actions are the responsibility of the PW Stormwater Engineering Division – Dams Section.

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Table 6-3: Los Angeles County PW Dam Hazard Status
Dam Name Hazard Status Location
Big Dalton Extremely High Glendora, CA
Big Santa Anita Extremely High Monrovia, CA
Big Tujunga No. 1 Extremely High Tujunga, CA
Cogswell Extremely High Azusa, CA
Devils Gate Extremely High LA Canada Flintridge, CA
Live Oak Extremely High La Verne, CA
Morris Extremely High Azusa, CA
Pacoima Extremely High Pacoima, CA
Puddingstone Extremely High San Dimas, CA
Puddingstone Diversion High La Verne, CA
San Dimas Extremely High La Verne, CA
San Gabriel No. 1 Extremely High Azusa, CA
Sawpit Extremely High Monrovia, CA
Sierra Madre High Sierra Madre, CA
Thompson Creek Extremely High Claremont, CA

Table 6-4: Los Angeles County PW Debris Basin Hazard Status Debris Basin Name Hazard Status Location
Bailey Debris Basin High Sierra Madre, CA
Big Dalton Debris Basin High Glendora, CA
Blanchard Debris Basin High Tujunga, CA
Brand Debris Basin High Glendale, CA
Eaton Wash Debris Basin Extremely High Pasadena, CA
La Tuna Debris Basin Extremely High Sun Valley, CA
Laguna Regulating Basin Significant Alhambra, CA
Little Dalton Debris Basin Extremely High Glendora, CA
Lower Sunset Debris Basin High Burbank, CA
Morgan Debris Basin High Glendora, CA
Rubio Debris Basin High Altadena, CA
Santa Anita Debris Basin Low Arcadia, CA
Sawpit Debris Basin Extremely High Monrovia, CA
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Debris Basin Name Hazard Status Location
Schoolhouse Debris Basin High Los Angeles, CA
Sierra Madre Villa Extremely High Sierra Madre, CA
Stevenson Ranch High Stevenson Ranch, CA
Stough Debris Basin Extremely High Burbank, CA
Wilson Debris Basin High Los Angeles, CA

6.7.4 History
Los Angeles County has experienced one of the deadliest dam failures in U.S. history:
• St. Francis Dam Failure (March 12-13, 1928):
o Released 12.4 billion gallons of water
o At least 411 fatalities
o Devastated towns from San Francisquito Canyon to Ventura County o Resulted in sweeping changes to California dam safety regulations and the creation of state oversight for civil engineers
While no major dam failures have occurred in recent decades, concerns over aging dam infrastructure, seismic risks, and increasing climate variability have raised alarms about future risks. Studies indicate that many California dams, including those in Los Angeles County, require structural updates to withstand modern hydrological conditions and potential seismic activity. There have been no federal declarations or state proclamations for dam failure in the last five years.

6.7.5 Dam Coordination
Los Angeles County Public Works coordinates with local, state, and federal agencies to mitigate flood risk hazards to downstream communities from its dams. At the local level, PW works with cities and public agencies during development of Emergency Action Plans (EAP). This provides local stakeholders with the opportunity to review the EAP , provide feedback, and confirm responsibilities and roles during an EAP activation. At request from local jurisdictions, PW may provide tours of its dam facilities, where information on dam safety and the potential hazards associated with dam failures are shared.

At the state level, PW works with the DSOD to meet compliance with state dam safety standards and flood management at all of PW’s dams. This includes annual dam County of Los Angeles
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inspections, review, approval, and oversight of dam construction projects, review of dam safety monitoring, and oversight of other dam safety regulatory activities. PW also coordinates with various state agencies, including DSOD, Cal OES, and Caltrans during development of EAPs.

At the federal level, PW works with the Federal Energy Regulatory Commission (FERC) to meet compliance with state dam federal standards and flood management at PW’s San Gabriel Dam, which is under FERC jurisdiction. This includes annual dam inspections, review, approval, and oversight of dam construction projects, review of dam safety monitoring, EAP coordination, and oversight of other dam safety regulatory activities. PW also coordinates with the United States Army Corps of Engineers (USACE) on operations of interconnected dam facilities and emergency response planning for USACE facilities that may be in the pathway of dam failure impacts.

Information Sharing
PW provides critical information to relevant local, state, and federal stakeholders to address hazard mitigation related to dam safety. This includes:
• Emergency Action Plans (EAPs): EAPs outline the roles, responsibilities, and procedures to follow in the event of a dam emergency. The EAPs include i n u n d a t i o n m a p s , w h i c h s h o w a r e a s t h a t w o u l d b e a f f e c t e d b y a d a m f a i l u r e , helping to identify populations at risk. These plans are shared with stakeholders to ensure a coordinated response. Due to the sensitive nature of information contained within the EAPs, they are confidential and not released to the general public.
• Inundation Maps: Inundation maps are critical tools for identifying areas and populations at risk in the event of a dam failure. They also indicate potential impacts on critical infrastructure facilities such as hospitals, schools, and transportation networks. These maps are shared with relevant stakeholders recognized in the EAP and are available to the general public through the DSOD Dam Breach Inundation Map Web Publisher.

6.7.6 Probability
Los Angeles County contains over 90 state-jurisdictional dams, with approximately 70 classified as High or Extremely High Hazard by the California Division of Safety of Dams (DSOD), meaning their failure could result in loss of life and significant propert y damage.

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Although comprehensive failure probabilities are not published for each dam, FEMA and DSOD guidance suggest that the general annual probability of failure for High Hazard dams nationwide ranges from 0.01% to 0.1% (or 1 in 10,000 to 1 in 1,000) depending on maintenance, age, seismic vulnerability, and other site-specific factors.

Applying this range to Los Angeles County:
• The aggregate annual probability of a significant dam failure event in the county—across one or more of the 70 high -risk dams—is estimated at between

0.1% and 0.5% annually, factoring cumulative exposure and different hazard classifications. (Such as earthquake or flood related)
• Climate change, aging infrastructure, and seismic activity in Los Angeles County increase systemic risk across multiple structures simultaneously.

In summary, while the individual likelihood of failure for any one dam is very low, the overall countywide probability of at least one major dam failure event is low but still warrants continued vigilance, maintenance, and emergency planning.

6.7.7 Vulnerability
A catastrophic dam failure in Los Angeles County could have severe consequences for hundreds of thousands of residents. The densely populated nature of the county, combined with the location of several large dams near residential and commercial areas, increases the potential for widespread displacement, loss of life, and economic damage. The 2024 THIRA identifies multiple high -risk zones where dam failure could result in extensive flooding and mass evacuations.
• High-risk dams, among others, pose a significant threat to densely populated communities. A breach in any of these dams could inundate entire neighborhoods, affecting more than 500,000 residents in low -lying areas and floodplains.
• Socially vulnerable populations, including elderly individuals, the AFN community, people experiencing homelessness, low-income communities, and non-English-speaking residents face heightened risks during evacuations and recovery due to limited mobility, financial constraints, and access to resources. • Educational and healthcare institutions are at risk, with several schools, hospitals, and long-term care facilities located in flood -prone areas. A major dam failure could result in school closures, displacement of students, and disruption of healthcare services.

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• Evacuation and emergency sheltering demands would be substantial, requiring the rapid mobilization of resources to support displaced residents. Temporary shelters, emergency medical services, and logistical support would need to be activated to accommodate evacuees.

Los Angeles County relies heavily on dams and reservoirs for water storage, flood control, and supply regulation. Catastrophic dam failure poses an acute threat to life and property, especially in low-lying, highly populated downstream areas.

Extent of Exposure
• Total Area Exposed: 490.64 sq mi
• Supervisorial Districts (SD) Impacted:
o SD5: 223.88 sq mi (7.97%)
o SD1: 162.25 sq mi (45.98%)
o SD2: 66.57 sq mi (18.32%)
o SD3: 25.76 sq mi (5.97%)
o SD4: 12.17 sq mi (5.72%)
• Critical Facilities Affected:
o Fire Department: 112 (33.22%)
o Public Works: 92 (40.00%)
o Health Services: 29 (44.62%)
o Public Health: 17 (42.50%)
o Libraries: 30 (34.48%)
o Parks: 65 (35.50%)
o Education: 34 (41.46%)
Problem Statement
Dam failure, while rare, can have catastrophic consequences in densely populated downstream areas. With significant portions of critical infrastructure exposed — particularly in SD1 and SD5 —planning for emergency evacuations, early warning systems, infrastructure hardening, and downstream development regulation is critical to saving lives and reducing loss.

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A failure or breach of a High Hazard Potential Dam (HHPD) in Los Angeles County would result in catastrophic consequences for downstream communities, with the greatest vulnerabilities concentrated in densely populated urban areas. Rapid and massive floodin g would likely inundate residential neighborhoods, commercial districts, and industrial zones within minutes to hours, depending on proximity and topography. Critical infrastructure—including hospitals, fire and police stations, schools, and major transp ortation corridors —would be severely impacted, disrupting emergency services and evacuation routes. Thousands of people, including vulnerable populations such as those with Access and Functional Needs (AFN), elderly residents, and low -income households, would face immediate life -threatening conditions, displacement, and limited access to medical care or shelter. Economic losses would be compounded by damage to utilities, including power substations and water systems, potentially leaving large swaths of the region without essential services. The sheer scale of devastation from a dam failure, especially at facilities such as Whittier Narrows or Castaic Dam, underscores the critical importance of continued risk reduction, early warning systems, and dam rehabilitation efforts.

6.7.8 Data Limitations
A limitation of this AHMP is that planning efforts only covered PW -owned dams in Los Angeles County. Future mitigation planning should include other dam owners and operators in Los Angeles County such as the US Army Corps of Engineers. The data on high-hazard dams reviewed during the 2025 AHMP planning process was genera lly suitable for the analysis required. Future opportunities for obtaining additional data to be considered in the next update to the plan should:
• Incorporate more current information as it becomes available. • Assess any new or updated EAPs for dams owned by Los Angeles County. • Identify and review more current structural or condition assessment data to inform future risk assessments.
• Involve other dam owners within Los Angeles County in future planning efforts.

6.7.9 Impacts
A dam failure in Los Angeles County would have catastrophic and immediate consequences for life, property, and critical infrastructure, particularly in the densely populated downstream areas. The sudden release of impounded water from a High or Extremely High Hazard dam could inundate neighborhoods within minutes, allowing little to no time for evacuation. More than 500,000 residents live within identified dam inundation zones, many of whom are in socially vulnerable populations —including County of Los Angeles
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individuals with limited mobility, low -income households, and people experiencing homelessness—making rapid evacuation and sheltering especially challenging.

County-owned high hazard potential dams and their locations are listed in Table 6 -3.

Inundation maps for County-owned high hazard potential dams are listed in Appendix A-7.

Critical infrastructure is also at significant risk. Hospitals, fire stations, law enforcement facilities, emergency operations centers, schools, and wastewater treatment plants located in downstream zones may be damaged or rendered inoperable, severely disrupting emergency response and lif e-sustaining services. Major transportation routes such as interstates, rail lines, and arterial roads could be submerged or washed out, impeding rescue and recovery efforts. Additionally, power substations, water distribution networks, and telecommunicati ons infrastructure could suffer cascading failures, contributing to widespread outages and prolonged recovery periods.

The economic consequences of dam failure would be immense. Beyond property damage, business operations in inundated areas would halt, leading to loss of employment, tax revenue, and economic activity. Industrial zones (especially those near major flood control reservoirs or channels) could potentially release hazardous materials if overwhelmed, posing secondary environmental and public health hazards.

Debris accumulation, sedimentation, and contamination could severely impact ecosystems, water quality, and flood control infrastructure downstream, complicating both emergency cleanup and long-term environmental recovery.

Given the scale of potential impacts, dam failure is considered a stable low-probability but high-consequence hazard in Los Angeles County, requiring continued investment in structural mitigation, emergency preparedness, and public awareness to reduce the severity of its effects.

6.7.10 High Hazard Potential Dams Goals
Goal 1: Enhance resilience across dam/debris basin infrastructure, including high - hazard potential dams, and other critical facilities within dam inundation zones.

Goal 2: Encourage structural reinforcement or retrofits for aging and vulnerable dams.

Goal 3: Ensure all dams/ debris basins have updated Emergency Action Plans (where applicable) and updated dam inundation mapping consistent with state standards.

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6.7.11 Mitigation and Preparedness
Los Angeles County and state agencies have implemented various mitigation efforts to reduce the risks associated with dam failures:
• Structural Reinforcements: Upgrading spillways, strengthening earthen dams, and implementing seismic retrofitting measures.
• Emergency Action Plans (EAPs): Mandated by DSOD for all High and Extremely High hazard dams to guide evacuation and response efforts. • Early Warning Systems: Improved flood monitoring and automated alert systems to notify at-risk communities in real-time.

6.7.12 High Hazard Potential Dam Prioritization
The risk assessment within the 2025 AHMP considers the county planning area’s vulnerability and potential impacts related to HHPDs. Mitigation actions and planning efforts that are related to mitigating long-term vulnerabilities to County-owned HHPDs will automatically be given a HIGH priority as described in the overall mitigation action prioritization criteria in Section 7.6. The County Departments responsible for implementing the associated mitigation actions, along with the priority, potential funding source, and expected time frame are listed in Section 7.8.

6.7.13 Summary
Los Angeles County has 90 state -jurisdictional dams, with 70 classified as High or Extremely High hazard, meaning their failure could result in widespread loss of life and economic devastation. While regulatory oversight has improved dam safety, aging infrastructure, seismic threats, and increased storm intensity remain challenges.

Continued investment in retrofits, early warning systems, and emergency planning is essential to mitigating the risk of catastrophic dam failures.

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6.8 Land Movement

6.8.1 Nature
Land movement refers to the downward
movement of rock, soil, or debris along a
slope due to gravity. This process can occur
suddenly or gradually over time, depending
on contributing factors such as soil
composition, slope stability, and external
triggers. Land movement encompass a
variety of movement types including
mudflows, rockfalls, debris flows, land
slumps, land subsidence, and soil
movement. In Los Angeles County, the
diverse topography and geological
formations make certain areas more prone to
land movement, particularly during periods
of intense precipitation, seismic activity, or
human land-use modifications.

Climate change exacerbates land movement
by increasing the frequency and intensity of
extreme weather events, such as heavy rainfall and flooding, which can lead to accelerated erosion and heightened landslide risks.

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Land movement often occur in conjunction with other natural hazards, exacerbating their impact. Some of the primary contributing factors include:
• Seismic Activity: Earthquakes can destabilize slopes, leading to land movement and rockfalls. The force of seismic shaking can cause sudden failures, particularly in areas with pre-existing instability.
• Heavy Rainfall and Flooding : The likelihood of land movement increases after successive storms. Prolonged or intense rainfall saturates soil, reducing its cohesion and triggering slope failures.
• Coastal Erosion: Waves and storm surge erode coastal cliffs, leading to instability and eventual collapse, particularly in areas such as County beaches and coastal communities, many of which have previously experienced significant erosion. • Wildfires: Loss of vegetation due to fires reduces the soil’s ability to retain moisture, making slopes more susceptible to erosion and land movement during subsequent rain events.
• Burn Scars: Wildfire burn scars significantly elevate the risk of land movement by stripping the land of stabilizing vegetation. Areas affected by major fires such as the Woolsey Fire (2018), Bobcat Fire (2020), Bridge Fire (2024), Eaton Fire (2025), and Palisades Fire (2025) have shown increased susceptibility to land movement due to reduced soil stability and rapid runoff during rainstorms.

6.8.2 Location
Los Angeles County is home to multiple regions susceptible to land movement due to steep slopes, unstable geology, and weather patterns. The California Geological Survey (CGS) Landslide Susceptibility Map highlights high -risk areas. For a better visual representation of the Land Movement Hazard within the LA County planning area, please reference Appendix A for maps that show areas that are susceptible to land movement and recent burn scars.

Potential land movement areas include (but are not limited to):
• Santa Monica Mountains
• San Gabriel Mountains
• Sierra Pelona Mountains
• Baldwin Hills
• Puente Hills
• Palos Verdes Hills
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These areas are particularly vulnerable due to their steep terrains, weak rock formations, and history of slope movement. Additionally, human activities such as grading, excavation, and construction in these regions can further destabilize the ground, increasing the likelihood of land movement. Areas impacted by past wildfires, known as burn scars, are also highly susceptible to land movement, as the loss of vegetation reduces soil stability and increases erosion risks during heavy rains. This is particularly concerning in wildfire-prone areas such as the Santa Monica Mountains and the foothills of the San Gabriel Mountains, where post -fire land movement have historically caused significant damage.

6.8.3 Extent
The extent of land movement in Los Angeles is significant and varied, influenced by its unique geological setting. According to the 2011 CGS Landslide Susceptibility Map, approximately 750 square miles (15.75%) of Los Angeles County fall within high -risk landslide zones. The highest concentrations of deep-seated landslide susceptibility are distributed as follows:

Table 6-5 Landslide Susceptibility Map
Area High-Risk Landslide Zones
(sq. miles)
Percentage of Total Land
Area
Los Angeles County 750.02 15.75%
Unincorporated Areas 577.63 18.99%
Supervisorial District 1 17.29 7.02%
Supervisorial District 2 2.73 1.68%
Supervisorial District 3 114.61 26.58%
Supervisorial District 4 105.12 23.89%
Supervisorial District 5 509.31 18.14%

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6.8.4 History
Land movement have historically caused significant damage in Los Angeles County, often resulting in property destruction, infrastructure damage, and road closures. There have been no federal declarations or state proclamations for dam failure in the last five years. Some of the most notable events include:
• 1956 – Portuguese Bend Landslide: A massive landslide on the Palos Verdes Peninsula began in 1956 and remains active today. The movement of land has displaced homes and infrastructure, highlighting the region’s ongoing geologic instability.
• 1994 – Northridge Earthquake -Induced Land movement : The earthquake triggered more than 11,000 moving events, primarily in the Santa Susana Mountains and San Gabriel Mountains, causing extensive road and structural damage. • March 1995 – Pacific Palisades Landslide: Heavy rains weakened the coastal bluffs, leading to a 300 -foot-w i d e c o l l a p s e t h a t b u r i e d p a r t o f t h e P a c i fi c C o a s t Highway under 30 feet of debris.
• March 2005 – Sunset Mesa Landslide: A slope failure near Malibu caused over 20,000 cubic yards of debris to block roadways and damage property. • July 2023 – Peartree Lane Land Movement (Rolling Hills Estates) : A sudden slope failure resulted in the displacement of 12 homes, which were red-tagged due to structural instability.
• September 2024 – Accelerated Land Movement in Rancho Palos Verdes : A significant increase in land movement, with certain areas shifting up to four inches per week toward the ocean, threatening roads and over 250 residential properties.

6.8.5 Types of Land Movement
Debris Flow/ Mudflow/ Soil Movement
Debris flow involves the rapid movement of a dense mixture of water , soil, rock, and organic material down a slope. This process can have significant impacts on landscapes, ecosystems, and human infrastructure.

Debris flows are characterized by their fluid-like behavior and ability to transport large objects, such as boulders and trees. They can travel at high speeds making them highly destructive. The composition of a debris flow can vary, but it typically includes:

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• Water: A crucial component that facilitates movement. • Soil and Rock: These provide the bulk of the material in a debris flow. • Organic Material: Includes vegetation and other natural debris that get caught in the flow.

Mudflows are rapid movements of water -saturated earth materials that can cause significant damage to both natural environments and human settlements. Mudflows are characterized by their fluid -like motion, which occurs when soil, rocks, and debris become saturated with water. This saturation reduces the friction between particles, allowing the mass to move downhill under the influence of gravity. Key characteristics include:
• Speed and Volume: Mud flows can travel at speeds up to 35 miles per hour and can carry large volumes of material, including rocks, trees, and even vehicles. • Consistency: The consistency of a mud flow can vary from a thick, viscous slurry to a watery flow. This depends on the proportion of water to solid materials. • Path: Mud flows typically follow existing drainage patterns, such as river channels and valleys, but can also carve new paths, leading to unpredictable and widespread damage.

Soil movement is a natural process that significantly impacts the environment and human activities. It involves the displacement of soil particles due to various natural and human caused factors. Key characteristics include:
• Landslides: Often occurring in hilly areas, landslides involve the downward movement of rock and soil. They can be sudden and fast -moving, making them particularly dangerous.
• Soil Creep: T h i s i s a s l o w a n d g r a d u a l m o v e m e n t o f s o i l d o w n a s l o p e , o f t e n unnoticed until significant damage occurs.
• Soil Liquefaction: During an earthquake, saturated soil can temporarily lose its strength and behave like a liquid, causing structures to sink or tilt.

Causes
In Los Angeles County, several factors contribute to the occurrence of debris flows/mudflows/ soil movement:
• Heavy Rainfall and Storm Events: Intense and prolonged rainfall, often associated with storms, can saturate the soil, reducing its stability and triggering debris flows.

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The region's Mediterranean climate, with wet winters and dry summers, creates conditions conducive to such events.
• Wildfires: Los Angeles County frequently experiences wildfires, which can burn and destabilize vegetation that normally helps hold soil in place. The loss of vegetation increases the risk of soil erosion and, consequently, debris flows during subsequent rainfalls.
• Steep Terrain: The county's mountainous terrain, including areas like County mountainous areas, is particularly prone to debris flow. The steep slopes facilitate the rapid movement of debris downhill.
• Soil Composition: Certain soil types, such as clay -rich soils, can become highly unstable when saturated with water, making them more susceptible to debris flow. • Human Activity: Urban development, road construction, and deforestation can alter natural landscapes and exacerbate conditions that lead to debris flow. • Seismic Activity: Los Angeles County is situated in a highly active seismic zone, making it prone to earthquakes. Seismic activity can lead to soil liquefaction, landslides, and ground shaking, all contributing to soil displacement.

Land Subsidence
Land subsidence is a gradual settling or sudden sinking of the Earth's surface due to various natural and human-induced factors. This hazard can have significant impacts on the environment, infrastructure, and communities.

A reduction in land elevation is one of the most noticeable features of land subsidence, leading to significant changes in the landscape. This phenomenon can occur due to natural processes, such as the dissolution of limestone, as well as human activities like the excessive extraction of groundwater, oil, or natural gas. Furthermore, land subsidence increases the risk of flooding because the lower elevation can lead to poor drainage and water accumulation. As the ground sinks, it often results in the formation of depressions, fissures, and sinkholes, which can dramatically alter the geography and infrastructure of the area.
• Depressions: Are sunken or low-lying areas on the Earth’s surface, often formed by natural or man-made processes.
• Fissures: Are a long, narrow crack or linear opening in the Earth’s crust. • Sinkholes: Are holes in the ground causes by the collapse or sinking of surface material into an underlying void.

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Causes
• Groundwater Extraction: One of the primary causes of land subsidence in Los Angeles County is the excessive extraction of groundwater. As water is pumped out of underground aquifers, the ground above can sink or settle, leading to subsidence.
• Oil and Gas Extraction: The removal of oil and natural gas from beneath the earth's surface also contributes to land subsidence. This extraction can create voids and reduce pressure in subterranean layers, causing the ground to sink. • Natural Soil Compaction: Over time, natural processes such as soil compaction can lead to gradual subsidence. In areas with loose or unconsolidated soils, the weight of overlying materials compacts the ground, resulting in a lowering of the land surface.

Rock Falls
Rock falls are a natural geological phenomenon where rock fragments break free from a steep slope or cliff and tumble downward. These events can range from small pebbles dislodging to massive boulders crashing down with significant force and impact.

Rock falls are characterized by:
• Speed and Suddenness: Rock falls occur quickly and without much warning, making them particularly dangerous.
• Varied Sizes: The size of the falling material can range from small pebbles to large boulders, impacting the severity of the event.
• Path Predictability: While the initial trigger point is often identifiable, the path of descent can be unpredictable due to varying terrain and obstacles.

Causes

The primary causes of rock falls include:
• Weathering and Erosion: Over time, weathering processes such as freeze-thaw cycles, chemical weathering, and the action of water can weaken rock structures.

Erosion can undermine the base of slopes, making rocks more susceptible to falling. • Seismic Activity: Los Angeles County is located in a seismically active region.

Earthquakes can dislodge rocks from cliffs and steep slopes, triggering rock falls.

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• Heavy Rainfall: Intense or prolonged rainfall can saturate the ground, increasing the weight and pressure on rock faces. This saturation can lead to the loosening and collapse of rocks.
• Human Activity: Construction, mining, and other human activities can destabilize rock formations. The vibrations from heavy machinery and blasting can initiate rock falls.

6.8.6 Probability
Landslides and other land movement events happen in Los Angeles County fairly often, especially after heavy rain or in areas that recently had wildfires or are prone to sliding. • Small landslides (like debris flows) are most likely during years with heavy rain, especially El Niño years. These happen every 2 to 7 years; there is 14% to 50% chance each year during those cycles.
• In high -risk zones (like steep mountain slopes with a history of movement), probability is 1–2% chance per year, especially following multi-year wet periods or major wildfires.
• Some areas of the County have been experiencing continuous sliding.

6.8.7 Vulnerability
Land movement pose risks to life, property, and essential infrastructure. The 2024 THIRA projects that approximately 1.2 million residents in Los Angeles County could be directly or indirectly affected by land movement. The most at -risk populations include:
• Residents of hillside and canyon communities such as Malibu, Topanga, and the Palos Verdes Peninsula.
• Homeowners in coastal bluff areas that are facing erosion-driven slope failures. • C o m m u n i t i e s i n w i l d fi r e b u r n s c a r a r e a s , w h e r e t h e l o s s o f v e g e t a t i o n i n c r e a s e s landslide probability during heavy rains.
• The Access and Functional Needs (AFN) community who may face challenges in evacuating or leaving landslide-prone areas.

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Contextual Overview
Los Angeles County’s diverse topography includes many hillside communities susceptible to deep -seated landslides, especially after wildfire or heavy rain. These hazards can isolate communities, damage property, and disrupt lifelines.

Extent of Exposure
• Total Area Exposed: 284.57 sq mi
• Supervisorial Districts (SD) Impacted:
o SD5: 151.96 sq mi (5.41%)
o SD3: 90.23 sq mi (20.93%)
o SD4: 25.94 sq mi (12.20%)
o SD1: 13.77 sq mi (3.90%)
o SD2: 2.68 sq mi (0.74%)
• Critical Facilities Affected:
o Fire Department: 41 (12.17%)
o Public Works: 32 (13.91%)
o Health Services: 12 (18.46%)
o Public Health: 4 (10.00%)
o Libraries: 9 (10.34%)
o Parks: 27 (14.92%)
o Education: 8 (9.76%)
Problem Statement
Landslides pose a serious risk to hillside communities and access routes, especially in areas recovering from wildfire. Current development and road infrastructure may not be resilient against slope failure. Mitigation actions should include slope stabiliz ation, targeted buyouts or relocations, and early warning systems.

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6.8.8 Impacts
Los Angeles County's diverse landscape and dense population make it highly susceptible to the effects of land movement, affecting critical infrastructure and raising significant economic, social, and safety concerns.

Transportation Networks
Los Angeles County's extensive transportation network is vital for daily commutes, goods transport, and emergency services. Land movement can severely impact these systems:
• Road Damage: Causes closures, hazardous driving conditions and costly repairs , as seen annually on Pacific Coast Highway (PCH), and many other local roads. • Bridge Compromise: Affects structural integrity, necessitating closures and expensive reconstructions.
• Public Transit Disruptions: Impacts train tracks and bus routes, leading to delays and service interruptions.
• Rail Systems: Track misalignment can cause delays and potential derailments, affecting both passenger and freight lines.

Water Supply Systems
The county's water delivery system is complex and vulnerable to land movement:
• Compromised Pipelines : Leads to ruptures or leaks, disrupting supply and requiring major repairs.
• Reservoir Impact: Landslides can affect water quality and storage capacity.

Energy Infrastructure
Land movement poses risks to Los Angeles County's energy infrastructure, including:
• Electrical Grid Vulnerabilities: Land movement can damage power lines and substations, causing outages.
• Gas Pipeline Risks: Soil shifts can result in gas leaks or explosions, endangering safety.

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Communication Systems
Reliable communication is critical, and land movement can disrupt:
• Telecommunication Towers: Structural damage can impair cellular and internet services.
• Underground Cables: Earth shifts can damage cables, affecting connectivity.

Emergency Services Facilities
• Hospitals and Fire Stations: Essential for emergency response, but structural damage could impede operations, underscoring the need for resilient construction and strategic planning.

Economic Impacts
• Infrastructure Damage: Leads to costly repairs and maintenance of roads, bridges, and buildings.
• Property Loss: Homeowners face financial losses due to property damage or devaluation.

Environmental Impacts
• Ecosystem Disruption: Soil movement can lead to habitat loss and affect local flora and fauna.
• Increased Pollution: Erosion can result in sediment runoff, degrading water quality in rivers and oceans.

For a better visual representation of the Land Movement Hazard within the LA County planning area, please reference Appendix A for maps that show areas that are susceptible to land movement and recent burn scars.

6.8.9 Mitigation Strategies
To reduce the impact of land movement, Los Angeles County has implemented several mitigation and preparedness strategies, including:
• Land Use and Development Regulations: Restricting development in high -risk landslide zones to prevent new structures from being built on unstable terrain. • Infrastructure Resilience: Reinforcing existing infrastructure through slope stabilization projects, retaining walls, and improved drainage systems.

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• Stabilization Regulations: Implementing stricter grading and excavation regulations to minimize the destabilization of slopes.
• Public Awareness Campaigns: Enhancing landslide early notifications by monitoring potential movement areas and precipitation thresholds. • Evacuation Planning: Developing evacuation plans for at -risk communities, ensuring residents receive timely alerts and clear guidance. • Public Education: Conducting public education campaigns to inform residents about recognizing landslide warning signs and preparedness measures. • Operational Area Coordination: Increasing coordination across state, federal, and Office of Emergency Management officials with local jurisdictions to improve forecasting and response efforts.

6.8.10 Summary
Land movement remains a significant hazard in Los Angeles County, particularly in steep and coastal regions. The Palos Verdes Peninsula, Santa Monica Mountains, and San Gabriel Mountains are among the most vulnerable areas, with climate change and human activities exacerbating risks. By implementing land -use regulations, infrastructure reinforcements, and emergency response improvements, the County can enhance resilience and reduce losses in the future. Local governments and communities must actively monitor and manage contributing factors to effectively mitigate the impacts of land subsidence.

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6.9 Tsunami

6.9.1 Nature
This section characterizes tsunamis as
high-energy, long-wavelength ocean
waves generated primarily by
significant offshore seismic events
(such as subduction zone
earthquakes), submarine landslides,
or volcanic eruptions. In the context of
Los Angeles County, tsunamis
represent a relatively infrequent but
potentially high -impact hazard that
could produce rapid coastal
inundation and surge impacts.

Characteristics:
• Triggered mainly by distant, large-
magnitude seismic events.
• Features long wavelengths and prolonged arrival times. • Capable of producing rapid, deep inundation along low-lying coastal areas. • In summary, tsunamis are dynamic natural phenomena with the potential to cause sudden coastal flooding and damage if a triggering event occurs.

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6.9.2 Location
The updated tsunami hazard profile focuses on the coastal areas of Los Angeles County. The new zone map —developed using enhanced modeling techniques and updated coastal geomorphology data—highlights areas along the Pacific shoreline that are at risk. These include regions adjacent to the Los Angeles Basin, parts of Long Beach, Santa Monica Bay, and other low-elevation coastal zones.

For a better visual representation of Tsunami Inundation zones within the LA County planning area, please reference Appendix A for a “Tsunami Inundation Area” map.

Important Details:
• Coastal segments from the western margins of the Los Angeles Basin extending to the border with Orange County.

Overall, the coastal areas of Los Angeles County, containing our communities and infrastructure, face heightened exposure.

6.9.3 Extent
Using the latest hydrodynamic and inundation modeling, the updated tsunami inundation (zone) map provides a refined view of the extent of potential flooding. The map illustrates how tsunami waves could propagate inland, showing revised boundaries that account for current sea -level conditions and future sea -level rise projections.

Highlights:
• Inundation depths and reach have been recalculated, with some areas potentially experiencing water levels up to several feet in depth.
• The inland reach of flooding varies by local topography , with flat, low-lying areas showing the greatest potential for impacts . I m p a c t e d a r e a s i n c l u d e , b u t a r e n o t limited to, Long Beach, The ports of Long Beach and Los Angeles, Marina del Rey, Venice and Santa Monica.
• Critical infrastructure within the updated zones has been identified to prioritize mitigation and evacuation routes for planning.

In essence, the extent of tsunami impacts is now mapped more precisely, offering local decision-makers a clearer view of potential flooding depths and distances inland.

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6.9.4 History
Historically, significant tsunami events in the Los Angeles region are rare, though distant seismic events (for example: the 1960 Chilean tsunami, or the most recent 2022 Tonga tsunami) have been known to produce measurable impacts. Historical records combined with geological studies indicate that while tsunamis have occurred in the past, their frequency is low compared to other hazards. However, the region’s proximity to major tectonic boundaries necessitates ongoing vigilance.

Historical Context:
• Past events have been sporadic but can serve as valuable lessons for preparedness. • Historical inundation records and sediment studies confirm that tsunamis have reached the Los Angeles coast in prehistory.
• Lessons learned from past minor events underscore the importance of maintaining updated hazard maps.

Thus, while historical tsunami events are infrequent, they provide a critical context for understanding future risks and guiding preparedness measures. There have been no federal declarations or state proclamations for tsunami in the last five years.

6.9.5 Probability
The probability of a tsunami affecting Los Angeles County is generally low when compared to more frequent hazards like earthquakes or floods. Nevertheless, the potential for a distance source tsunami generated by a distant, large seismic event remains a realistic risk. Updated probabilistic assessments—incorporating recent seismic data and tsunami modeling indicate that while the overall likelihood is low, the consequences in the event of a tsunami can be severe.

Probability Considerations:
• Low annual probability but high consequence if an event occurs ; Los Angeles County has about a 2% annual chance.
• Distance source events from subduction zones across the ocean contribute most to the risk.
• Continuous monitoring and updated modeling are essential to reassess the risk over time.
• In summary, the probability of a tsunami remains low, but due to the potential for high-impact outcomes, it warrants continuous study and preparedness.

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6.9.6 Vulnerability
Coastal vulnerability in Los Angeles County is significantly influenced by factors such as urban density, low -elevation terrain, aging infrastructure, and socio-economic conditions. The updated tsunami zone map now better delineates areas where these vulnerabilities are most pronounced, highlighting communities that may have limited evacuation routes and fewer resources to recover from rapid inundation. About 75,000 people live in parts of Los Angeles County that could be flooded by a tsunami. Many people a lso work in these coastal areas, and around 660 unhoused individuals live there, making them especially at risk because they may not have easy access to shelter or transportation.

Tourism adds even more people to these areas, especially during busy weekends or holidays. Places like Santa Monica can see up to 300,000 visitors a day during peak times. This makes evacuating harder if a tsunami warning is issued. Roads near the coast can quickly become crowded, and visitors may not know the best way to leave.

Traffic could slow down emergency plans, so it’s important to have clear signs, early warnings, and good traffic control to help people get to safety quickly.

Factors:
• High population density in low-lying coastal areas.
• Critical infrastructure (e.g., hospitals, utilities, ports and shipping, transportation networks) located within the inundation zones.
• Socio-economic and language barriers that may hinder effective emergency response.
• Limited natural barriers in some coastal segments.
• Vulnerable communities include those with high population densities and critical infrastructure near the coast.

Ultimately, the vulnerability of the region is compounded by both physical exposures and social factors, underscoring the need for targeted mitigation efforts.

Contextual Overview
Coastal communities in Los Angeles County, including ports and tourist zones, are at risk from tsunamis. These rare but highly destructive events can inundate coastal infrastructure with little warning.

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Extent of Exposure
• Total Area Exposed: 32.89 sq mi
• Supervisorial Districts (SD) Impacted:
o SD4: 15.83 sq mi (7.43%)
o SD3: 12.59 sq mi (2.92%)
o SD2: 2.03 sq mi (0.56%)
• Critical Facilities Affected:
o Fire Department: 16 (4.75%)
o Public Works: 9 (3.91%)
o Health Services: 3 (4.62%)
o Public Health: 1 (2.50%)
o Libraries: 5 (5.75%)
o Parks: 13 (7.26%)
o Education: 3 (3.66%)
Problem Statement
Tsunamis can cause rapid and catastrophic coastal flooding. With critical coastal infrastructure and residential areas exposed, especially in SD4 and SD3, there is a need for robust evacuation planning, vertical evacuation shelters, and community outreach to enhance preparedness and reduce vulnerability.

6.9.7 Impacts
Should a tsunami occur, the potential impacts on Los Angeles County could be extensive. Parts of Los Angeles County that could be impacted by a Tsunami are Marina Del Rey, Port of Los Angeles, Port of Long Beach, and other beach communities in low lying areas. The updated impact assessments reflect possible scenarios ranging from significant property damage to loss of life and long-term economic disruption. The new zone map aids in quantifying these impacts by providing detailed inundation depths and spatial extents, thereby allowing for better risk communication and planning.

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Potential Impacts:
• Severe flooding of coastal infrastructure and residential areas. • Disruption of transportation, utility services, and emergency response operations. • Economic losses in key sectors such as tourism, shipping, and local commerce. • Social impacts including displacement, loss of livelihoods, and challenges in emergency sheltering.

I n s h o r t , t h e p o t e n t i a l i m p a c t s o f a t s u n a m i a r e f a r-reaching, necessitating robust mitigation, evacuation, and recovery planning to minimize harm.

For a better visual representation of Tsunami Inundation zones within the LA County planning area, please reference Appendix A for a “Tsunami Inundation Area” map.

6.9.8 Summary
The updated tsunami section for the 202 5 AHMP incorporates the latest scientific findings and mapping techniques to provide a more precise understanding of tsunami risks in Los Angeles County. By integrating an updated inundation zone map, the revision clarifies the spatial extent of potential floodi ng and highlights the vulnerabilities in coastal communities. This comprehensive update is designed to guide decision-makers in enhancing preparedness, targeting mitigation strategies, and strengthening community resilience.

Key Takeaways:
• Nature: Tsunamis are infrequent but high -energy events capable of rapid coastal inundation.
• Location & Extent: The updated zone map identifies vulnerable coastal areas with revised inland flood extents.
• History & Probability: Historical events are rare; however, distance events remain a realistic risk.
• Vulnerability & Impacts: High population density and critical infrastructure in coastal zones amplify risk, with potential for severe economic and social disruption.

This updated section is intended to serve as a critical tool for policymakers, emergency managers, and community stakeholders as they work together to reduce the long-term risks associated with tsunamis and enhance overall regional resilience.

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6.10 Severe Wind and Tornado

6.10.1 Nature
Severe wind and tornadoes pose
significant threats to life, property, and
infrastructure, though they differ in
frequency and intensity within Los Angeles
County. Severe wind events, particularly
Santa Ana winds, are a recurring natural
hazard that can cau se widespread
damage, including downed power lines,
tree falls, and structural damage. These
winds originate from high -pressure
systems over the Great Basin, funneling dry
and warm air through mountain passes into
the coastal and valley regions at high
speeds. Additionally, storm -driven winds,
microbursts, straight-line winds and gust
fronts associated with severe weather can
create hazardous conditions, often leading
to transportation disruptions, fire hazards,
and prolonged power outages.

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Tornadoes, while relatively rare in the region, have been recorded and can cause localized but intense damage. These violent windstorms form when unstable atmospheric conditions produce rotating updrafts, resulting in a funnel cloud that contacts the ground.

6.10.2 Location
Severe wind events affect the entire Los Angeles County planning area, with the strongest occurrences in canyon passes, valleys, and coastal regions. The Santa Ana winds are most intense in the fall and winter months, particularly impacting areas in the Valley, and foothill communities of the County. Storm-driven winds, on the other hand, can impact any part of the county and vary in intensity based on weather patterns.

T h e s e w i n d s c a n r e a c h s p e e d s o f 6 0 t o 8 0 m p h , s o m e t i m e s e x c e e d i n g t h o s e thresholds, leading to significant damage.

Tornadoes are more sporadic in occurrence and can develop in various parts of the county, particularly in lowland areas where severe thunderstorms have the potential to form rotating systems.

6.10.3 Extent
Winds and breezes are common occurrences in LA County. As wind speeds increase so does the potential for a catastrophic event. Hot dry winds can reach high speeds as they descend from the inland desert regions, creating not only critical wind events but also extremely dangerous fire conditions and contributing to the spread of wildfires.

The winds are classified in the Beaufort Wind Scale, see Figure 6.10.1 below. Beaufort wind scale is an empirical scale that relates wind speed to observed conditions at se a or land. It uses numerical scale from 1 -12 to describe wind force based on visual observations of the effects of the wind and gives quantitative measures of the wind. For example, o is described as ‘calm’ a sea like a mirror while 12 described as hurrica ne force with devastating conditions.

Tornadoes are classified using the Enhanced Fujita (EF) Scale Figure 6.10.2. The Enhanced Fujita (EF) Scale is specifically used to rate the intensity of tornados based on the damage they cause (damage indicators) such as building types, and trees. It ranges from EF -0 to EF -5, with increasing numbers indicate stronger tornados an d more severe damage. While tornadoes in the region typically do not exceed EF -1 County of Los Angeles
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intensity, they can still produce damaging winds above 100 mph, capable of tearing roofs off buildings, uprooting trees, and overturning vehicles.

Beaufort Wind Scale:

Force
Wind
(Knots)
WMO
Classification
Appearance of Wind Effects
On the Water On Land
0 Less
than 1 Calm Sea surface smooth and
mirror-like
Calm, smoke rises
vertically
1 1-3 Light Air Scaly ripples, no foam crests
Smoke drift indicates
wind direction, still wind
vanes
2 4-6 Light Breeze Small wavelets, crests glassy,
no breaking
Wind felt on face, leaves
rustle, vanes begin to
move
3 7-10 Gentle
Breeze
Large wavelets, crests begin
to break, scattered whitecaps

Leaves and small twigs
constantly moving, light
flags extended
4 11-16 Moderate
Breeze
Small waves 1-4 ft. becoming
longer, numerous whitecaps
Dust, leaves, and loose
paper lifted, small tree
branches move
5 17-21 Fresh Breeze
Moderate waves 4-8 ft taking
longer form, many whitecaps,
some spray
Small trees in leaf begin
to sway
6 22-27 Strong
Breeze
Larger waves 8-13 ft,
whitecaps common, more
spray
Larger tree branches
moving, whistling in
wires
7 28-33 Near Gale
Sea heaps up, waves 13-19 ft,
white foam streaks off
breakers
Whole trees moving,
resistance felt walking
against wind
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8 34-40 Gale
Moderately high (18-25 ft)
waves of greater length,
edges of crests begin to
break into spindrift, foam
blown in streaks
Twigs breaking off trees,
generally impedes
progress
9 41-47 Strong Gale
High waves (23-32 ft), sea
begins to roll, dense streaks
of foam, spray may reduce
visibility
Slight structural damage
occurs, slate blows off
roofs
10 48-55 Storm
Very high waves (29-41 ft)
with overhanging crests, sea
white with densely blown
foam, heavy rolling, lowered
visibility
Seldom experienced on
land, trees broken or
uprooted, "considerable
structural damage"
11 56-63 Violent Storm
Exceptionally high (37-52 ft)
waves, foam patches cover
sea, visibility more reduced

12 64+ Hurricane
Air filled with foam, waves
over 45 ft, sea completely
white with driving spray,
visibility greatly reduced

Figure 6.10.1 Beaufort Wind Scale

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Enhanced Fujita Scale:

THE ENHANCED FUJITA SCALE (EF SCALE)
EF RATING 3 Second Gust (MPH) DAMAGE
EF 0 65-85 MPH Light: Branches broken,
minor roof damage
EF 1 86-110 MPH Moderate: Roofs
damaged; trees uprooted
EF 2 111-135 MPH Considerable: Roofs torn
off, large trees down
EF 3 136-165 MPH Severe: Homes destroyed;
cars lifted
EF 4 166-200 MPH Devastating: Houses
leveled; debris airborne
EF 5 Over 200 MPH Incredible: Homes swept
away; total destruction

6.10.4 History
Los Angeles County has experienced multiple severe wind events and occasional tornadoes in recent history which caused destructions, and wildfires. There have been no federal declarations or state proclamations for Severe Wind & Tornadoes in the last five years. Some notable incidents include:
• November-December 2011: A wind event caused mor e than $35 million in damages and severely impacted several foothill communities and unincorporated areas.
• December 2019: An EF-0 tornado touched down in South Los Angeles, causing minor roof damage and downing power lines.
• January 2021: A severe windstorm impacted the region, leading to damage across multiple communities and emergency response efforts to clear roadways. • September 2021: An EF-0 tornado developed near the community Lake of Los Angeles; %no damage was reported.

Figure 6.10.2 Enhanced Fujita Scale

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• April 2023: An EF-0 tornado recorded in Cerritos causing tree damage. • March 2023 (DR# 4699 ): An EF-1 tornado struck Montebello, one of the strongest tornadoes recorded in the area, causing significant damage to commercial structures and vehicles.
• May 2023: An EF -0 tornado occurred near the communities of Carson and Compton damaging buildings and vehicles.
• August 2023 ( DR# 4750 ): Tropical Storm Hillary impacting Los Angeles County.
• February 2024: Strong winds impacting across Eastern Santa Monica Mountain and Santa Clarita Valley.
• March 2024: Strong winds impacting areas around San Gabriel Valley. • January 2025 (DR# 4856): A severe windstorm impacted the region, leading to a Potentially Dangerous Situation (PDS), red flag conditions. Several fires broke out in the area, which exhibited extreme fire behavior, causing widespread destruction.
• March 2025 (DR# 4856): As part of a storm event, an EF-0 tornado struck Pico Rivera, California, at 3:15am, with wind speeds reaching up to 85 mph.

6.10.5 Probability
Severe wind events are a regular occurrence in Los Angeles County, with a h igh probability, 99% chance recurring annually. Santa Ana winds are particularly common during the cooler months, and climate patterns suggest that extreme wind events may become more frequent due to changing weather dynamics. Because wind events and tornados are localized in nature, probability vary from one area to another and is difficult to determine percentage of happening in one area. Tornadoes remain a low- probability hazard, 10% chance, in the planning area; however, given past occurrences, they cannot be ruled out entirely. Atmospheric conditions capable of producing tornadoes may arise during severe thunderstorms, particularly in winter storm systems that generate strong wind shear. While the likelihood of an EF-2 or stronger tornado is minimal, the potential for localized damage remains. The Santa Ana winds occur ten to twenty-five times annually and can last for several days, posing a recurring threat of damage and disruption in Los Angeles County.

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6.10.6 Vulnerability
Severe wind and tornadoes can be extensive, affecting both infrastructure and public safety. High-wind events pose a risk to critical infrastructure, particularly power lines, communication systems, and transportation networks. Buildings, especially older structures and mobile homes, are vulnerable to wind -related damage, including roof failures, window breakage, and structural collapse.

In addition to physical damage, severe wind events can cause significant economic disruptions. Prolonged power outages impact businesses, healthcare facilities, and emergency response services. Road closures and debris blockages hinder mobility and commerce, while wind -driven wildfires, a secondary hazard of Santa Ana winds, can lead to devastating losses.

Public safety is also a major concern, with risks of flying debris, vehicle accidents, overturned vehicles, and respiratory issues caused by airborne dust and pollutants stirred up by high winds.

Severe wind and tornado events disproportionately impact certain populations and infrastructure in Los Angeles County due to both geographic exposure and socioeconomic vulnerabilities. These hazards can disrupt critical services, exacerbate existing inequalities, and significantly damage structures not built to withstand extreme wind conditions.

Vulnerable Populations
Out of the county’s estimated 10.2 million residents, the following populations are considered especially vulnerable:
• Older Adults (65+): Approx. 1.6 million residents (15.5%)—more likely to suffer injury or health complications during wind -related power outages and evacuation events.
• Access and Functional Needs (AFN) Populations: Estimated 1.7 million individuals (17%) including those with disabilities, limited mobility, or communication barriers.
• Low-Income Households: Over 13% of households fall below the poverty line and may lack the resources for structural mitigation or relocation during prolonged outages.

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• People Experiencing Homelessness (PEH): Over 75,000 individuals (2024 LAHSA count), at direct risk from falling debris and lack of shelter during windstorms.
• Mobile Home Residents: Approximately 98,000 units countywide, concentrated in inland valleys and foothill communities that are highly exposed to Santa Ana winds.
• Children Under Age 5: Around 600,000 countywide, vulnerable to respiratory complications from airborne particulates and debris stirred by strong winds. • Economic Impact: Business disruptions, increased insurance claims, and the costs of emergency response and recovery add financial burdens to local communities.

Critical Infrastructure at Risk
Severe wind and tornado events can cause widespread cascading failures in vital systems, including:
• Power Infrastructure: Los Angeles County contains over 20,000 miles of overhead power lines vulnerable to high-wind damage and fire ignition. • Medical Facilities: Over 350 licensed hospitals and health clinics, many reliant on uninterrupted power and access for vulnerable patient populations. • Transportation Corridors: Major highways (I-5, I -10, US -101) and over 3,100 bridges, particularly in canyon and foothill areas, are susceptible to obstruction by fallen trees and debris.
• Communication Towers: Over 800 critical telecom sites serve the county’s emergency communications and can be disrupted by high wind gusts. • Schools: Approximately 2,300 public K–12 schools and 100+ college campuses face operational disruptions from power outages or infrastructure damage during events.

6.10.7 Impacts
Severe wind and tornado events pose significant threats to critical infrastructure, public safety, and community operations in Los Angeles County. High winds, such as those during Santa Ana events, regularly damage power lines, uproot trees, and disable County of Los Angeles
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transportation corridors. A notable example occurred in January 2025, when widespread windstorms caused power outages for more than 200,000 customers, including approximately 127,000 Los Angeles Department of Water and Power (LADWP) customers and over 52,000 Southern California Edison (SCE) customers.

During this same period, wildfires exacerbated by the strong winds impacted several medical facilities, disrupting critical health services and requiring the emergency relocation of patients.

Tornadoes, while rare, have also demonstrated destructive capacity in localized areas.

In March 2025, an EF-0 tornado touched down in Pico Rivera, downing power lines and trees and obstructing roadways, highlighting the potential for tornadic activity to impact urban communities. These hazards not only endanger life and property but also threaten economic continuity and the functioning of emergency services, particularly in vulnerable neighborhoods and areas with aging infrastructure.

6.10.8 Mitigation and Preparedness
Efforts to mitigate the effects of severe wind and tornadoes should focus on improving structural resilience, enhancing early warnings and alerts, and increasing public awareness of such events.

Severe Wind and Tornado Mitigation
• Strengthening building codes to require wind -resistant design features.

Promoting the use of wind -resistant materials and construction techniques in new developments.
• Conducting regular tree-trimming and vegetation management to reduce infrastructure damage risks.
• Retrofitting and reinforcing critical infrastructure, such as power lines and utility systems, to withstand high-wind conditions.
• Implementing public education campaigns on windstorm preparedness and safety measures.
• Leveraging early warning alerting and preparedness messaging, as well as integrating emergency messaging with local broadcast and mobile networks.

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6.10.9 Summary
Severe wind and tornadoes, though differing in frequency, remain potential hazards for Los Angeles County. Santa Ana winds and storm -driven gusts regularly impact the region, causing damage to infrastructure and increasing wildfire risks. While tornadoes are rare, their occasional occurrence necessitates preparedness and mitigation efforts.

By implementing stronger building codes, reinforcing critical infrastructure, and enhancing preparedness and public awareness, the county can reduce its vulnerability to these hazards, helps to better protect its residents from potential hazards of severe winds and tornado and improve community resilience.

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6.11 Mass Violence

6.11.1 Nature
This section outlines the defining
characteristics of mass violence,
which includes intentional, high -
impact incidents such as terrorism,
active shooter events, vehicle-
rammings, and other coordinated
attacks. Understanding the nature of
these events is cr itical for
developing effective mitigation
strategies.
• Mass violence includes both
targeted attacks (e.g.,
ideologically motivated
terrorism) and opportunistic
acts (e.g., active shooters or
violent assaults in public
spaces).
• These incidents are characterized by their low warning time, high lethality, and potential to incite widespread fear and panic.

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• Acts of mass violence
may be perpetrated by
individuals, small groups,
or well-organized
networks, and can
involve firearms,
explosives, vehicles, or
biological agents.
• These attacks often aim
to disrupt societal
functions, damage
infrastructure, or exploit
vulnerabilities in soft
targets such as schools,
places of worship, or
entertainment venues.

In summary, the nature of mass
violence lies in its deliberate
intent to inflict harm on groups
and disrupt public order,
making strong mitigation
measures essential for
protecting life and property of
Los Angeles County.

6.11.2 Extent
The potential extent of mass
violence is characterized by its
ability to cause widespread
disruption and significant loss of
life and property.

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• Events can result in many casualties and severe physical and psychological impacts.
• Mass violence can disrupt essential services, strain emergency response systems, and create cascading socioeconomic effects.
• The overall disruption may extend far beyond the immediate scene, affecting broader community resilience.

In essence, while these events may be rare, their extensive impacts necessitate comprehensive planning and resilient infrastructure.

6.11.3 History
Historical data illustrates that mass violence has evolved over time, with earlier events shaping current mitigation strategies and more recent incidents underscoring emerging vulnerabilities. Previous mitigation and other plans referenced events such as large-scale terrorist attacks and active shooter incidents. • Recent events in the last five years include high -profile active shooter incidents at schools, public transportation hubs, and commercial centers, as well as vehicle-ramming attacks in urban areas.

Overall, the historical trend shows that while frequency remains low, the severity of mass violence incidents has escalated, necessitating continual updates to mitigation strategies.

6.11.4 Location
Mass violence incidents tend to occur in areas where people naturally congregate, including urban centers, transportation hubs, educational and religious institutions, shopping centers, and public events and venues.
• Public spaces such as transit stations, stadiums, malls and other locations where large number of people assemble, are considered higher-risk areas. • Critical infrastructure location , like government buildings and commercial center, are often targeted.
• Certain events may also occur in areas lacking adequate physical security or surveillance.

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Thus, identifying and securing high -density locations is a key focus for mitigating the effects of mass violence.

6.11.5 Probability
The probability of mass violence incidents is difficult to predict precisely; however, the potential for occurrence is recognized as a persistent low -frequency, high-impact risk that requires constant vigilance.
• Such incidents are statistically rare yet present a disproportionate risk due to their catastrophic consequences.
• Threat assessments and intelligence reports indicate that evolving tactics may increase probability over time.
• Continuous monitoring and updated threat analyses (e.g., via THIRA processes) are essential in quantifying risk levels.

In summary, while mass violence events are not common, their inherent unpredictability and high severity demand that communities prepare as if an incident could occur at any time.

6.11.6 Vulnerability
Mass violence depends on a variety of factors, including physical infrastructure design, public awareness, security preparedness, and interagency coordination. • Critical vulnerabilities include open public spaces with minimal physical barriers or limited or ineffective safety / security protocols in place. •  Gaps in training and preparedness among first responders can exacerbate the situation during an active incident.
• Social vulnerabilities —such as communication gaps or lack of multilingual emergency information—may hinder rapid response and community resilience.

Thus, reducing vulnerability involves investing in infrastructure hardening, robust security measures, regular training exercises, and effective public communication strategies.

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6.11.7 Impacts
The impacts of mass violence events are multifaceted, life safety, community stability, and the local economy.
• Immediate impacts include fatalities, injuries, and trauma among affected populations.
• Secondary impacts may encompass prolonged disruption of local services, economic downturns, and lasting psychological effects on communities. • Long-term consequences can involve extensive resource allocation for recovery and mitigation, further straining public systems.

Mass violence inflicts immediate harm and often triggers a chain of secondary impacts that complicate community recovery and strain long-term resilience efforts.

6.11.8 Summary
In conclusion, mitigating the hazards of mass violence requires an integrated, multi - layered approach that spans prevention, preparedness, response and recovery .

Communities must implement measures to secure high -risk locations, upgrade physical and digital security, enhance interagency coordination, and continuously update training and threat assessments.
• Mitigation strategies include physical security enhancements (e.g., barriers and surveillance), regular active shooter drills, improved emergency communication systems, and coordinated law enforcement and public health responses. • Investment in resilience-building measures and community outreach helps to ensure that, in the event of an incident, communities can recover quickly and effectively.

This section underscores that while mass violence events are rare, their potential for high impact demands rigorous preparedness and adaptive mitigation strategies to safeguard lives and maintain community functionality.

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6.12 Cybersecurity Incidents

6.12.1 Nature
Cybersecurity incidents refer to
disruptive events affecting digital
networks and systems. These events
involve the unauthorized electronic
or physical access of information
systems that jeopardizes or disrupts
the integrity, confidentiality, or
availability of information . Cyber
incidents can range from minor
targeted data breaches to large ‐
scale ransomware attacks and
distributed denial -of-service (DDoS)
events that compromise critical
infrastructure. Common types of
cybersecurity incidents include, but
are not limited to:
• Data Breaches: The compromise, unauthorized disclosure, or unauthorized acquisition of information.

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• Malware: Malicious hardware, firmware, or software that is intentionally included or inserted in a system for a harmful purpose. • Ransomware: A type of malicious software designed to lock access to a system until a ransom payment is received. Note that ransom payment is not a guarantee that system access will be restored by the threat actor. • Denial of Service (DoS): An attack meant to shut down a machine or network, rendering it inaccessible to its intended users.
• Distributed Denial of Service (DDos): A DoS attack that uses numerous hosts to perform the attack.
• Insider Threats: When an insider (e.g., an employee or vendor) uses their authorized access, wittingly or unwittingly, to do harm to an organization. • Phishing Attacks: The fraudulent practice of sending emails purporting to be from reputable senders in order to induce individuals to reveal information or download malware by clicking on a link.

Key characteristics of a cybersecurity incident include:

Rapid Onset: Impacts to operations can occur suddenly and evolve quickly. • Sophistication: Can be highly sophisticated with state or non -state actors involved.
• Hybrid Attacks: May involve both cyber and physical components due to interdependencies.
• Non-Malicious Incidents: Technological failures that cause similar impacts to cybersecurity incidents may also occur due to non -malicious reasons such as a software or hardware issue.

Understanding the inherent digital nature and complex characteristics of these incidents is critical to developing effective prevention and mitigation strategies.

6.12.2 Location
Unlike traditional hazards that have a physical geographic footprint, cybersecurity incidents are inherently transboundary. However, their effects manifest locally through the disruption of critical services and systems and necessitate regionally coordinated preparedness and response efforts.

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Jurisdictional Relevance:
• Impact local government networks and county infrastructure. • Affect public and private sector systems within Los Angeles County. • Disrupt critical infrastructure such as utilities and cause cascading impacts. • Involve cyber nodes that, while globally distributed, converge on regional networks.

Critical Sectors Impacted:
• Hospitals and healthcare facilities.
• Financial, banking, or payroll systems.
• Transportation providers and systems.
• Utilities such as electricity, gas, and water.
• Emergency response and public safety agencies.

6.12.3 Extent
The extent of cybersecurity incidents is measured not only by the volume of compromised data or financial loss but also by the potential disruption to essential services and critical infrastructure.

Scope of Impacts:
• Rapid spread across interconnected digital systems.
• Potential for cascading failures that disrupt multiple sectors. • Economic losses that may run into millions of dollars.

Measurable Factors:
• Number of systems compromised.
• Downtime of critical infrastructure and services.
• Financial costs from remediation and lost productivity.

The extensive reach of cybersecurity incidents—both in terms of economic impact and service disruption —highlights the need for robust digital defenses , continuity of operations planning, backup systems and redundancies, disaster recovery strategies, and regional cyber response coordination.

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6.12.4 History
Historically, cybersecurity incidents have evolved from isolated breaches to coordinated attacks that leverage global networks. Early cybersecurity incidents focused on data theft and vandalism. More recent attacks have grown increasingly sophisticated and targeted critical infrastructure or use complex ransomware. Cyber threat actors include state -sponsored groups along with non-s tate groups such as criminal enterprises and terrorist organizations. Recent years have seen cybersecurity incidents affecting large corporations, public entities including local governments, and critical infrastructure sectors. Previous major cybersecurity incidents have included:
• 2024 Los Angeles County Superior Court Ransomware Attack: Resulted in the shutdown of nearly every court system, a multi-day closure of the court, and cascading impacts to operations.
• 2024 Hospital Group Attack: A major hospital company experienced an attack that caused IT and phone system outages and disrupted patient care at several Los Angeles County hospitals.
• 2024 Telecommunication Industry Attacks : A series of attacks against telecommunications providers in the United States resulted in compromised customer data.
• 2023 City Attack: A cybersecurity incident at a city within Los Angeles County caused city IT systems to be taken offline.
• 2022 Aviation Industry Attacks: A series of cybersecurity incidents targeting the airports and airlines caused transportation system disruptions.

The historical progression from rudimentary attacks to highly coordinated cybersecurity incidents underscores the growing importance of proactive risk management in the digital realm.

6.12.5 Probability
The probability of cybersecurity incidents occurring is increasing as digital interconnectivity expands and as attackers continue to innovate their methods.

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Risk Trends:
• Rapid expansion of the Internet of Things (IoT), the network of internet - connected devices ranging from smart refrigerators to autonomous vehicles, has added new attack vectors to the threat landscape.
• Increasing sophistication of cybercriminal methods including zero-day exploits, a previously unknown cybersecurity vulnerability.
• Growing frequency of reported incidents nationally and globally.

Contributing Factors:
• Inadequate cybersecurity measures in legacy systems still being used by organizations.
• Underinvestment in cyber defense infrastructure or cybersecurity expertise. • Greater digital reliance in everyday operations without proper continuity of operations planning.

Given current trends and technological developments, the likelihood of cybersecurity incidents remains high, necessitating ongoing vigilance and enhanced preparedness measures. As cybersecurity incidents continue to increase in frequency, the potential for an incident to cause cascading and widespread impacts to critical infrastructure increases as well.

6.12.6 Vulnerability
Vulnerability in the context of cybersecurity refers to the susceptibility of digital systems to attack. This is influenced by both technological and organizational factors including, but not limited to: outdated software or use of legacy systems, insufficient patch management, inadequate segmentation and defense-in -depth strategies, and lack of cybersecurity training among personnel. Organizational challenges also contribu te to cybersecurity vulnerability including, but not limited to: budget constraints, gaps in coordination, and rapid technology adoption without corresponding security protocols.

According to the 2024 Threat and Hazard Identification and Risk Assessment (THIRA), over 616,000 people may be affected by a large -scale cybersecurity incident with cascading impacts to utilities . Over 123,000 of those impacted in the THIRA scenario are estimated to have access and functional needs and over 77,000 people are County of Los Angeles
All-Hazards Mitigation Plan

estimated to have limited English proficiency. Depending on the utilities affected by the incident, a widespread amount of the population could be without utility service for an extended period. Addressing these vulnerabilities is essential to reduce the risk and potential disruption of cybersecurity incidents, calling for both technical upgrades and improved interagency coordination.

6.12.7 Impacts
The impacts of cybersecurity incidents are multifaceted, affecting economic stability, public safety, and critical infrastructure operations.

Direct Impacts:
• Disruption of critical services (e.g., healthcare, emergency response , transportation, etc.).
• Extended duration Continuity of Government or Continuity of Operations event. • Financial losses due to ransom payments, remediation costs, and potential legal fees.
• Loss, compromise, or unauthorized release of sensitive data.

Indirect impacts:
• Erosion of public trust in digital services and affected institutions. • Cascading effects on physical infrastructure (e.g., power grid , water systems, wastewater, etc.).
• Long-term economic repercussions from reduced competitiveness. • The significant impacts—both direct and cascading —of cybersecurity incidents necessitate comprehensive mitigation and recovery strategies that address both technical and socioeconomic dimensions.

6.12.8 Summary
In summary, cybersecurity incidents represent an evolving and critical threat that intersects with multiple aspects of community resilience and safety.

Key Takeaways:
• Cyber incidents are dynamic, sophisticated, and far-reaching in impact • They affect local systems despite their global nature County of Los Angeles
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• Historical trends and increasing digital dependency heighten both probability and vulnerability
• Impacts extend beyond financial loss to include service disruption and cascading infrastructure failures
Cybersecurity incidents demand a proactive, coordinated response that integrates robust technical defenses with cross -sector planning and recovery efforts. By understanding the nature, scope, and potential consequences of these incidents, communities can build more resilient digital and physical infrastructures to safeguard against this growing threat.

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6.13 Transportation Incidents

6.13.1 Nature
This section describes the inherent characteristics of transportation incidents that can disrupt the continuous flow of people, goods, and emergency services across Los Angeles County. Transportation incidents can be triggered by a variety of factors including natural events, human error, and deliberate acts. Other characteristics include:
• Affected Modes of Transportation: Incidents can involve any mode of transportation such as multi -vehicle collisions, hazardous material spills, rail derailments, aviation incidents, and maritime disruptions. • Cascading Impacts: Disruptions to the transportation system o ften have the potential to trigger cascading failures due to the interconnected design of highways, rail networks, airports, and seaports.
• Contributing Factors: Incidents may be influenced by both predictable factors (e.g., rush-hour congestion) and unpredictable occurrences (e.g., extreme weather or infrastructure failure).

6.13.2 Location
The county’s network encompasses highways, rail, airports, ports, and local roads that are critical to regional mobility and commerce.

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• Freeways: Los Angeles County boasts an extensive freeway system with over 1,200 miles of high -capacity roads including corridors such as I- 5, I-405, I-10, I-710, and I-210.
• Major Transportation Hubs: The County is home to three commercial airports including Los Angeles International Airport (LAX), Long Beach Municipal Airport (LGB), and the Hollywood Burbank Airport (BUR) along with several general aviation airports. The County owns and operates Brackett Field Airport, Compton/Woodley Airport, San Gabriel Valley Airport, General William J. Fox Airfield, and Whiteman Airport. The Ports of Los Angeles and Long Beach, which are two of the busiest ports in the United States and v ital for national and international trade, are also in Los Angeles County. Additionally, Los Angeles Union Station serves as the largest passenger rail station on the west coast. • Other Transportation Networks: The county includes robust passenger rail, bus, and paratransit systems, along with freight rail systems, emerging mobility options such as taxis and rideshare services, and enhanced bicycle networks .

This comprehensive network is the backbone for daily commuting, freight movement, and emergency response across the region.

6.13.3 Extent
The scope of transportation incidents spans multiple modes of travel and can have widespread consequences across the county’s integrated infrastructure. Road incidents may include multi -vehicle collisions, hazardous material spills, and roadway fires impacting multiple vehicles with potential delays in emergency responses. • Rail disruptions can impede commuter and freight services, impacting both local transit and regional connectivity.
• Air and maritime incidents—such as delays at major airports or disruptions at port facilities—can significantly affect commerce, supply chains, and public safety. • Cascading effects across interconnected transportation modes may exacerbate congestion and strain additional infrastructure systems such as power, water, and emergency communications.

The extensive and interdependent nature of these networks means that an incident in one area can quickly influence multiple transportation systems.

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6.13.4 History
Los Angeles County has a long record of transportation-related incidents that have disrupted mobility and commerce.
• 2024 Vincent Thomas Bridge Fire: A semi-truck carrying lithium-ion batteries overturned and caught fire, causing the bridge to be closed for several days. • 2023 I -10 Freeway Fire: A fi r e i n a p a l l e t y a r d b e l o w t h e I-10 freeway in Downtown Los Angeles caused an eight -day closure for repairs and major cascading disruptions.
• 2020 Delta Air Lines Flight 89 Fuel Drop: S h o r t l y a f t e r t a k e o f f f r o m L A X , a Boeing 777 encountered engine problems and conducted a fuel dump over populated areas, injuring over 50 people on the ground. • 2008 Chatsworth Metrolink Derailment: A Metrolink passenger train collided with a Union Pacific freight train injuring over 130 people and causing 25 deaths. • 2007 Newhall Pass Tunnel Fire: A multi -vehicle collision involving over 30 vehicles caused a fire within the tunnel injuring 10 people and causing 3 deaths.

The historical record reinforces the need to learn from previous events to enhance future preparedness and resilience.

6.13.5 Probability
The likelihood of transportation incidents in Los Angeles County remains elevated due to several converging factors including, but not limited to:
• High daily traffic volumes on freeways and arterials increase the risk of multi - vehicle accidents and congestion-related incidents.
• Aging infrastructure—including bridges, road surfaces, and rail systems—creates a persistent risk of failure, particularly under extreme weather conditions and during peak usage periods.
• The county’s role as a major hub for freight and commuter traffic means that even minor incidents can escalate rapidly into larger disruptions. • The frequent movement of hazardous materials and the increasing reliance on just-in-time delivery systems further elevate the risk of incidents with potentially severe consequences.

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Together, these factors contribute to a consistently high probability of transportation incidents impacting the region.

6.13.6 Vulnerability
The vulnerability of Los Angeles County’s transportation system is compounded by its interdependent design and its critical role in the regional economy. • Limited redundancy in key corridors means that a disruption on one freeway or rail line can quickly overload alternate routes.
• Aging and overburdened infrastructure is less resilient to extreme events, leading to longer recovery times after incidents.
• The county’s economic dependence on uninterrupted transportation for daily commuting and commercial freight increases exposure to significant losses during disruptions.
• Complex interdependencies between transportation systems, emergency services, and other critical sectors make the network highly sensitive to cascading failures.

This systemic vulnerability calls for coordinated, multi-agency efforts to bolster resilience and implement proactive mitigation measures.

6.13.7 Impacts
Transportation incidents can produce both immediate and long -lasting effects on public safety, commerce, and overall quality of life.

1. Traffic and Mobility: Disruptions can lead to severe congestion affecting hundreds of thousands of commuters and freight vehicles, delaying emergency services and disrupting daily operations.

2. Economic Loss: Interruptions in the movement of goods and people can result in substantial financial losses, impacting local businesses and the broader regional economy.

3. Public Safety: Extended delays in emergency response and Emergency Medical Services (EMS) transport times.

4. Cascading Disruptions: An incident in one mode (e.g., a major highway closure) can ripple through the transportation network, affecting rail, air, and maritime operations simultaneously and complicating recovery efforts.

These impacts highlight the critical need for robust mitigation strategies to manage both direct and indirect consequences of transportation incidents.

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6.13.8 Summary
Los Angeles County’s transportation network is among the most extensive and complex in the nation, serving millions of residents and underpinning a vital economic ecosystem. The diverse transportation modes, while facilitating mobility and commerce, also create vulnerabilities due to overlapping infrastructure and high traffic volumes.
• Aging infrastructure, coupled with the continuous movement of hazardous materials and the increasing pressures of daily usage, contributes to a high probability of incidents.
• Historical data demonstrate that even localized incidents can have far -reaching impacts, including prolonged traffic congestion, economic disruptions, and public safety challenges.

In conclusion, mitigating transportation incident risks in Los Angeles County requires an integrated, countywide approach that combines infrastructure upgrades, enhanced emergency response, and proactive maintenance strategies. Addressing these challenges is essential to safeguard public safety, ensure economic stability, and maintain the region’s critical mobility infrastructure.

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6.14 Public Health Emergencies

6.14.1 Nature
Public health emergencies in Los
Angeles County encompass a broad
spectrum of potential hazards,
including infectious disease
outbreaks, environmental health
hazards, and Chemical, Biological,
Radiological, Nuclear, Explosives
(CBRNE) hazards. Given the county's
diverse population, urban density,
and economic significance, public
health hazards require a coordinated
response among government
agencies, healthcare institutions, and
community partners.

Public health emergencies refer to
incidents that pose a significant
threat to the health of a population.

These include, but are not limited to:
• Pandemics (e.g., COVID-19, Influenza)
• Bioterrorism (e.g., Anthrax, Smallpox, botulism)

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• Vector-borne diseases (e.g., West Nile Virus, Zika)
• Foodborne and waterborne illnesses
• Chemical and radiological exposure
• Climate-related health threats (e.g., extreme heat, poor air quality, wildfires) The County of Los Angeles Department of Public Health (DPH) and the Emergency Medical Services Agency (EMS) collaborate to monitor threats, prevent outbreaks, and mitigate impacts when emergencies arise.

6.14.2 Location and Extent
Los Angeles County, home to over 9.7 million residents, is the most populous count y in the United States. Its diverse geography (i.e., urban, coastal, mountainous, and rural) and demography lead to a range of public health vulnerabilities.

Public health emergencies can originate from local, regional, national, or global sources, impacting specific neighborhoods or the entire county. The extent of public health threats varies based on:
• The nature of the threat, such as transmission dynamics or availability of medical countermeasures.
• Population density (higher risks in urban centers for communicable diseases) • Access to healthcare infrastructure
• Environmental conditions (air pollution, extreme heat events)

6.14.3 History
Public health emergencies in Los Angeles County have included:
• 2022 Monkeypox Outbreak
o Approximately 2,500 cases were reported in Los Angeles County. • COVID-19 Pandemic (2020–Present)
o Over 3 million cases, 450,000 hospitalizations, and 45,000 deaths reported in the county alone.
• 2018 Hepatitis A Outbreak
o Primarily affecting unhoused populations, requiring mass vaccination efforts.
• 2016-2017 West Nile Virus Outbreaks
o Multiple cases of mosquito-borne infections leading to severe illness and fatalities.

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• 2015-2016 Zika Virus Outbreak
o No cases of local mosquito-borne transmission, but there were 122 cases reported in the County, with 121 being travel-related.
• 2015 Meningococcal Disease Cluster
o An outbreak among men who have sex with men (MSM) led to a targeted vaccination campaign.
• 2009 H1N1 Influenza Pandemic
o Thousands of hospitalizations; schools and businesses affected.

6.14.4 Probability and Emerging Risks
The 2024 Threat and Hazard Identification and Risk Assessment (THIRA) identifies that pandemics and bioterrorism remain high-probability threats. Future public health risks also include:
• Emergence of infectious diseases driven by global travel and climate change. • Increased incidence of heat-related illnesses amid rising temperatures. • Increased prevalence of respiratory diseases due to declining air quality. • Rise of antimicrobial-resistant infections due to overuse of antibiotics.

The County of Los Angeles DPH continually assesses health threats and updates preparedness plans to address evolving concerns.

6.14.5 Vulnerability and Systemic Impacts
Certain populations in Los Angeles County may be disproportionately affected by public health emergencies:
• At-risk populations may be different for different hazards before, during, and after an emergency. It is important to assess each hazard in turn to identify those who may be disproportionately affected to improve preparedness and response efforts.

Public health emergencies strain the healthcare system, disrupt economic activity, and create mental health burdens. The 2024 THIRA report noted that:
• Healthcare infrastructure overload is a major concern during pandemics. • Potential economic loss from business closures during a prolonged public health crisis could exceed billions of dollars.

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6.14.6 Mitigation Strategies and Preparedness Efforts
Los Angeles County employs several mitigation and preparedness strategies:
• Mass Vaccination Campaigns
o Annual flu shots, COVID -19 vaccinations, and outbreak -specific immunization efforts.
• Points-of-Dispensing (POD) sites
o Disease Surveillance & Early Warning Systems
• Syndromic surveillance for emerging threats.
o Targeted sampling surveillance.
• Healthcare Infrastructure Strengthening
o Expanding hospital capacity for medical surge, and emergency medical resources.
• Community Outreach & Public Health Education
o Disseminating critical information in multiple languages. • Emergency Stockpiles (Strategic National Stockpile(SNS)) o Deployment of antibiotics, antivirals, and personal protective equipment (PPE) in crisis situations.
• Coordination with Federal & State Agencies
o Collaboration with FEMA, CDC, and the California Department of Public Health to enhance response capabilities.
• Anthrax Threat Simulations
o The County of Los Angeles Metro system assessed as a high-risk area for bioterrorism response.

6.14.7 Summary
Public health emergencies pose significant challenges to Los Angeles County , impacting healthcare systems, vulnerable populations, and economic stability. While the COVID-19 pandemic provided a major stress test for response efforts, ongoing preparedness, surveillance, and mitigation strategies aim to protect residents from future threats.

Key Takeaways:
• Los Angeles County faces diverse health threats, including pandemics, bioterrorism, and climate-related illnesses.

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• Vulnerable populations may suffer disproportionate impacts during public health crises.
• Preparedness efforts focus on surveillance, vaccination, emergency response, and coordination with federal and state partners.
• Future threats include emerging infectious diseases, heat-related illnesses, and antimicrobial resistance.

By continuing investments in public health preparedness, Los Angeles County aims to reduce risks and strengthen resilience against future health emergencies.

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7 Mitigation Strategy
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All-Hazards Mitigation Plan

7.1 Mitigation Strategy Overview
The Mitigation Strategy section of the All-Hazard Mitigation Plan (AHMP) presents Los Angeles County’s strategic blueprint for reducing risks and vulnerabilities posed over the long term associated with the hazards identified in the Hazard Identification a nd Risk Assessment section. The strategies identified in this section drive mitigation activities based on existing capabilities while also identifying areas of potential future investment to build resilience across communities, critical facilities, and ot her infrastructure within Los Angeles County.

7.2 Mitigation Goals and Objectives
Mitigation goals are the long-term vision that the County hopes to achieve by implementing the various mitigation strategies described in this AHMP , as well as the broad guidelines that have shaped mitigation strategy development. • Goal 1: Protect life, property, infrastructure, the environment, and the economy through equitable mitigation strategies aimed at reducing risks of natural and human-caused hazards.
o Objective 1-1: Integrate vulnerable populations, including people with Access and Functional Needs (AFN), into the implementation of any potential mitigation actions.
o Objective 1-2: Implement mitigation strategies that enhance resilience to disaster impacts across residential areas, commercial areas, infrastructure, high-hazard potential dams, and other critical facilities. o Objective 1-3: Inform strategic investments in climate adaptation, development, and redevelopment that are centered in equity and resilience.
• Goal 2: Enhance community-wide partnerships in hazard mitigation across all levels of government, the private sector, and the public. o Objective 2-1: Build a culture of disaster resilience and awareness of local hazards through public engagement, education, and outreach. o Objective 2-2: Strengthen direct coordination among Los Angeles County Operational Area partners to unify efforts for mitigation activities. o Objective 2-3: Utilize a whole community approach to address disparities in outcomes posed by the hazards identified in this AHMP . • Goal 3: Enhance planning, response, and recovery through hazard identification, assessment, mitigation, and resilience activities.

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o Objective 3-1: Establish and maintain coordination between hazard mitigation activities and other emergency management functions. o Objective 3-2: Integrate hazard mitigation activities into preparedness for future large-scale planned events within Los Angeles County. • Goal 4: Ensure eligibility for FEMA grant funding to maximize equitable investment in hazard mitigation actions.
o Objective 4-1: Continue to meet all requirements for existing hazard mitigation grant programs used by the County.
o Objective 4-2: Expand the County’s ability to participate in grant programs not currently utilized by the County.

7.2.1 Changes in Mitigation Goals
The AHMP Advisory Committee reviewed the 2020 AHMP goals and updated them to reflect the most current County concerns and priorities. Therefore, the 2025 AHMP has introduced new goals and objectives to build a more resilient community. Table 7 -1 (below) compares the 2025 AHMP goals with previous 2020 AHMP goals; all other goals above are new goals and objectives developed by the AHMP Advisory Committee.

Mitigation priorities change through time depending on the type of disaster impacting Los Angeles County, vulnerability, the strategies implemented, as well as other needs of the community. Priorities are also made based on current countywide Threat and Hazard Identification and Risk Assessment (THIRA) studies, National Risk Index Assessment, State Hazard Mitigation Plan (SHMP) and other local plans and guides. The previous 2020 AHMP integrated hazard data into several operational plans including but not li mited to the General Plan, Operational Area Emergency Operations Plan (OAEOP), amongst others. Addressing these changes will help to address Los Angeles County hazard priorities and to have mitigation strategies focused on the hazards that impact the region at most. The plan also added additional hazards and addressed a larger vulnerable population.

Table 7-1 Mitigation Goal Updates
Goals Addressed in
2020 AHMP
Goals for 2025-2030
Planning Period
Changes
Build a culture and
practice disaster
resilience
Goal 2 (see above). Goal expanded;
previous goal
integrated as an
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All-Hazards Mitigation Plan

Goals Addressed in
2020 AHMP
Goals for 2025-2030
Planning Period
Changes
objective under Goal 2
in the current AHMP .

Better plan for, respond
to, and recover from,
hazards and disasters
including climate change,
drought, earthquake,
dam failure, flood,
landslide, tsunami, and
wildfire that affect Los
Angeles County.

Goal 3 (see above). Previous goal replaced
with new goal.

More successfully adapt
to hazards and disasters
including climate change,
drought, earthquake,
dam failure, flood,
landslide, tsunami, and
wildfire that affect Los
Angeles County.

Goal 1 (see above). Previous goal replaced
with new goal.

7.3 Existing Mitigation Capabilities
The mitigation strategies developed as part of this AHMP seek to maximize existing mitigation capabilities identified as currently available within the Los Angeles County Operational Area. These existing capabilities have been updated to reflect changes in human, technical, financial, legal, regulatory, education, and outreach resources since the 2020 AHMP .

County of Los Angeles
All-Hazards Mitigation Plan

7.3.1 Authorities, Policies, and Legal/Regulatory Resources There are several existing authorities, policies, and other legal or regulatory resources applicable to hazard mitigation efforts in Los Angeles County. From the County Code of Ordinances to completed plans, these form the cornerstone of hazard mitigation activities by pro viding a foundation rooted in data, research, planning, Technical Ecological Knowledge (TEK) provided by our state and locally recognized indigenous communities, and elected officials’ authority. The County aims to expand and improve upon these identified capabilities by adopting this AHMP , once approved, into the Safety Element of the Los Angeles County General Plan. This action will contribute to the County’s ability to be considered for an additional cost-share on Public Assistance projects through the California Disaster Assistance Act. Table 7-2 provides an overview of existing capabilities related to authorities, policies, and legal/regulatory resources.

Table 7-2 Authorities, Policies, and Legal/Regulatory Resources Authority,
Policy, or
Resource
Description Hazards
Addressed
Potential to
Affect
Development
Los Angeles
County
Operational
Area
Emergency
Operations
Plan (2023)
Establishes the coordinated
emergency management system
within the Los Angeles County
Operational Area to prepare for,
respond to, and recover from the
effects of large-scale emergencies
regardless of cause, location, or
complexity.

All-Hazard No
Los Angeles
County General
Plan (2024)
Provides the policy framework for
how and where the
unincorporated County will grow
through the year 2035.

All-Hazard Yes
Los Angeles
County
Comprehensive
Floodplain
Reviews existing floodplain
management programs in the
County and recommends
enhancements to them through 35
Flood
Land
Movement
Yes
County of Los Angeles
All-Hazards Mitigation Plan

Authority,
Policy, or
Resource
Description Hazards
Addressed
Potential to
Affect
Development
Management
Plan (2021)
mitigation actions. This plan is
currently being reviewed and
updated with completion targeted
for early 2026.

Los Angeles
County
Comprehensive
Floodplain
Management
Plan Repetitive
Loss Area
Analysis (2021)
Analyzes Repetitive Los Areas
within Los Angeles County and
fulfills Community Rating System
requirements.

Flood
Land
Movement
Yes
County of Los
Angeles
Floodplain
Management
Plan Progress
Report (2024)
Provides an annual update on the
implementation of the action plan
identified in the Comprehensive
Floodplain Management Plan and
on the implementation and
evaluation of outreach projects.

Flood
Land
Movement
Yes
County of Los
Angeles
Repetitive Loss
Area Analysis
Progress Report
(2023)
Provide an annual update on the
implementation of the action plan
identified in the Repetitive Loss
Area Analysis to ensure there is a
continuing and responsive
planning process.

Flood Yes
Los Angeles
County Fire
Plan (2023)
Describes the wildfire
environment, history, and pre-fire
management strategies to
enhance the protection of lives,
property, and natural resources
from wildland fire.

Wildfire Yes
County of Los Angeles
All-Hazards Mitigation Plan

Authority,
Policy, or
Resource
Description Hazards
Addressed
Potential to
Affect
Development
Los Angeles
County 2045
Climate Action
Plan (2024)
Delineates the County’s path
toward
meeting the goals of the Paris
Agreement and achieving carbon
neutrality for unincorporated
Los Angeles County.

Wildfire
Extreme
Heat
Drought
Flooding
Yes
Our County:

Los Angeles
Countywide
Sustainability
Plan (2019)
Outlines how local governments
and stakeholders can enhance the
well-being of all County
communities while adapting to
climate change and reducing
damage to the natural
environment, particularly focusing
on communities disproportionately
burdened by pollution.

Wildfire
Extreme
Heat
Drought
Flooding
Yes
Los Angeles
County
Floodplain
Management
Ordinance
Aims to minimize public and
private losses resulting from flood
conditions via uniformly applied
regulations in flood prone,
mudflow, or flood related erosion
areas.

Flood
Land
Movement
Yes
Los Angeles
County Code –
Title 32: Fire
Code
To build a new structure (or an
addition equal to or greater than
50% of existing square footage),
the Los Angeles County Fire Code
requires review of its location, type
of construction, topography, slope,
amount and arrangement of
vegetation, and overall site
Wildfire Yes
County of Los Angeles
All-Hazards Mitigation Plan

Authority,
Policy, or
Resource
Description Hazards
Addressed
Potential to
Affect
Development
settings—in order to create
defensible space necessary for
effective fire protection of homes
in High Fire Severity Zones.

Los Angeles
County Code –
Title 22:

Planning and
Zoning
Establishes the regulations
governing land use and
development and defines zoning
for unincorporated Los Angeles
County. Includes the Hillside
Management Area Ordinance
(Chapter 22.104), the Residential
Design Standards Ordinance, and
the Hillside Design Guidelines.

These include requirements for
development in Hillside
Management Areas, which are
defined as areas with 25% or
greater natural slopes. The
guidelines include specific and
measurable design techniques that
can be applied to residential,
commercial, industrial, and other
types of projects.

Wildfire
Earthquake
Land
Movement
Yes
Los Angeles
County Code –
Title 31: Green
Building
Standards
Code
Enhances the design and
construction of buildings via
building concepts with positive (or
reduced negative) environmental
impacts, and encourages
sustainable construction practices
Extreme
Heat
Drought

Yes
County of Los Angeles
All-Hazards Mitigation Plan

Authority,
Policy, or
Resource
Description Hazards
Addressed
Potential to
Affect
Development
across planning and design,
energy efficiency, water
conservation, material and
resource efficiency, and
environmental air quality.

Los Angeles
County Brush
Clearance
Program
Legally declares both improved
and unimproved properties a
public nuisance, and where
necessary, requires the clearance
of hazardous vegetation thereby
creating defensible space for
effective fire protection of
property, life, and the environment.

The Brush Clearance Program is a
joint effort between the County of
Los Angeles Fire Department and
the County of Los Angeles
Department of Agricultural
Commissioner/Weights and
Measures, Weed Hazard, and Pest
Abatement Bureau (Weed
Abatement Division).

Wildfire Yes
Los Angeles
County Code –
Title 26:

Building Code
Provides minimum standards to
regulate the design, construction,
installation, quality of materials,
use, occupancy, location, and
maintenance of all buildings,
structures, grading, and certain
equipment. Regulates construction
Earthquake
Wildfire

Yes
County of Los Angeles
All-Hazards Mitigation Plan

Authority,
Policy, or
Resource
Description Hazards
Addressed
Potential to
Affect
Development
near a known active earthquake
fault (Chapter 1, Section 113), the
materials and construction
methods for construction in a
Wildland-Urban Interface (WUI)
Fire Area (Chapter 7A), structural
design as it relates to earthquake
hazards (Chapter 16, Section
1613), repair of certain buildings in
High Earthquake Damage Areas
(Chapter 94), earthquake hazard
reduction for concrete tilt-up
buildings (Chapter 95) and
unreinforced masonry buildings
(Chapter 96), among others. The
Building Code also includes
provisions for emergency housing
during a proclaimed emergency.

7.3.2 Human and Technical Resources
Existing human and technical resources across County Departments enable the County to plan, manage, conduct, and execute its wide range of hazard mitigation activities. The resources below represent a high degree of expertise in all facets of hazard mitigation available to support mitigation activities. The County aims to expand and improve upon these identified capabilities by expanding potential hazard training opportunities available to the Los Angeles County Operational Area.

Additionally, as various special events are scheduled in Los Angeles County over the next five years, the County should seek to expand coordination and technical resources related to mass violence, cyber, and other special event-related hazards.

County of Los Angeles
All-Hazards Mitigation Plan

Table 7-3 provides an overview of existing capabilities related to human and technical resources.

Table 7-3 Human and Technical Resources
Resource Department/Agency Principal Activities Related to Hazard Mitigation
Emergency
Management
Coordinator(s)
Los Angeles County
Office of Emergency
Management
• Maintains and updates the Los
Angeles County Operational Area
Emergency Operations Plan and Los
Angeles County All-Hazard
Mitigation Plan.
• Coordinates local response and
recovery activities in the Emergency
Operation Center and in the field.
• Works closely with local, state, and
federal partners to support planning,
training, exercise, public information,
and resource coordination.

Engineer(s),
Building
Inspector(s),
Code
Enforcement
Officer(s), Fire
Marshalls, and
Other Technical
Staff
Los Angeles County
Public Works and Fire
Department
• Oversees the effective, efficient, fair,
and safe enforcement of County of
Los Angeles Building and Fire
Codes.

Engineer(s),
Construction
Project
Managers, and
Other Technical
Staff
Los Angeles County
Public Works
• Provides direct (or contract) civil,
structural, and mechanical
engineering services, including
contract, project, and construction
management.

Engineer(s),
Project
Los Angeles County
Public Works
• Maintains and operates a wide range
of local equipment and facilities and
assists members of the public by
County of Los Angeles
All-Hazards Mitigation Plan

Resource Department/Agency Principal Activities Related to Hazard Mitigation
Manager(s),
Equipment
Operators,
Maintenance and
Construction
Staff, and Other
Technical Staff
providing sufficient clean fresh water,
reliable sewer services, street
maintenance, storm drainage
systems, street cleaning, streetlights,
and traffic signals.

Floodplain
Administrator
Los Angeles County
Public Works
• Enforces the floodplain management
ordinance ensuring that
development proposals do not
increase flood risk and that new
developments are not located below
the 100-year flood level. In addition,
the floodplain administrator is
responsible for planning and
managing flood risk reduction
projects throughout Los Angeles
County.

Planner(s),
Engineer(s), and
Technical Staff
Los Angeles County
Department of
Regional Planning
• Develops and maintains the Los
Angeles County General Plan,
including the Safety Element.
• Develops area plans based on the
Los Angeles County General Plan to
provide more specific guidance for
the development of more specific
areas.
• Reviews proposed development,
capital improvements, and other
physical projects involving property
for consistency and conformity with
the Los Angeles County General
Plan.
• Anticipates and acts on the need for
applicable new plans, policies, and
code changes.

County of Los Angeles
All-Hazards Mitigation Plan

Resource Department/Agency Principal Activities Related to Hazard Mitigation
• Applies the approved plans, policies,
code provisions, and other
regulations to proposed land uses.

Procurement
Services
Manager
Los Angeles County
Internal Services
Department
• Provides a full range of municipal
financial services and administers
several licensing measures.

Comptroller
Personnel
Los Angeles County
Auditor – Controller
• Provides financial and grant services.

County Counsel
Personnel
Los Angeles County
Counsel
• Provides legal services for the
County.

Fire Department
Personnel
Los Angeles County
Fire Department
• Provides fire protection services
including response, fire prevention,
and mitigation activities for the
County.

Sheriff’s
Department
Personnel
Los Angeles County
Sheriff’s Department
• Provides law enforcement services in
the County.

7.3.3 Financial Resources and Programs
There are many existing financial resources, grant programs, and other funding mechanisms that enable current and future hazard mitigation activities. Sources for these resources and programs vary widely from local funding out of the County’s General Fund to state and federal programs that aim to help local jurisdictions accomplish their hazard mitigation goals. The amount of funding available is variable and project-specific for many of these programs. Similarly, grant awards are based on the specific projects that are identified as the basis for the grant application. Table 7-4 provides an overview of existing capabilities related to financial resources and programs.

County of Los Angeles
All-Hazards Mitigation Plan

Table 7-4 Financial Resources and Programs
Resource or
Program Administrator Purpose
General Fund
Chief
Executive
Office
Program operations and specific projects.

General
Obligation Bonds
Auditor -
Controller
General obligation bonds are appropriately
used for the construction and/or acquisition of
improvements to real property broadly
available to residents and visitors. Such facilities
include but are not limited to: libraries,
hospitals, parks, public safety facilities, and
cultural and educational facilities.

Special Tax and
Revenue Bonds Controller
Revenue bonds are used to finance capital
projects that:

1. Have an identified budgetary stream for
repayment (e.g., specified fees, tax
receipts);

2. Generate project revenue but rely on a
broader pledge of general fund revenues to
reduce borrowing costs; or

3. Finance the acquisition and installation of
equipment for the local jurisdiction’s
general governmental purposes.

Vegetation
Management
Program
Cal FIRE
Cost-sharing program between Cal FIRE and
private landowners, which focuses on the use of
prescribed fire and/or mechanical means, for
addressing wildland fire fuel hazards and other
resource management issues on State
Responsibility Area (SRA) lands.

Wildfire
Emergency and
Mitigation Funds
Cal FIRE Administers funding from FEMA, Bureau of
Land Management, and U.S. Forest Service for
County of Los Angeles
All-Hazards Mitigation Plan

Resource or
Program Administrator Purpose
certain types of wildfire emergency and
mitigation funding.

California
Residential
Mitigation
Program
California
Earthquake
Authority
Created by the California Earthquake Authority
and the Governor’s Office of Emergency
Services, “Earthquake Brace + Bolt: Funds to
Strengthen Your Foundation” is the first
incentive program offered by the California
Residential Mitigation Program.

Public Health
Emergency
Preparedness
Cooperative
Agreement
Center for
Disease
Control and
Prevention
Funds are intended to upgrade state and local
public health jurisdictions’ preparedness and
response to bioterrorism, outbreaks of
infectious diseases, and other public health
threats and emergencies.

Hazard Mitigation
Grant Program
(HMGP)
FEMA
Administered by the California Governor’s
Office of Emergency Services (Cal OES), HMGP
supports pre- and post-disaster mitigation
plans and projects available to California
communities after a presidentially declared
disaster has occurred in California.

Pre-Disaster
Mitigation (PDM)
Grant Program
FEMA
Available annually as a nationally competitive
Cal OES grant, the PDM Grant Program
supports pre-disaster mitigation plans and
projects.

Flood Mitigation
Assistance (FMA)
Grant Program
FEMA
Available annually as a nationally competitive
Cal OES grant, the PDM Grant Program
supports pre-disaster mitigation plans and
projects.

Homeland
Security FEMA Builds and sustains preparedness technical assistance activities in support of the four
County of Los Angeles
All-Hazards Mitigation Plan

Resource or
Program Administrator Purpose
Preparedness
Technical
Assistance
Program
homeland security mission areas (i.e.,
prevention, protection, response, recovery) and
homeland security program management.

Assistance to
Firefighters Grant
Program
FEMA/U.S.

Fire
Administration
Provides equipment, protective gear,
emergency vehicles, training, and other
resources needed to protect the public and
emergency personnel from fire and related
hazards. Available to fire departments and
nonaffiliated emergency medical services
providers.

Land and Water
Conservation
Funds
U.S.

Department of
the Interior
Supports the protection of federal public lands
and waters and voluntary conservation on
private land.

Community
Action for a
Renewed
Environment
U.S.

Environmental
Protection
Agency (EPA)
Offers means by which communities may
organize/take action to reduce toxic pollution
(e.g., in stormwater, etc.) through financial and
technical assistance. Communities create
partnerships that implement solutions to
reduce releases of toxic pollutants and that
minimize toxic exposures.

Clean Water
State Revolving
Fund
EPA
A loan program that provides low-cost
financing to eligible entities on state and tribal
lands for water quality projects, including all
types of non-point source, watershed
protection or restoration, estuary management
projects, and more traditional municipal
wastewater treatment projects.

County of Los Angeles
All-Hazards Mitigation Plan

Resource or
Program Administrator Purpose
Community Block
Grant Program
Entitlement
Communities
Grants
U.S.

Department of
Housing and
Urban
Development
Acquisition of real property, relocation and
demolition, rehabilitation of residential and
non-residential structures, construction of
public facilities and improvements (e.g.,
water/sewer facilities, streets, neighborhood
centers, etc.), and the conversion of school
buildings for eligible purposes.

High Hazard
Potential Dams
(HHPD) Grant
Program
FEMA
Provides technical, planning, design, and
construction assistance in the form of grants for
the rehabilitation of eligible high hazard
potential dams.

State and Local
Cybersecurity
Grant Program
FEMA
Provides funding to eligible entities to address
cybersecurity risks and threats to information
systems owned or operated by, or on behalf of,
state, local, or tribal governments.

7.3.4 Education and Outreach Resources
Engagement with the communities of Los Angeles County is an important component of mitigation efforts. The County of Los Angeles has multiple methods, formats, and venues to conduct outreach with community members and provide education on the hazard landscape in Los Angeles County. These activities ensure mitigation efforts align with community goals and include community input. Table 7 -5 shows a list of existing resources for education and outreach.

Table 7-5 Education and Outreach Resources
Resource or
Program
Agencies Potentially
Involved Purpose
Preparedness
Fairs
Office of Emergency
Management, Fire
Engage with community
members to provide education
County of Los Angeles
All-Hazards Mitigation Plan

Resource or
Program
Agencies Potentially
Involved Purpose
Department, Sheriff’s
Department, Public Works,
Board of Supervisors
on hazards found in Los
Angeles County and
emergency preparedness for
homes and businesses.

Personal Disaster
Impact Surveys
Office of Emergency
Management
Receive input and feedback on
the hazard landscape from
community members in Los
Angeles County to inform the
2025 AHMP .

AHMP Draft
Review Surveys
Office of Emergency
Management
Receive input and feedback on
sections of the AHMP from
community members in Los
Angeles County.

Homeless
Outreach
Services Team
(HOST)
Sheriff’s Department,
Homelessness Services
Organizations
Conduct outreach to People
Experiencing Homelessness in
areas prone to wildfires or
flooding based on weather
conditions.

Community
Emergency
Response Teams
(CERT)
Fire Department
Educate community members
about disaster preparedness
and response in their
communities.

Explorer
Programs
Fire Department, Sheriff’s
Department
Educate youth about disaster
preparedness and response in
their communities.

Youth Climate
Commission Chief Sustainability Office
Educate and obtain input from
youth on climate change
impacts and mitigation efforts.

County of Los Angeles
All-Hazards Mitigation Plan

7.3.5 National Flood Insurance Program Participation
The National Flood Insurance Program (NFIP) is administered by FEMA and provides affordable flood insurance to participating communities through a network of insurance providers. NFIP regulations must be enforced in Special Flood Hazard Areas (SFHAs). Flood insurance is required for structures in SFHAs with federally backed loans (e.g., most mortgages, Small Business Administration (SBA) loans) and FEMA grants along with any structures with SBA loans, regardless of flood zone. Flood insurance is required to be maintained for the life of the federally backed loan and in perpetuity, regardless of change in ownership, in the case of FEMA grants.

The Los Angeles County Board of Supervisors adopted the County Floodway Ordinance (Los Angeles County Code Title 11, Chapter 11.60) in March 1980. This ordinance included the first County Floodway Maps and paved the way for the County to begin participatio n in NFIP on behalf of unincorporated residents. The County’s participation means that residents (owners and renters) in the unincorporated communities within Los Angeles County are eligible for NFIP flood insurance and Federal flood disaster assistance. T he first FEMA Flood Insurance Rate Maps (FIRMs) became effective on December 2, 1980. Since 1980, the County has continued robust participation in NFIP . The FEMA FIRMs were digitized in September 2008 and have been revised over the years by numerous Letter s of Map Change and by large -scale Physical Map Revisions for the Ballona Creek watershed and several watersheds in the Santa Monica Mountains (Triunfo Creek, Topanga Canyon and others) in December 2018, the Los Angeles County coastline in April 2021, and the Santa Clara River watershed in June 2021. These maps are available to the public on the Los Angeles County Public Works (PW) website at dpw.lacounty.gov/floodzone.

Los Angeles County also participates in the NFIP’s Community Rating System (CRS) program. The CRS program is a voluntary program for communities that engage in community floodplain management activities, which exceed the minimum NFIP standards. CRS communi ties benefit from a discount on flood insurance rates and improved floodplain management programs. CRS uses a class rating system between 1 and 9 to determine flood insurance premium reductions for residents. As of April 1, 2022, Los Angeles County is a Cl ass 6 CRS community; therefore homeowners and County of Los Angeles
All-Hazards Mitigation Plan

renters who live in a SFHA can receive up to a 20% discount on their flood insurance policies.

The County’s implementation and enforcement of local floodplain management regulations for development in SFHAs are covered in Los Angeles County Building Codes with the most recent update completed in 2023. Title 26, Chapter 1, includes requirements for d evelopment within flood hazard areas. Other relevant ordinances include other chapters in Title 26 (Building Code) along with Titles 27 (Electrical Code), Title 28 (Plumbing Code), Title 29 (Mechanical Code), Title 30 (Residential Code), and Title 33 (Existing Building Code). Implementation and enforcement are also covered in the Los Angeles County Subdivision Code (Title 21) and Planning and Zoning Code (Title 22). The NFIP for unincorporated communities is administered by the Department of Public Works (LACPW) Stormwater Engineering Division, which serves as the County’s floodplain manager, coordinates with LACPW’s Building and Safety and Land Development Divisions and with the Los Angeles County Department of Regional Planning in their enforcement of the County’s floodplain management regulations, and participates in FEMA’s Community Assisted Visits, which typically occur on a 5-year cycle.

LACPW continues to enforce NFIP regulations for building permit applications determined by Building and Safety officials to be substantial improvement or repair of substantial damage. Los Angeles County also requires all residential buildings undertaking substantial improvement to have their lowest floor elevated 1 foot above the 100-year flood elevation. Additionally, Los Angeles County conducted a Repetitive Loss Area Analysis in 2020, which serves as a specific plan for reducing damage from flooding in repetitive loss areas.

After an event, Public Works staff assess the unincorporated area buildings within the extent of the event. The assessment will identify the buildings that appear to have damages affecting 50 percent or greater of the building. If such a building is in flood- prone areas identified by FEMA’s Flood Insurance Rate Maps, County maps (Floodway Maps or Assessor’s Maps), or identified by Public Works to be in a Repetitive Loss Area, will undergo further evaluation by Public Works staff on whether the building me ets FEMA’s definition of substantial improvement/substantial damage (SI/SD). A building that meets FEMA’s SI/SD definition will be required to have the entire building upgraded to meet National Flood Insurance Program (NFIP) standards ( Title 44, Code County of Los Angeles
All-Hazards Mitigation Plan

of Federal Regulations, Section 60.3). Los Angeles County Code Title 26, Section 110.1 requires the County to enforce as a minimum the current Federal Flood Plain Management Regulations defined in Title 44 , Code of Federal Regulations, Section

60.3, for buildings, structures, and grading located in whole or in part in flood hazard areas. (Ord. 2013-0048 § 2, 2013; Ord. 2010-0053 § 2, 2010; Ord. 95-0065 § 3 (part), 1995.)

7.4 Identification and Analysis of Mitigation Strategies Potential mitigation actions were identified for each hazard identified in Section 6 in an effort to ensure as comprehensive a mitigation strategy as possible. Multiple mitigation options were then analyzed against the goals and objectives delineated in this section with a focus on new and existing buildings. A combination of new and ongoing mitigation actions aimed at reducing the effects of the identified hazards were compiled into the list of mitigation actions in the following subsection. This list includes a wide range of potential types of mitigation actions, including:
• Local Plans and Regulations.
• Structure and Infrastructure Projects.
• Natural Systems Protection.
• Education and Awareness Programs.

A notable update to the 2025 AHMP was the integration of human-caused threats and corresponding potential mitigation actions. The AHMP Planning Team also reviewed FEMA’s Mitigation Ideas document to incorporate national best practices in the list of potential mitigation actions.

County of Los Angeles
All-Hazards Mitigation Plan

7.4.1 Mitigation Strategies

01 Title: Support and Expand Countywide Vegetation Management and Fire Prevention Efforts
Source: Los Angeles County Fire Department
Type: Natural Systems Protection
Description: Conduct passive protection measures such as creating defensible space buffers around residential and non-residential structures through the removal of
flammable vegetation, managing and/or reducing
hazardous fuels, creating firebreaks, fire -resistive
landscaping and construction, and clearing dead
vegetation, among others. Engage indigenous
communities to inform vegetation management and fire
prevention practices aligned with Traditional Ecological Knowledge (TEK).

Hazard: Wildfire
Hazard: Severe
Wind/Tornado

02 Title: Enhance Community Engagement in Wildfire Protection and Prevention
Source: Los Angeles County Department of Regional Planning Type: Education and Awareness Programs
Description: Engage residents and businesses in high fire risk communities to educate them on community -focused
mitigation and risk reduction strategies, emergency
preparedness and evacuation readiness, and opportunities to get involved in fire safety -related community initiatives.

Engage indigenous communities to inform protection and
prevention practices aligned with Traditional Ecological Knowledge (TEK).

Hazard: Wildfire
Hazard: Severe
Wind/Tornado

County of Los Angeles
All-Hazards Mitigation Plan

03 Title: Perform Post- Fire Flooding, Debris Flow, and Mud Flow Risk Assessments and Mitigation Activities
Source: Los Angeles County Department of Public Works
Type: Structure and Infrastructure Projects
Description: Following a wildfire, assess burn scar for
significant mud and debris flow risks to produce mud and
debris flow phase maps for first responding agencies to
prepare for potential evacuations. Recommend mitigation strategies to prevent mud and debris flow impacts.

Hazard: Wildfire
Hazard: Flooding

04 Title: Strengthen Operational Continuity Capabilities for Critical Facilities Source: Los Angeles County Department Public Health, among others.

Type: Structure and Infrastructure Projects
Description: Conduct robust continuity planning to ensure the continued performance of essential functions in the event critical facilities are impacted by various hazards.

Build capabilities that support operational continuity such as alternate or uninterrupted power supply, workforce
development and cross -training, emergency
communications, and data backup or failover hardware.

Hazard: Wildfire
Hazard: Extreme Heat
Hazard: Severe
Wind/Tornado
Hazard: Cyber Incidents

County of Los Angeles
All-Hazards Mitigation Plan

05 Title: Incorporate Hazards in Local Planning, Land Use, and Development Codes
Source: Los Angeles County Department of Public Works and Regional Planning Type: Local Planning and Regulations
Description: Develop, maintain, and leverage
opportunities to strengthen relevant ordinances that
govern land use, building codes, and development in
high-risk hazard areas. Incorporate mitigation actions in community planning such as Community Wildfire Plans,
Flood Management Plans, and the County General Plan,
among many others.

Hazard: Wildfire
Hazard: Earthquake
Hazard: Land Movement
Hazard: Severe
Wind/Tornado
Hazard: Flooding

06 Title: Increase Public Awareness of Climate Change Effects on Local Hazards
Source: Los Angeles County Chief Sustainability Office
Type: Education and Awareness Programs
Description: Engage with communities on ways climate
change impacts various natural hazards along with
mitigation actions and available resources for climate
adaptation and resilience. Efforts should focus on how
communities can take action or support existing County
programs including funding available to the public. Public engagement efforts should be accessible, ensure people
with Access and Functional Needs are included in
outreach, and use materials with multiple language
options.

Hazard: Wildfire
Hazard: Extreme Heat
Hazard: Drought
Hazard: Land Movement
Hazard: Severe
Wind/Tornado
Hazard: Flooding

County of Los Angeles
All-Hazards Mitigation Plan

07 Title: Expand Stormwater Management, Drainage, and Outlet Planning Source: Los Angeles County Department of Public Works
Type: Local Planning and Regulations
Description: Continue robust stormwater management
programs. Conduct studies to inform measures to improve outlet and drainage planning and prevent flood damage
to communities in high-risk areas. These efforts should also prevent flood damage to County -maintained road ways,
including evacuation egress and emergency services
ingress, while supporting potential groundwater recharge.

Hazard: Flooding
Hazard: Drought
Hazard: Transportation
Incident

08 Title: Construct and Maintain Localized Flood Control Improvements Source: Los Angeles County Department of Public Works
Type: Structural and Infrastructure Projects
Description: Maintain existing flood control mechanisms
by drainage system maintenance, sediment and debris
clearance, and other actions. Leverage opportunities to construct flood control improvements.

Hazard: Flooding

County of Los Angeles
All-Hazards Mitigation Plan

09 Title: Preserve Floodplains as Public Use Open Spaces Source: Los Angeles County Department of Public Works, among others.

Type: Natural Systems Protections
Description: Preserve and expand public use open spaces that capture stormwater with the aim of reducing localized flooding while also providing green space and
recreational opportunities to communities. Prioritize
floodplains and watersheds in County -owned public use
open spaces near flood risk areas. Use stormwater best
management practices in projects involving open spaces
to support natural water collection and conservation.

Incorporate floodplain preservation into future park
improvements.

Hazard: Flooding

10 Title: Harden Critical Facilities and Infrastructure from Seismic Damage Source: Los Angeles County Department of Public Works
Type: Structure and Infrastructure Projects
Description: Conduct seismic assessments to prioritize
retrofitting and other seismic mitigation actions such as bracing or seismic shutoff valves. Efforts should focus on critical facilities for community lifelines such as hospitals, public safety facilities, utility sites, high -
hazard potential
dams, and transportation assets (i.e., bridges, roadways, airports, and others).

Hazard: Earthquake
Hazard: Land Movement
Hazard: Dam Failure

County of Los Angeles
All-Hazards Mitigation Plan

11 Title: Prevent Impacts to the Transportation System
Source: Los Angeles County Department of Public Works
Type: Structure and Infrastructure Projects
Description: Hazard impacts to the transportation system in Los Angeles County have far -reaching potential for
cascading effects across multiple lifelines. Mitigation activities for multiple hazards should focus on preventing or lessening impacts to transportation. Ac tivities may include stabilization efforts along County -maintained
roads, reinforcing transportation assets, or other seismic mitigation actions.

Hazard: Earthquake
Hazard: Land Movement
Hazard: Transportation
Incident

12 Title: Continue Efforts to Enhance Dam Safety and Reduce Long -Term Vulnerabilities with High Hazard Potential Dams
Source: Los Angeles County Department of Public Works
Type: Structure and Infrastructure Projects
Description: Upgrade infrastructure to ensure the long- term integrity and safe operation of County -owned dam
facilities. Potential actions could include strengthening of dams, sediment management activities, regular
inspections, continuous maintenance, integrating
advanced technologies, and emergency preparedness
efforts.

Hazard: Earthquake
Hazard: Dam Failure

County of Los Angeles
All-Hazards Mitigation Plan

13 Title: Assess Water Resilience in Los Angeles County Source: Los Angeles County Department of Public Works
Type: Local Planning and Regulations
Description: Conduct assessments and studies to monitor the water supply and develop recommendations for other
water systems. Identify potential secondary water sources or other contingency measures for ensuring water system resilience during drought conditions.

Hazard: Drought

14 Title: Expand Drought-Tolerant Landscaping and Design Source: Los Angeles County Chief Sustainability Office and Department of Regional Planning
Type: Natural Systems Protection
Description: Integrate drought mitigation into landscaping and design measures undertaken by the County. Prioritize native and drought -
tolerant plants when selecting
landscaping designs. Use permeable materials for pavers, driveways, walkways, and roadways to reduce r unoff and promote groundwater recharge that incorporate
indigenous- informed practices aligned with Traditional Ecological Knowledge (TEK).

Hazard: Drought

County of Los Angeles
All-Hazards Mitigation Plan

15 Title: Address Urban Heat Islands by Investing in Green Infrastructure and Cooling Strategies
Source: Los Angeles County Chief Sustainability Office, Department of Regional Planning, Department of Economic Opportunity, Department of Public Health, and Department of Public Works, among others.

Type: Local Planning and Regulations
Description: Increase shade cover provided by vegetation such as planting native and drought -tolerant trees along with smaller plants such as shrubs, grasses, and
groundcover. Increase the tree canopy in County parks
and open concrete or asphalt spaces in the public right of way or County-owned parking lots. Conduct assessments
to identify communities considered urban heat islands that are at highest need for an increase in tree canopy or other heat mitigation activities. Advance cooling strategies such as constructing shade structures, installing splash pads, operating cooling centers, modernizing air conditioning systems, and expanding the availability of cool roofing
infrastructure that reflects heat away from buildings.

Ensure mitigation actions address heat impacts faced by people with Access and Functional Needs. Many of these
actions have a secondary benefit mitigating the effects of climate change by promoting carbon sequestration, the
capture and storage of CO2 from the atmosphere.

Additionally, increasing green space and shade cover in urban areas can advance environmental justice.

Hazard: Extreme Heat

County of Los Angeles
All-Hazards Mitigation Plan

16 Title: Increase Coastal Resilience, Prevent Erosion, and Protect Shorelines Source: Los Angeles County Chief Sustainability Office and Department of Beaches and Harbors
Type: Natural Systems Protection
Description: Conduct activities to replace sediment lost due to erosion or coastal storms. Assess the need for other sediment protection measures such as planting certain
types of vegetation. Consider activities that prevent wind from blowing sand off beaches and impa cts from storm
surge in high-risk areas. These actions help protect coastal roadways and other infrastructure along with ensuring
recreation opportunities remain for residents and visitors.

Hazard: Flooding
Hazard: Tsunami

17 Title: Conduct Multi-Discipline Training and Exercise Programs Source: Los Angeles County Sheriff’s Department and Office of Emergency Management
Type: Education and Awareness Programs
Description: Identify opportunities for joint training and exercises for mass violence and cyber incident response across disciplines of law enforcement, fire and emergency medical services, medical examiner, private sector, and others. Each training and exercise shou
ld include mass
violence rescue and evacuation techniques for AFN
populations.

Hazard: Mass Violence
Hazard: Cyber Incidents

County of Los Angeles
All-Hazards Mitigation Plan

18 Title: Strengthen Partnerships and Coordination Among Local Agencies Source: Los Angeles County Sheriff’s Department and Office of Emergency Management
Type: Education and Awareness Programs
Description: Expand collaborative agreements with other agencies to share resources during large -scale
emergencies. Strengthen partnerships with local agencies for resource sharing. Enhance response capabilities
during major incidents.

Hazard: Mass Violence
Hazard: Cyber Incidents

19 Title: Incorporate Mass Violence Prevention and Mitigation Efforts into Special Event Planning
Source: Los Angeles County Sheriff’s Department and Office of Emergency Management
Type: Education and Awareness Programs
Description: Use physical security measures such as
bollards, water -filled barricades, vehicle barriers, and others. Identify mitigation measures for upcoming special events such as the World Cup, Super Bowl, and Olympics.

Conduct special event training on topics such as crowd management, sporting event safety, and stadium
evacuation. Incorporate Family Assistance Center
readiness into special event planning.

Hazard: Mass Violence

County of Los Angeles
All-Hazards Mitigation Plan

20 Title: Extreme Heat Risk Education and Safety Outreach for Residents and Vulnerable Workers
Source: Los Angeles County Chief Sustainability Office, Department of Economic Opportunity, Department of Public Health, and Department of Public Works Type: Education and Awareness Programs
Description: Implement outreach and education to
workers in low -wage and high hazard industries in LA
County that are disproportionately impacted by extreme
heat. Partner with organizations providing services to
people with Access and Functional Needs on heat
response strategies. Expand awareness of cooling centers and other heat respite options for unhoused populations.

Increase workforce development opportunities to expand
the availability of green infrastructure.

Hazard: Extreme Heat

21 Title: Increase Field Response and Coordination Capabilities Source: Los Angeles County Sheriff’s Department and Office of Emergency Management
Type: Education and Awareness Programs
Description: Enhance field coordination capabilities at
large-scale planned events and no- notice incidents such as wildfires, mass violence, and others. Potential actions could include investments in new redundant
communications systems, response vehicles, alert and
warning capabilities, and other field operations
equipment.

Hazard: Wildfire
Hazard: Mass Violence

County of Los Angeles
All-Hazards Mitigation Plan

22 Title: Strengthen Public Health Prevention and Preparedness Measures Source: Los Angeles County Office of Emergency Management, Department of Public Health, Department of Health Services, and Fire Department Type: Education and Awareness Programs
Description: Continue and expand mass vaccination and
immunization efforts. Coordinate healthcare surge
preparedness and response efforts. Conduct disease
surveillance, monitor early warning systems, and
coordinate outbreak response. Educate communities and
businesses about health implications related to wild fire recovery and hazardous materials. Liaise with health
system partners to understand hospital surge capacity
within the County. Maintain and deploy emergency
stockpiles. Incorporate potential climate change-related infectious disease implications into public health
preparedness planning.

Hazard: Public Health
Emergencies

7.5 Status of Previous Mitigation Efforts
Table 7-6 below shows the status of mitigation strategies described in the 2020 AHMP .

Departments have made significant progress on some of these mitigation strategies, partially but not fully completing some of these efforts. As such, each strategy from the 2020 AHMP have been rolled into the mitigation strategies described in this section.

Table 7-6 Status of Mitigation Efforts
2020 AHMP Strategy Status 2025 AHMP Strategy
Red Flag Warning Public
Outreach
Not
Completed/
Ongoing
Enhance Community Engagement
in Wildfire Protection and
Prevention
County of Los Angeles
All-Hazards Mitigation Plan

2020 AHMP Strategy Status 2025 AHMP Strategy
Vegetation Management
Program
Not
Completed/
Ongoing
Support and Expand Countywide
Vegetation Management and Fire
Prevention Efforts
Fireproof Coating of Critical
Facilities
Not
Completed/
Ongoing
Enhance Community Engagement
in Wildfire Protection and
Prevention
Auxiliary Power for Critical
Facilities
Not
Completed/
Ongoing
Strengthen Operational Continuity
Capabilities for Critical Facilities
Earthquake-Resistant Ductile
Iron Pipes Replacement
Not
Completed/
Ongoing
Harden Critical Facilities and
Infrastructure from Seismic
Damage
Watershed Ecosystem
Restoration
Not
Completed/
Ongoing
Preserve Floodplains as Public Use
Open Spaces
Green Streets / Living Streets Not
Completed/
Ongoing
Expand Drought-Tolerant
Landscaping and Design
Coordinated Data Collection
and Database Systems
Not
Completed/
Ongoing
Strengthen Partnerships and
Resource Coordination Among
Local Agencies
Brush Clearance Program Not
Completed/
Ongoing
Support and Expand Countywide
Vegetation Management and Fire
Prevention Efforts
Wildland Urban-Interface
Ordinance
Not
Completed/
Ongoing
Incorporate Hazards in Local
Planning, Land Use, and
Development Codes
Urban Forest Management
Plan
Not
Completed/
Ongoing
Address Urban Heat Islands by
Investing in Green Infrastructure
and Cooling Strategies
County of Los Angeles
All-Hazards Mitigation Plan

2020 AHMP Strategy Status 2025 AHMP Strategy
Community Wildfire Protection
Plans
Not
Completed/
Ongoing
Incorporate Hazards in Local
Planning, Land Use, and
Development Codes
Pre-Disaster Professional
Support
Not
Completed/
Ongoing
Strengthen Operational Continuity
Capabilities for Critical Facilities
Fuel Trailer Project Not
Completed/
Ongoing
Strengthen Operational Continuity
Capabilities for Critical Facilities

7.6 Prioritization and Implementation of Mitigation Actions Potential mitigation actions were prioritized using the FEMA National Risk Index (NRI) score and information from the 2024 Los Angeles Threat and Hazard Identification and Risk Assessment (THIRA), which both address hazards by frequency, severity, and impact. Both the NRI and THIRA follow established processes and use a standardized risk assessment methodology. The NRI incorporat es multiple variables including physical impacts posed by hazards in addition to social vulnerability data that communicates risks specific to a certain community. Table 7-7 provides an overview of the NRI results for Los Angeles County across 18 hazards. Hazards rated as Relatively L o w , N o t A p p l i c a b l e , o r N o R a t i n g w e r e n o t i n c l u d e d i n t h i s A H M P a s t h e y a r e uncommon in frequency in Los Angeles County; all other hazards are c overed in this plan.

Table 7-7 FEMA National Risk Index Hazards
Hazard NRI Score
(out of 100.0)
Score Description Covered in
Plan?
Earthquake 100.0 Very High Yes | Section 6.3
Wildfire 99.9 Very High Yes | Section 6.2
Extreme Heat 98.4 Relatively High Yes | Section 6.4
Tornado 97.6 Relatively High Yes | Section 6.10
County of Los Angeles
All-Hazards Mitigation Plan

Hazard NRI Score
(out of 100.0)
Score Description Covered in
Plan?
Landslide 96.3 Relatively High Yes | Section 6.8
Lightning 95.0 Relatively High Yes | Section 6.2/

6.6 Riverine Flooding 90.8 Relatively Moderate Yes | Section 6.6 Drought 73.8 Relatively Moderate Yes | Section 6.5
Strong Wind 73.5 Relatively Moderate Yes | Section 6.10 Tsunami 63.5 Relatively Moderate Yes | Section 6.10
Winter Weather 48.6 Relatively Low Not Prioritized
Hail 48.1 Relatively Low Not Prioritized
Coastal Flooding 43.3 Very Low Not Prioritized
Avalanche 33.7 Very Low Not Prioritized
Cold Wave 0.0 No Rating Not Prioritized
Hurricane N/A Not Applicable Not Prioritized
Ice Storm N/A Not Applicable Not Prioritized
Volcanic Activity N/A Not Applicable Not Prioritized
The THIRA is a process that communities undertake to assess risk and set capability targets to focus their preparedness efforts and strengthen response and recovery capabilities. There are three primary focuses of the THIRA: threat and hazard identification, impacts analyses that include the specific demographics of the community, and a description of existing response and recovery capabilities. The 2024 Los Angeles/Long Beach THIRA was reviewed as part of this hazard mitigation planning effort and all threats and hazards identified were included as part of this AHMP .

Additionally, the THIRA’s identification of several human-caused threats with potential to impact Los Angeles County influenced the decision to include such threats in this AHMP . Table 7-8 shows a crosswalk of the hazards and threats identified in the THIRA and their corresponding sections in this AHMP .

County of Los Angeles
All-Hazards Mitigation Plan

Table 7-8 2024 THIRA and 2025 AHMP Crosswalk
2024 THIRA
Hazard/Threat Name
2025 AHMP Hazard/Threat
Name
Covered in Plan?
Biological Attack Public Health Emergencies Yes | Section 6.14 Complex Coordinated
Terrorist Attack
Mass Violence Yes | Section 6.11
Cyber Attack Cyber Incident Yes | Section 6.12
Earthquake Earthquake Yes | Section 6.3
Flood Flooding Yes | Section 6.6
Pandemic – Human Public Health Emergencies Yes | Section 6.14 Radiological Attack Public Health Emergencies Yes | Section 6.14 Transportation Accident Transportation Incident Yes | Section 6.13 Wildfire Wildfire Yes | Section 6.2
Additional criteria used to prioritize potential mitigation actions also included the following components:
• Actions that prioritize equity and integrate vulnerable populations, including people with AFN.
• Potential benefits of the action to prevent a major hazard. • Actions that have social support to build a culture and practice of resilience. • Cost of the action versus the potential benefit to prevent a major hazard. • Availability of funding and actions that support grant requirements. • Political support to remedy or prevent a major health or safety hazard. • Actions that are technically, legally, environmentally, and economically feasible. • Actions that the County has the administrative capabilities to implement. • Actions that are related to mitigating long-term vulnerabilities to County- owned High Hazard Potential Dams will automatically be given a HIGH priority.

7.6.1 Priority Levels
• High-Priority Mitigation Actions: are essential and require immediate attention to address critical risks and safeguard life, property, or essential systems.

County of Los Angeles
All-Hazards Mitigation Plan

• Medium-Priority Mitigation Actions: are important but less urgent, supporting overall risk reduction and resilience goals while allowing for planned implementation.
• Low-Priority Mitigation Actions: address lower -risk concerns or long -term objectives and can be deferred without immediate impact to safety or core functions.

7.6.2 Changes in Criteria
The 2014 Los Angeles County AHMP’s Mitigation Action Matrix was prioritized using the Social, Technical, Administrative, Political, Legal, Environmental, and Economic (STAPLEE) method, which FEMA had recommended as a prioritization procedure in the early t o mid -2000s. The 2020 AHMP replaced the use of STAPLEE with a more streamlined prioritization process that included the following:
• T o r e m e dy o r p r e ve n t a m a j o r h e a l th / s af e ty h a z a r d, a m i ti g a ti o n p r o j e c t m u s t have political support.
• To build a culture and practice of disaster resilience, a mitigation project must have social support.
• To meet FEMA HMA grant criteria, a mitigation project must be technically, legally, environmentally, and economically feasible and the jurisdiction must have the administrative capabilities to implement it.

This prioritization method used in the 2020 AHMP has been adapted and incorporated into the prioritization criteria described previously in Section 7.6.

7.7 Integration with Other Plans
The County of Los Angeles ensures that mitigation is a countywide effort with multiple departments contributing to critical activities that reduce hazard risks. These actions are captured in other discipline-specific plans in addition to the AHMP , including those listed in Table 7-9.

County of Los Angeles
All-Hazards Mitigation Plan

Table 7-9 AHMP Integration with Other Plans
Plan Authored By Hazard(s) Covered
in Plan?
Comprehensive
Floodplain
Management Plan
Los Angeles County
Department of Public
Works
Flood Yes
Repetitive Loss Area
Analysis Report
Los Angeles County
Department of Public
Works
Flood
Yes
Climate Action Plan Los Angeles County
Department of Regional
Planning
Wildfire
Extreme Heat
Flooding
Drought
Yes
Sustainability Plan Los Angeles County Chief
Sustainability Office
Wildfire
Extreme Heat
Flooding
Drought
Yes
County Fire Plan Los Angeles County Fire
Department
Wildfire Yes
County of Los Angeles
All-Hazards Mitigation Plan

7.8 Mitigation Action Plan
Table 7-10 represents a Mitigation Action Plan to reduce risks of the hazards identified in this AHMP . Notably, many County departments include discipline -specific mitigation actions within other related plans mentioned in the above section. Some actions that mitigate risk of natural hazards that are covered elsewhere may not be explicitly listed or may be referred to in general terms while specific details are available in other related plans.

Table 7-10 Mitigation Action Plan
Action
No.

Priority Hazard
Action Name
Potential
Funding
Source
Expected
Time
Frame
Lead
Agencies
01 HIGH
Wildfire Support and Expand Countywide
Vegetation Management and Fire
Prevention Efforts
HMGP Annual LACoFD, PW
Severe
Wind/Tornado
02 HIGH
Wildfire Enhance Community
Engagement in Wildfire
Protection and Prevention
HMGP Quarterly LACoFD, DRP ,
OEM, LASD Severe
Wind/Tornado
03 HIGH
Wildfire Perform Post-Fire Flooding,
Debris Flow, and Mud Flow Risk
Assessments and Mitigation
Activities
HMGP , FMA Annual PW, LACoFD,
OEM
Flooding
04 HIGH
Wildfire UASI, SHSP Annual OEM, PW,
DPH, Extreme Heat
County of Los Angeles
All-Hazards Mitigation Plan

Action
No.

Priority Hazard
Action Name
Potential
Funding
Source
Expected
Time
Frame
Lead
Agencies
Severe
Wind/Tornado
Strengthen Operational
Continuity Capabilities for Critical
Facilities
LACoFD,

LASD, ISD
Cyber Incidents
05 HIGH
Wildfire
Incorporate Hazards in Local
Planning, Land Use, and
Development Codes
HMGP , FMA 1-3 Years D R P, PW
Earthquake
Land Movement
Severe
Wind/Tornado
Flooding
06 MEDIUM
Wildfire
Increase Public Awareness of
Climate Change Effects on Local
Hazards
FMA, Prop 4 Annual DRP, CSO,
CEO
Extreme Heat
Drought
Land Movement
Severe
Wind/Tornado
Flooding
County of Los Angeles
All-Hazards Mitigation Plan

Action
No.

Priority Hazard
Action Name
Potential
Funding
Source
Expected
Time
Frame
Lead
Agencies

07 HIGH

Flooding Expand Stormwater
Management, Drainage, and
Outlet Planning
FMA 1-5 Years PW
Drought
Transportation
Incident
08 HIGH Flooding Construct and Maintain Localized
Flood Control Improvements
FMA 1-5 Years PW
09 MEDIUM Flooding Preserve Floodplains as Public
Use Open Spaces
FMA, Prop 4 1-5 Years PW, DRP, DPR
10 HIGH
Earthquake Harden Critical Facilities and
Infrastructure from Seismic
Damage
HMGP 1-5 Years PW, ISD
Land Movement
Dam Failure
11 MEDIUM
Earthquake Prevent Impacts to the
Transportation System
HMGP 1-5 Years PW, LASD
Land Movement
Transportation
Incident
County of Los Angeles
All-Hazards Mitigation Plan

Action
No.

Priority Hazard
Action Name
Potential
Funding
Source
Expected
Time
Frame
Lead
Agencies
12 HIGH
Earthquake Conduct Seismic Strengthening
at County-Owned Dams
FMA, HHPD 1-5 Years PW
Dam Failure
13 MEDIUM Drought Assess Water Resilience in Los
Angeles County
Prop 4 1-5 Years PW, DRP
14 MEDIUM Drought Expand Drought-Tolerant
Landscaping and Design
Prop 4 1-5 Years DPR, DRP ,

PW, CSO
15 HIGH Extreme Heat
Address Urban Heat Islands by
Investing in Green Infrastructure
and Cooling Strategies
Prop 4 1-5 Years CSO, DRP,

DEO, DPH,

PW, DPR
16 HIGH
Flooding Increase Coastal Resilience,
Prevent Erosion, and Protect
Shorelines
FMA, Prop 4 1-5 Years CSO, DBH,
PW
Tsunami
17 HIGH
Mass Violence Conduct Multi-Discipline Training
and Exercise Programs
UASI, SHSP 1-5 Years LASD, OEM,
LACoFD
Cyber Incidents
18 MEDIUM
Mass Violence Strengthen Partnerships and
Resource Coordination Among
Local Agencies
UASI, SHSP 1-5 Years LASD, OEM,
LACoFD
Cyber Incidents
County of Los Angeles
All-Hazards Mitigation Plan

Action
No.

Priority Hazard
Action Name
Potential
Funding
Source
Expected
Time
Frame
Lead
Agencies
19 MEDIUM Mass Violence
Incorporate Mass Violence
Prevention and Mitigation Efforts
into Special Event Planning
UASI, SHSP 1-5 Years LASD, OEM,
LACoFD
20 HIGH Extreme Heat
Extreme Heat Risk Education and
Safety Outreach for Residents
and Vulnerable Workers
Prop 4 1-5 Years CSO, DEO,

DPH, PW,
DAD
21 HIGH
Public Health
Emergencies
Strengthen Robust Public Health
Prevention and Preparedness
Measures

UASI, SHSP ,

PHEP , HPP
1-5 Years DPH, OEM,
DHS,
LACoFD
22 MEDIUM
Wildfire Increase Field Response and
Coordination Capabilities
UASI, SHSP 1-5 Years LASD, OEM,
LACoFD
Mass Violence
Agency Key:

CEO = Los Angeles County Chief Executive Office
CSO = Los Angeles County Chief Sustainability Office
DAD=Los Angeles Department of Aging and Disabilities
DBH = Los Angeles County Department of Beaches and Harbors DEO = Los Angeles County Department of Economic Opportunity DHS = Los Angeles County Department of Health Services
DPH = Los Angeles County Department of Public Health
DPR = Los Angeles County Department of Parks and Recreation PW = Los Angeles County Public Works
DRP = Los Angeles County Department of Regional Planning ISD = Los Angeles County Internal Services Department

LACoFD = Los Angeles County Fire Department.

LASD = Los Angeles County Sheriff’s Department
OEM = Los Angeles County Chief Executive Office - Office of Emergency Management
Grant Program Key:

FMA = Flood Mitigation Assistance
HMGP = Hazard Mitigation Grant Program
HPP = Hospital Preparedness Program
PHEP = Public Health Emergency Preparedness
SHSP = State Homeland Security Program
UASI = Urban Area Security Initiative
County of Los Angeles
All-Hazards Mitigation Plan

8 Plan Maintenance
County of Los Angeles
All-Hazards Mitigation Plan

8.1 Community Participation in Plan Maintenance
The Hazard Mitigation Plan will be reviewed regularly, acknowledging the dynamic nature of hazard landscapes and the evolving understanding of risks. Stakeholders’ engagement will be prioritized throughout the development and monitoring process, fostering transparency and accountability.

To maintain transparency and community involvement, the County has outlined several measures for continued public participation:
• Public Access to Hazard Mitigation Documents: A copy of the 2025 AHMP will be maintained on the Los Angeles County Hazard Mitigation Program website along with contact information. Los Angeles County OEM will notify the public of any changes or updates, including mitigation projects identified in the plan as they are implemented, via social media, and traditional local media channels. • Annual Public Engagement Opportunities: Los Angeles County OEM will endeavor to hold multiple in -person public engagement opportunities for hazard mitigation to keep the public informed of progress on hazard mitigation projects, obtain ongoing public feedback, and educate the public about the County’s hazard mitigation efforts.
• Online Portal: A Los Angeles County Hazard Mitigation Program website will be established to provide the public with more information on hazard mitigation and project updates. This portal will serve as a mechanism to obtain continuous public feedback as projects are imp lemented and offers access to mitigation resources.
• Standing Advisory Committee: The Hazard Mitigation Advisory Committee will be expanded to a standing status and will meet at least once per year or more often as determined necessary to support hazard mitigation projects. The standing Hazard Mitigation Advisory Committee will be comp rised of representatives from diverse community groups to provide ongoing input and oversight of hazard mitigation efforts. The standing Hazard Mitigation Advisory Committee will also serve as an important forum for future update s o f t h e A H M P.

These activities ensure that the community remains informed and actively engaged in the plan’s implementation and maintenance.

County of Los Angeles
All-Hazards Mitigation Plan

8.2 Monitoring, Evaluation, and Maintenance
To ensure the continued effectiveness of this All-Hazard Mitigation Plan (AHMP), effective monitoring and evaluation will be conducted throughout the plan implementation period. Regular assessments will monitor progress and evaluate the achievements of the intended outcomes. Performance metrics will be developed to quantify the impact of each mitigation action, allowing for data driven adjustments and refinements.

The plan will be reviewed annually to assess progress on mitigation actions. Annual review will include the following elements:
• Annual Review Worksheets: Every year, LA County OEM will email each member of the Hazard Mitigation Advisory Committee an Annual Review Worksheet to complete. As shown in Appendix E, the Annual Review Worksheet reflects the FEMA Local Hazard Mitigation Plan Review Tool and includes the following sections: planning process, hazard profile, risk assessment, and mitigation strategy. Each member of the Hazard Mitigation Advisory Committee will email completed worksheets back to LA County OEM to review. LA Count y OEM will summarize these findings and email them out to the committee.

Additionally, the findings from the review worksheets will be presented to the full Hazard Mitigation Advisory Committee at its next regular meeting. • Mitigation Progress Project Reports: Mitigation actions will be monitored and updated using the Mitigation Project Progress Report. During each annual review, each department or agency currently administering a mitigation project will submit a progress report to LA County OEM. For projects t hat are being funded by a FEMA mitigation grant, FEMA quarterly reports may be used as the preferred reporting tool. As shown in Appendix E, the progress report will discuss the current status of the mitigation project, including any changes made to the project, identify implementation problems, and describe appropriate strategies to overcome them.
• Post-Incident Mitigation Review: Following a major disaster event impacting Los Angeles County, a post-disaster review will be initiated by LA County OEM to evaluate the need to update the AHMP based on the circumstances of the disaster and incorporate any specific mitigation actions requ ired due to the County of Los Angeles
All-Hazards Mitigation Plan

incident. If LA County OEM finds that an update to the AHMP is needed, the Hazard Mitigation Advisory Committee will be convened to begin drafting the update.

8.3 Criteria for Updating the Hazard Mitigation Plan
The All-Hazards Mitigation Plan (AHMP) is required to be updated every five years in compliance with the Disaster Mitigation Act of 2000 (DMA 2000) and FEMA guidance (44 CFR § 201.6). The update process is not merely an administrative requirement but a critical mechanism to evaluate the plan’s effectiveness in reducing risk and guiding mitigation strategies.

1. Review of Past Actions and Effectiveness
The update process begins with a thorough review of the mitigation actions outlined in the previous plan. This includes:
• Evaluating the implementation status of each action (completed, in progress, not started).
• Assessing the impact and effectiveness of completed actions in reducing hazard risk.
• Determining if the objectives are still relevant or require modification based on new data or circumstances.

2. Integration of New Data and Changing Conditions
• Hazard profiles and risk assessments are updated with new hazard event data, climate science, and changes in development or land use. • Demographic shifts and infrastructure changes are reviewed to reassess vulnerability.
• Technological advancements or improved modeling tools (e.g., Hazus, National Risk Index) are incorporated to refine risk analysis.

3. Community and Stakeholder Input
The update process must actively include community participation to maintain transparency and ensure the plan reflects local priorities. This includes:

County of Los Angeles
All-Hazards Mitigation Plan

• Public workshops and surveys.
• Targeted outreach to vulnerable populations including those with Access and Functional Needs (AFN).
• Feedback from County departments, cities, NGOs, and regional partners.

4. Performance Evaluation and Metrics
To ensure effectiveness, the plan maintenance strategy includes:
• Annual progress reports that monitor implementation progress and identify barriers.
• Metrics to evaluate the reduction of risk or exposure over time. • Documentation of lessons learned from real events and exercises to inform changes.

5. Revision of Goals, Objectives, and Actions
Based on the evaluation findings, the plan’s goals and mitigation actions are revised to improve alignment with current capabilities, risk levels, and funding opportunities.

Each updated action includes:
• Clear responsibilities.
• Realistic timelines.
• Evaluation metrics to measure future success.

8.4 Plan Update
The 2025 LHMP includes an updated methodology for future revisions, ensuring compliance with federal and state guidelines. A full plan update will occur every five years.
• 2030 AHMP Update Kickoff: LA County OEM will convene the Hazard Mitigation Advisory Committee for a meeting to review the worksheet findings and endeavor to begin the process of updating the AHMP in approximately November 2028. The planning process should begin a minimum of 18 months prior to the plan’s expiration. LA County OEM, in consultation with the Hazard Mitigation Advisory Committee, will develop a work plan for the update, conduct County of Los Angeles
All-Hazards Mitigation Plan

research and review relevant documentation, determine hazards to be included in the 2030 AHMP , and begin the process to draft an updated AHMP . • Plan Submission and Adoption: Once updated, the plan is submitted to Cal OES and FEMA for review . Upon conditional approval, it must be adopted by the Los Angeles County Board of Supervisors and participating jurisdictions to maintain eligibility for FEMA Hazard Mitigation Assistance (HMA) grants.

8.5 Integration with Other Plans
Los Angeles County is committed to ensuring that hazard mitigation planning is not a standalone effort, but a fully integrated component of broader County planning initiatives. By strategically weaving the goals, objectives, and actions of the All-Hazards Mitigation Plan (AHMP) into a variety of local and regional plans such as the General Plan, Capital Improvement Plans, Climate Action and Adaptation Plans, and departmental strategic plans ; the County promotes a more cohesive and effective approach to buil ding long-term resilience. This integration is achieved through ongoing collaboration with County departments, cities, and regional agencies to align land use, infrastructure development, and emergency preparedness efforts with identified hazard risks. Emb edding hazard mitigation principles into existing policies and planning mechanisms ensures that they become an inherent part of decision- making processes, project funding prioritization, and long -term investment strategies ultimately reducing vulnerabilities and enhancing the resilience of communities across Los Angeles County.

The Los Angeles County AHMP will be shared across all jurisdictions within the operational area. Those jurisdictions will have the opportunity to incorporate the 2025 AHMP into their established planning process. The Hazard Mitigation Advisory Committee will assess the plan at a yearly basis, acknowledging the dynamic nature of hazard landscapes and the evolving understanding of risks. The OEM Hazard Mitigation Program will make the AHMP available for all county departments to incorporate into departmental planning efforts, and other relevant documents produced by Los Angeles County departments.

County of Los Angeles
All-Hazards Mitigation Plan

9 Plan Adoption

County of Los Angeles
All-Hazards Mitigation Plan

9.1 Plan Adoption Overview
Plan Adoption addressed Element F of the Local Mitigation Plan Regulation Checklist under single jurisdiction plan requirement.

The Los Angeles County Board of Supervisors officially adopted the 2025 All Hazard Mitigation Plan (AHMP) through a formal resolution on September 9, 2025. A scanned copy of the resolution is included in Appendix F. The Los Angeles County Office of Emergency Management (OEM) will retain the resolution for its records, while copies will be submitted to both Cal OES and FEMA.

This Plan adoption completes the mitigation planning process and department agencies, stakeholders, and community’s commitment to the goals and actions. It also recognizes the current planning process and acknowledges changes from the past five years and validates the priorities for hazard mitigation actions. It makes the community eligible for certain FEMA assistance that can fund some mitigation actions.

After being adopted by the Los Angeles County Board of Supervisors, the 2025 AHMP transitions into the implementation phase. The success of the plan hinges on the integrating its mitigation strategies and actions into the local plans and policies. The mitigation action items collectively establish a robust framework to guide the County’s hazard mitigation strategies over the next five years. To ensure these strategies are effective, actionable and well aligned with the county’s long term resilience goals, the Planning Advisory Committee has set clear objectives. Their prioritized approach focuses on seamlessly blending mitigation actions with current policies, plans, and emphasizing collaboration and coherence throughout.

County of Los Angeles
All-Hazards Mitigation Plan

Appendices

APPENDIX D

CITY OF POMONA WATER RATE STRUCTURE

RESOLUTION NO. 2019- 127

ARESOLUTION OF THE CITY COUNCIL OF THE CITY OF POMONA

APPROVING NEW RATE STRUCTURES FOR WATER AND

RECYCLED WATER FEES AND SERVICE CHARGES AND

INCRE ASING SEWER SERVICE FEES
WHEREAS, Chapter62 of the PomonaCity Code, Article IV, Municipal Water Utility, Section62-195and62-291, establishesthe City's ability to chargebimonthlyfeesfor the supply of water and recycled water to customers within and outside the City of Pomona, and established the City Council' s authority to set water and recycled water rates by resolution; WHEREAS, Chapter 62 of the Pomona City Code, Article V, Sewer Disposal, Section 62-400, establishesthe City' s ability to charge bimonthly fees for sewer services to customers, and establishesthe City Council' s authority to set sewerservice ratesby resolution; WHEREAS, this resolution adjusting water, recycled water, and sewer service rates shall apply only to Chapter 62 of the Pomona City Code, Article IV and V, Municipal Water Utility and Sewer Disposal, respectively;
WHEREAS, the City previously retained Raftelis Financial Consultants, an independent financial consultant to review the City' s water, recycled water, and sewer utilities to determine whether rates for service charges are sufficient to meet increased costs of service, and to prepare a cost of service analysis, and rate study (the "Study"); WHEREAS, based on the results of the Study ( a copy of which is available for inspection at the office of the City Clerk, and was also posted on the City' s website), increases to the rates for water, recycled water, and sewer service fees and chargesare necessary; WHEREAS, the proposed potable water rate structure includes a fixed service charge imposed on a bimonthly basis, and a commodity charge. The fixed service charge includes a meter service charge, determined based on the size of the meter serving the property (measured in inches), and recovers the cost to maintain and replace meters as well as a portion of extra- capacity related costs, and a customer service component, which is the same for all meters regardless of size. The proposedcommodity chargeis basedon the amount of water consumed, measured in dollars per hundred cubic feet (" CCF") delivered to the property, and is divided into domestic and irrigation customer classes based on shared patterns of usage; WHEREAS, the proposed potable water rate structure also includes fire service charges for certain properties in the City that have private fire service meters installed, and which is charged based on the size of the fire meter serving the property; WHEREAS, the proposed recycled water rate structure includes a commodity charge, which is determinedbasedon the numberof acrefeet of recycledwaterdeliveredto a property, and a bimonthly recycled water service charge, based on the size of the recycled water meter serving the property;
WHEREAS, the proposed sewer service charges include a bimonthly service charge, which is uniform for all customers, and a consumption charge, which is applied per unit of water consumption defined, as the average of two complete months data within the period of December of the previous year through the following March,
WHEREAS, the proposed rate structures are for a period of five years, and are proposed to take effect October 1, 201.9, and to increaseeachJanuary I thereafter commencing January 1, 2020, through and including January 1, 2023;
WHEREAS, the proposed potable water, recycled water, and sewer service fees collectively, the " Fees") are property- relate fees within the meaning of article X111D of the California Constitution;
WHEREAS, the revenues derived from the Fees will not exceed the funds required to provide the services for which the Fees are imposed, and will be used exclusively for the operationandmaintenanceof the City' s potablewater, recycled water, and sewersystems; WHEREAS, the Fees are equitable to all customer classes; WHEREAS, the amount of the Fees will not exceed the proportional cost of the service attributable to eachparcel upon which they areproposed for imposition; WHEREAS, the Fees will not be imposed on a parcel unless the service for which such Feesareimposed, is actually usedby, or immediately available to, the owner of the parcel; WHEREAS, article X111. D, section 6 of the California Constitution (" Article XIII D") requires that prior to imposing any increaseto, the Fees, the City shall provide written notice (the Notice") by mail of the new or increased Fees to the record owner of each parcel upon which the Fees are proposed for imposition and any tenant directly liable for payment of the Fees, the amount of the Fees proposed to be imposed on each parcel, the basis upon which the Fees were calculated, the reason for the Fees, and the date time and location of a, public hearing (the Hearing") on the proposed Fees;
WHEREAS, on July 19, 2019, the City distributed notices as required by Article XIII D regarding the City Council' s considerationof the proposedrate adjustmentsto the Feesat the September 1.6, 2019, public bearing to all property owners of record and utility customers in accordance with Article XIII D, Section 6(a)( 1) of the California Constitution, and Government Code Section 53755;
WHEREAS, on September16, 2019, the City Council held a duty noticed public hearing on the proposed Fees contained in this Resolution, and at that time invited oral and written comments from the public;
WHEREAS, upon close of said public bearing, the City did receive written protests to the proposed Fees; and
WHUEAS, the City Council now desires to establish rates for the Fees, effective October 1, 2019, at the rates and subject to increases on the dates set forth in the schedules included as Exhibit A hereto.

NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Pomona as follows:

SECTION L That the adoption of this Resolution falls within a statutory exemption from environmental review pursuant to sections 15273, 15060(c)(2) of the State Guidelines for Implementation of the California Environmental Quality Act ( CEQA),, which pertain to the establishment, modification, structuring, restructuring, or approvalof ratesandchargesby public agencieswhich the public agencyfinds arefor the purposeof meetingoperating expenses, and pertain to activities that will not result in a direct or reasonablyforeseeableindirect changeto the environment and that are not defined as a project under CEQA Regulations.

SECTION 2. That after consideringthe materialpresentedin the Study, the City Council herebyfinds as, follows:
a) Revenuesderived from the Feesdo not exceed the funds required to provide the property related service;
b) Revenuesderived from the Feesare not used for any purpose other than for which the Fees or charges is imposed;
c) The amount of the Fees imposed upon any parcel or person does not exceed the proportional cost of service attributable to the parcel; d) The Fees are imposed for services that are actually used by, or immediately available to, the owner of the property upon which the Feesareimposed.

SECTION 3. That after receivingpublic commentand testimonyon the new fee structure for water, sewer and recycled water services provided, and absent a majority protest to the proposed fee increases, the new fee schedulefor water, sewer and recycled water fees and chargesareherebyapprovedassetforthin Exhibit "A" attachedheretoandincorporatedherein by this reference.

SECTION 4. That the new fee schedule for water, sewer and recycled water services shallbeimplementedbeginningOctober1, 2019, andshallbeincreasedannuallyonthedatesset forth in Exhibit " A" hereto, up to the maximum rates set forthorth in Exhibit " A" hereto. To the extentanyotherresolutionof the City conflicts, with theprovisionssetforth herein, it is the explicit intentof theCity Councilthattheprovisionsof this Resolutionshallsupersede.

SECTION 5. That all water charges subject to the adjusted fee schedule may resume annualCPl adjustment, asoutlined in City CodeSection62-271, startingonJanuary1, 2024.

SECTION 6. The City Clerk shall attestand certify to the passageand adoption of this Resolution.

PASSED, APPROVED AND ADOPTED this 16"' day of September, 2019.

CITY OF P A:

Ti
an 0
Mayor
APPROVED ASTO FORM: ATTEST:

Sonia Carvalho
m
Rosalia A. Butt r, JMCCity Attorney City Cleric
I, HEI-EBY CERTIFY thattheforegoingresolutionwasduly adoptedby the City Councilof the Cityof Pomonaata regularmeetingthereofheldonSeptember16, 2019bythefallowingvote of the Council:.

AYES: Garcia, Gonzalez, Lustro, Ontiveros- Cole, Preciado, Torres, Sandoval NOES: None
ABSTAIN: None
ABSENT None
LosaliaA. .Bu ler, MMC
City Clerk
Resolution No. 2019- 127, Exhibit " A"
Rate Schedule
Bimonthly Potable,Water ServiceCharge
Meter October 1, 2019 January 1, 2020 January 1, 2021 January 1, 2022 January 1, 2023 5/ 8111 $

41. 29 $ 45. 52 50- 19 $ 55. 33 $- 59. 21 3/ 4" $ 60. 92 $ 67. 17 74. 05 $ 81. 64 $ 8735 r 100. 18 110. 45 $ 121. 77 134. 25 $ 143, 65
1- 1/ 2" $ 198. 33 218. 65 $ 241. 07 $ 26537 $ 284. 38 2m'
316. 10 $ 348. 50 $ 384. 22 $ 423. 60 $ 453. 26 2"
3"' 590. 91 $ 65'1. 48 $ 718. 25 791. 87 $ 847. 31 411 $
98149
1 1, 084. 30 $ 1, 195. 44 1, 317. 97 1,41M123
6"' $ 1, 964. 95L2, 16636 $ 2, 388. 41 $, 2, 633. 22 $ 2,817. 55 81" $
3, 142. 70 3, 464. 83 3, 819. 97 $ 4, 211. 52 $ 4, 506. 33 1w $ 4, 51635 $ 4, 979, 71 $ 5, 490. 13 6, 05187 $ 6, 476. 57 Potable Water Commodity Rate Structure
Water Use October 1, 2019 January 1, 2020 January1, 2021 January 1, 2022 January 1, 2023 Domestic Cost per CCF Cost per CCF Cost per CCF Cost per CCF Cost per CCF 1- 13 unfits 1. 77 1. 95 2. 15 2. 37 2. 54
14- 35 Units 1 2. 24 2. 47 1 2. 72 3. 00 3. 21
36 Units and Over 2. 36 2. 60 2. 871 3. 16 3. 38
Irrigation
1- 13 Units 1, 881 2. 07 2. 281 2. 51 2. 69
13- 35 Units 2, 601 2. 87 3. 161 3. 48 372
2,6513 Over 29211 L. 22 3. 55
Bimonthly Recycled Water Service Charge
Meter October 1, 2019 January1, 2020 _January1, 2021January1, 2022lanua!y 1, 2023211 163. 22 $ 69. 70 $ 76. 84 $ 84, 72 $ 90. 65 311
118. 18 $ 130. 30 $ 143. 65 $ 158. 37 $ 169., 46 4" 196. 70 $ 216. 86 $ 239. 09 $ 263- 59 $ 282. 05 601
392. 99 $ 433. 27 $ 477, 68 $ 526. 64 $ 563. 51 811
628. 54 $ 692. 97 $ 763, 99 $ 842. 30 $ 901. 27 1011 $
903. 35 $ 995. 94 $ 1, 098. 03 $ 1, 210. 57 $ 1, 295. 31 1211 $
1, 963. 33 $ 2, 164. 57 1 2, 386- 43 $ 2, 631. 04 $ 2, 81512 1401 $
2, 944. 78 $ 3, 246. 62 $ 3, 579. 40 $ 3, 946. 29 $ 4, 222, 53 16" $ 3, 926. 24 $ 4, 328. 68 $ 4, 772. 37 $ 5, 261. 54 $ 5, 629. 85 L. 1 $ 5, 410. 74 $ 5, 965. 34 $ 6, 576, 79 $ 77037. 17 Recycled Mater Commod ty RateStructure( CostPer Acre Foot) f-October l, 201911 January i, 2020 January 1, 2021 January 1, 2022 January 1, 2023' 1_$ 566. 47'. L$_ 589. 42 $ 546. 92 1 $ 566. 55 1 $ 587. 741 Resolution No, 2019- 127, Exhibit" ,"
Sewer Rates
October 1, 2019 January 1, 2020 January J'., 2021 Jar7ua 1, Zg22 January , X023 Bimonthly Service Charge $ 9. 39 1 $ 9. 96 1 $ 1 . 56 $ 11. 19 $ 11. 75 Pate Per Unit of Consumption $ 0130 1 $ 0, 74 $ 0. 78 0. 83 $ 9. 87 Faire Service Rates
Size October 1, 2019 January 1, 2020 January 1, 2021 January 1, 2022 January 1, 2023 2:" or less $ 8. 64 53 10. 50 $ 11, 5$ ' $ 1.2. 39 311 $

25. 102. 7. 67 $ 30. 51. $ 33..63 $ 35.99
41° $

53. 48 $.... 58. 96 $ _ 65. 01 71.. 67 $ 76. 69 61'
155. 36 $ 171. 28 $ 188. 84 $ 2..08. 19 $ 222. 76 81'" $
331. 07 $ 365. 00 402. 41 $ 443. 66 474. 72
10"' $ 595. 37 $ 656. 40 723. 68 $ 797. 86 $ 853. 71 121"
961. 69 $ 1, 060. 27 $ 1, 168. 95 1, 288. 76 $ 1, 378. 97 RESOLUTION NO. 2019- 128

A RESOLUTION OF TIRE CITY COUNCIL OF THE CITY OF' POM,ONA

CHANGING WATER RATES FOR TEMPORARY CONTRACTOR

METER WATER USAGE AND SETTING AVAILABILITY PRICING

FOR WHOLESALE RECYCLED ' AT ER CUSTOMERS SELLING

WATER OUT SIDETME AREA SERVED BY THE CITY
WHEREAS, Chapter62of thePomonaCityCode, ArticleIV, MunicipalWaterUtility, Section62-297establishestheCity's abilityto chargefeesfor thetemporarysupplyof water throughconstructionwatermetersandthe City Council's authorityto setwaterservicesbyresolution; WHEREAS, this resolution adjusting rates for water for temporary service for contractors shall apply only to Chapter 62 of the Pomona City Code, Article IV, Municipal Water Utility;
WHEREAS, a noticeof theSeptember16, 2019, publichearingon theproposedrate adjustmentswas published in, the Inland Valley Daily Bulletin on September6and September 13, 2019;
WHEREAS, for eachfee, theCity completedacostof servicestudyandhasdeterminedthe rates are appropriate; WHEREAS, the supplyof waterfor temporaryservicefor contractorsshallbesubjectto a surcharge, and added to the amount of water used in each tier, equal to that levied upon the City by the Metropolitan Water District and/or other suppliersof imported water asa part of their water conservation plan as constituted or as modified;
WHEREAS, the City is the purveyor of potable, nonpotableand recycledwater within its serviceareaandhasa contractwiththeSanitationDistrictof LosAngelesCountytoreceive 2/3 of the recycled water produced at the District' s Pomona WastewaterTreatment Plant; WHEREAS, theCity canactasa wholesalerandsupplyrecycledwaterto customers wholatersupplysaidwaterto usersoutsideof theareaservedbytheCity; WHEREAS, the City can supply water to customerswho utilize recycledwater in areas not servicedby the City and servedby anotherwater provider; WHEREAS, the City' s primary objectiveis to supply recycledwater to recycledwater customers within the area servedby the City;
WHEREAS, in the surnmertheremay be times whenrecycledwateravailableto the City is insufficientto meetdemands, in suchinstancesthe City mustmix potablewaterinto the recycled water system, which substantially increases the cost for providing recycled water; WHEREAS, when the demand for recycled water reaches the threshold that, requires potable water be used to increase available recycled water, threshold rates will apply to any customer who usesrecycled water to, sell for useoutside of the areaservedby the City, All users in the areaservedby City will continue to be chargedthe applicable rate, dependingon usage; WHEREAS, this resolution delineates how recycled water will be allocated to City customers and what rate each customer will be billed for the water they receive; WHEREAS, the rates established pursuant to this resolution are imposed for a specific government service or product provided directly to the payor that is not provided to those not charged, and which does not exceed the reasonablecoststo the local government of providing the serviceor product, andthe costof serviceanalysissupportingthe ratesis on the with the City Clerk and available for inspection.

NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Pomona as follows:

SECTION 1. The adoption of this Resolution falls within a statutory exemption from environmental review pursuant to sections 15273, 15060( c)( 2) of the State Guidelines for Implementation of the California Environmental Quality Act ( CEQA), which pertain to the establishment, modification, structuring, restructuring, or approval of rates and charges by public agencieswhich the public agency finds are for the purpose of meeting operating expenses, and pertain to activities that will not result in direct or reasonably foreseeableindirect changeto the environment and that are not defined as, a project under CEQA Regulations; SECTION 2. That after review of cost of service analysis for providing water services, and the financial analysis of the water and sewer utility funds, the Council had determined that the new rates for the services provided below are reasonable and justified and are hereby approved as set forth below.

Bimonthly Temporary Construction Water Service Charge ( Potable W ter) Meter October 1, 2019 January 1, 2020 Januaia 1, 2021 January 1, 2022 January IL, 2023 110
100. 18 $ 110. 45 $ 121. 77 $ 134. 25 $ 143. 65 Y" 590- 91 $ 651. 48 $ 718. 25 $ 791. 87 $ 847. 31 Temporary Construction Water Commodity RateStructure,(Potable Water) Water Use October 1, 2019 January 1, 2020 January 1, 2021 January 1, 2022 January 1, 2023 Tiers Cost per CCF Cost per CCF Cost ee r CCF Cost per CCF Cost per CCF 1 1- 13 Units 1. 77 $ 1. 95 $ 2. 15 $ 2- 37 $ 2. 54 2 14- 35 Units 2. 24 $ 2. 47 2. 72 3. 00 3. 21
3 36 Units and Cher $ 2. 36 $ 2. 60 2. 87 $ 3. 16 $ 3,381 Imported Water
IConservation Charge $ Ls
BimonthlyTempo TvConstruction WaterService Charge (RecycledWater) Meter October 1, 2019 January 1, 2020Janua 1, 20121 Jana ar 1, 2022 Januaryr 1, 2023

20. 22. 24. 35 26.85 28. 73
T1
118. 18 $ 1 x. 30 143. 65 $ 158. 37 $ 169. 46
TemporaryConstructionWaterComm dity RateStructure (RecycledWater) Water U!se October 1, 2019 January 1, 2020 Janua 1, 2021 January 1, 2022 Janua 1, 2023 Cost er CCF ICost e CCF Coast er CCF Cost per CCF ICostperCCF CCFUnits 1. 301 $ 1. 35 $ 1. 2.6 $ 1. 39 $ 1.35 Contractorsshall provide a refundabledepositfor constructionmetersat the ratesshown below. additionally, theCityshallcollectanadvancepaymentequaltotherateof a singlebimonthly service chargeat the requestedmeter size and type of water to be utilized and 55 CCF at the then current rate, said deposit and advancepaymentis to guaranteepayment for all water usedand. return of the meter. Lost, stolen or damaged meters are the responsibility of the contractor and will be repaired or replaced at the determination of the City.

Deposit amount-
1 Inch Meter- $ 288. 0101
3 Inch Meter- ,$ 1,0131.0101
SECTION 3. The water rates and service charges amended by this five- year rate adjustment plan will resume annual. CPI adjustment, effective January 1" of each year, as outlinedin City CodeSection62-271, startingonJanuary1, 20124.

SECTION 4. TheCity shallbill recycledwatercustomerswhoareresellingCitywater, orutilizingrecycledwateroutsidetheareaservedbytheCity, basedonthefollowingcriteria:

Phase 1. When there is sufficient recycled water , available to meet needs of recycled water customerswithin the areaservedby the City, the City will chane the City"s ratesthenin effectfor retail recycledwaterservicebasedon the meter size and recycled waster consumption.

Phase It. When recycled water is insufficient to meet the needs of the City' s retail recycled water customers, and the City is required to supplement the recycled water systemby adding potable water to the recycled water system to meet recycled water demands, the City' s Tier 3 ratesthen in effect for potable water service charges will be charged for the potable water added to the .recycled water system and sold outside of the area served by the City.

To determinethebilling for theamountof potablewaterused, the City will usethe following criteria.

When potable water is added to the recycled water system to meet wholesale demands, the City will sum all wholesale meter consumptions and subtract the potable water added, giving the volume recycled water provided to the system. The recycled water volume will then be divided by the number of wholesale customers, and subtracted from their wholesale meter read volurne, thereby providing the portion of potable water addedto the system. to meet their demands. Once this is determined, the City will invoice each customer for their portion of recycled water and potable water at the appropriate current rate.

If the total wholesale billings is less than the potable water delivered to the recycledwatersystemin a billing cycle, customerswill be billed at thethen current tier 3 potable water rate for all water used.
11' a wholesale customer does not fully use their portion of recycled water perbillingcycle, theunusedrecycledwaterwill beevenlydistributedto the other wholesale recycled water customers.

Phase 111. 11" the Water Resources Department determines, that there is insufficient recycled water for wholesale use, based on the City' s inability to obtain enoughrecycledwater to keep up with systemdemands, the Department shall notify impactedcustomersas soonas possibleand discontinue providing said recycled water. Once recycled water becomes available, customers shall be notified and sales shall resume as the Department is able to do so, at the then current rate.

SECTION 5. The fees and charges set forth herein shall become effective on October 1, 2019, and shall be adjusted as set forth in Sections 2 and 3 hereof. All resolutions or administrative actions by the City Council, or parts thereof that are inconsistent with any provisionof thisResolutionareherebysupersededonlytotheextentof suchinconsistency.

SECTION 6. The City Clerk shall attestandcertify to thepassageand adoptionof this Resolution.

PASSED, APPROVED AND ADOPTED this 16' h
dayof September, 2019.

CITY OF POMONA:

Tijad0 d` val
Mayor
APPROVED AS TO FORM: ATTEST.
e.. "
w
s
m... .... _
Soria Carvalho ...._.___ .._..._, _ R s.alia A. Butle ,,, Ml'~ lC City Attorney City Clerk
1, HEREBYCERTIFYthattheforegoingresolutionwasdulyadoptedby theCityCouncilof the CityofPomonaataregularmeetingthereofheldonSeptember16, 2019bythefollowingvote of the Council:

AYES: Garcia, Gonzalez, Lustro, Ontiveros-Cole, Preciado, Torres, Sandoval NOES: None
ABSTAIN: None
ABSENT: None
s'
w q
d
Rosana A. But er, 1v1MC
City Clerk

EXECUTIVE ORDER
Thefeessetby ResolutionNo. 2019-128havebeensetin compliancewith Division5 of Chapter2 of the PomonaCity Codepertaining to the fixing of regulatory feesand service charges. Pursuant, to Section 2- 924( d) of the PomonaCity Code, the fee scheduleset by Resolution No. 2019-128 shall take effect ten (10) daysafter the signing of an Executive Order if no written appeal has been filed.

Date:
or rim , val