Calistoga City Council
October 6, 2026

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
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Appendix A. Analysis Methodology
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A GIS-based vulnerability assessment was conducted for each of the priority hazards identified by the Planning Committee. Several sources of data are necessary to conduct a vulnerability analysis. This appendix presents an outline of the data inputs, processing steps, and outputs used to create the vulnerability analysis results presented in the Hazard Mitigation Plan. The analysis methodology is presented first, followed by an overview of the analysis data.

A.1. Natural Hazard Exposure
The natural hazard exposure analysis (see C. Natural Hazard Exposure in Figure A- 2) is an inventory of population, parcels, critical facilities, and other assets within each natural hazard area. As shown in Figure A- 1 the presence of a structure inside a natural hazard area (the flood zone in this example) qualifies that structure as exposed to the natural hazard.

Figure A- 1: Hazard Exposure
The total counts of parcels, people, facilities, assets and the sum of values within the planning area which could be exposed to a hazard event is referred to as the “exposure” in this plan. A natural hazards overlay was developed to reflect the combination of many known natural hazard spatial footprints. The spatial overlay method enables summarization of building values, parcel counts, population exposure, and critical facility exposure within a hazard’s geographic extents (see C. Natural Hazard Exposure in Figure A- 2). The input data is used to evaluate exposure for earthquakes, landslides, flooding, dam inundation, wildfire and sea level rise.

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A.2. Analysis Data
A.2.1. Assets, Value, and Population
A.2.1.1. Parcels
Parcel and address point GIS data supplemented by the county’s assessor roll for important attributes such as building square footage and use code type were used to create a composite data set representing a detailed inventory of building location, values, and construction types countywide. A value of $425/sqft was used as an estimate for building replacement cost. Special precautions were taken to avoid duplicating costs where multiple addresses were represented per parcel. Parcels that had no address points but did have values representative of improvements (buildings) where converted into centroid point locations and merged with the address points for use in analysis. There were a few instances with overlapping polygons in the parcels dataset that required those address points to be removed and centroids used in their place to avoid compounding values.

A.2.1.2. Asset Insurance Schedules
Asset insurance tables provided by the county were geocoded in GIS and used to supplement the critical infrastructure data. These data are referred to as “Real Property Assets” within this plan.

A.2.1.3. Population
Population estimates were derived from 5 year 2022 Census American Community Survey (ACS) estimates as applied to census block groups and then processed through GIS modeling in order to break down the proportional population for smaller units of area.

A.2.1.4. Critical Infrastructure
Critical facilities and transportation/lifeline typically include hospitals, fire stations, police stations, storage of critical records, and similar facilities. These data came from a collection of sources including but not limited to: Napa County GIS, Napa County insurance data, participating jurisdictions, California Department of Social Services (CDSS), California Energy Commission (CEC), Federal Communications Commission (FCC), United States Army Corps of Engineers (USACE), and FEMA. All data sources have a level of accuracy acceptable for planning purposes. See Table A-1 for a complete list of Critical Infrastructure data and sources used in the analysis.

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A.2.2. Natural Hazard Data
A.2.2.1. Dam Inundation Zones
Dam inundation zone GIS data were provided by California Department of Water Resources. These represent the estimated flood extent in the event of dam failure for individual dams.

Hazard Description
Inundation Area
Dam Inundation maps for the State of California are required by California Government Code Section 8589.5(b). DWR Dam Breach Inundation studies are used for inundation sourcing for dams with detailed boundaries.

Source: DWR
A.2.2.2. Earthquake Shaking
The CGS 2% chance/50-year probability map was used as a qualitative guide in selecting an earthquake epicenter-based ShakeMap scenario for analyses. The M6.7 West Napa and M7.1 Hunting Creek Berryessa earthquake scenarios were used in this plan’s GIS analyses.

Intensity MMI Description/Damage
I-Not felt 0-1 Not felt except by a very few under especially favorable conditions.

II-Weak 1-2 Felt only by a few persons at rest, especially on upper floors of buildings.

III-Weak 2-3
Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated.

IV-Light 3-4
Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound.

Sensation like heavy truck striking building. Standing motor cars rocked noticeably.

V-Moderate 4-5
Felt by nearly everyone; many awakened. Some dishes, windows broken.

Unstable objects overturned. Pendulum clocks may stop.

VI-Strong 5-6
Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.

VII-Very strong 6-7
Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.

VIII-Severe 7-8
Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.

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Intensity MMI Description/Damage
IX-Violent 8-9
Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations.

X-Extreme 9-10 Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent.

Source: USGS Scenario MMI Grid
A.2.2.3. Liquefaction
Hazard Native Class Description
Liquefaction Zone Yes
Where the stability of foundation soils must be investigated, and countermeasures undertaken in the design and construction of buildings for human occupancy.

Source: Napa County Liquefaction Susceptibility
A.2.2.4. Flood Zones
FEMA regulatory flood plain GIS data was used as the basis of the flood hazard. The most recent and active Digital Flood Insurance Rate Map (DFIRM) / National Flood Hazard Layer (NFHL) was obtained from FEMA at the start of this project’s analysis and utilized in this plan’s GIS analyses.

Hazard Flood Zone Description
100-YR Flood
[SFHA]
Subtype: Floodway
A "Regulatory Floodway" means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height. Communities must regulate development in these floodways to ensure that there are no increases in upstream flood elevations.

SFHA outside
Floodway
The land area covered by the floodwaters of the base flood is the Special Flood Hazard Area (SFHA) on NFIP maps. The SFHA is the area where the National Flood Insurance Program's (NFIP's) floodplain management regulations must be enforced and the area where the mandatory purchase of flood insurance applies.
500-YR Flood
[non-SFHA]
Subtypes: 0.2%
Annual Chance,
Protected by Levee
Moderate risk areas within the 0.2-percent-annual-chance floodplain, areas of 1-percent-annual-chance flooding where average depths are less than 1 foot, areas of 1-percent-annual-chance flooding where the contributing drainage area is less than 1 square mile, and areas protected from the 1- percent-annual-chance flood by a levee. No BFEs or base flood depths are shown within these zones.

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Protected by Levee
[non-SFHA] Protected by Levee Areas protected from the 1-percent-annual-chance flood by a levee. No BFEs or base flood depths are shown within these zones.

Source: FEMA MSC DFIRM
A.2.2.5. Slope Failure
California Geological Society deep seated landslide raster data were reclassified and converted into polygons based on the reclassification schema below.

Hazard Native Class Description
Low 1-5
These classes express the generalization that on very low slopes, landslide susceptibility is low even in weak materials, and that landslide susceptibility increases with slope and in weaker rocks.

Medium 6-7
Very high landslide susceptibility, classes VIII, IX, and X, includes moderate and steep slopes in hard rocks and weak rocks.

High* 8-10 Very high landslide susceptibility, classes VIII, IX, and X, includes very steep slopes in hard rocks and moderate to very steep slopes in weak rocks.

Source: CGS Susceptibility to Deep-Seated Landslides in California A.2.2.6. Sea Level Rise
Hazard Native Class Description
MHHW 0
Data represents potential inundation from sea level rise from Mean High Water (MHHW) to 6 feet above MHHW in the year 2100. Inundation areas were created by NOAA Coastal Services Center (CSC) and defined using a modified bathtub approach.
1ft 1
2ft 2
3ft 3
4ft 4
5ft 5
6ft 6
Source: National Oceanic and Atmospheric Administration Coastal Services Center. Accessed via ABAG CAL OES SUBMITTAL - JUNE 2026
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A.2.2.7. Wildfire Hazard Severity Zones
Hazard Native Class Description
Moderate Moderate
(LRA & SRA)
Classification of a zone as moderate, high or very high fire hazard is based on a combination of how a fire will behave and the probability of flames and embers threatening buildings. "This data represents Fire Hazard Severity Zones (FHSZ) in the State Responsibility Area (SRA), effective April 1st 2024, and recommended Fire Hazard Severity Zones in the Local Responsibility Area (LRA) from 2007-2011. It also represents Fire Hazard Severity Zones originally adopted in SRA that have since been reclassified as LRA." - California Department of Forestry and Fire Protection. Accessed June 2024.
*Additionally - The Draft LRA delineations as modified and proposed by the County were utilized in all areas covered by the LRA Delineations. Outside of these areas, the authoritative April 2024 SRA's were leveraged.

High High
(LRA & SRA)
Very High Very High
(LRA & SRA)
Source: CalFire & Napa County.

A.2.2.8. Wind Classification
Wind is classified by the National Renewable Energy Laboratory (NREL) based on average speeds across the ground at different elevations in meters per second (m/s) and the amount of power it is capable of producing (wind power density). Power density is measured in the amount of watts (W) that can be produced per square meter (m2) of surface area on the blades of a wind turbine.

Wind
Power
Class
10 m (33 ft) 50 m (164 feet)1
Wind Power Density
W/m2
Mean Speed2
m/s (mph)
Wind Power Density
W/m2
Mean Speed2
m/s (mph)
1 ≤ 100 4.4 (9.8) ≤ 200 5.6 (12.5)
2 100-150 5.1 (11.5) 200-300 6.4 (14.3)
3 150-200 5.6 (12.5) 300-400 7.0 (15.7)
4 200-250 6.0 (13.4) 400-500 7.5 (16.8)
5 250-300 6.4 (14.3) 500-600 8.0 (17.9)
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6 300-400 7.0 (15.7) 600-800 8.8 (19.7)
7 >400 9.4 (21.1) >800 11.9 (26.6)
Notes:
1Vertical extrapolation of wind speed based on the 1/7 power law. 2Mean wind speed is based on Rayleigh speed distribution of equivalent mean wind power density and is for standard sea level conditions.

Source: NREL, 2007
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A.2.3. Methodology Overview
Figure A- 2: Data Analysis Methodology
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A.2.4. Data Dictionary
Table A-1: Data Dictionary
Dataset Data Steward Notes
Jurisdictional/Municipal Boundaries County County Arc GIS Hub Napa County Office of Education Boundary County Countywide Stream NHD New NHD Plus
Water NHD New NHD Plus
Building Outlines OSM OSM Data - Used in some cartographic products only.

Parcel Geometry County County Arc GIS Hub
Parcel Roll County County Assessor's Office
Emergency Operations Center County Manual Placement
Fire Station County 2024 County Data Request GDB
Hospital County 2024 County Data Request GDB
Law Enforcement County 2024 County Data Request GDB
Adult Res Facility CDSS CDSS From 2018 plan
Child Care Center CDSS CDSS From 2018 plan
Church County County GIS from 2018 plan
Communication Tower FCC FCC From 2018 plan
Real Property Assets County
Insurance property schedule with
appraisal values, building characteristics,
and location.

Dam USACE NID, DWR
3rd party source data can be
supplemented by local data per
availability.

Emergency Shelter County 2024 County Data Request GDB
Family Child Care Home CDSS CDSS From 2018 plan
Farm Worker Housing County County GIS from 2018 plan
Historic Building NPS NPS From 2018 plan
Home Care Organization County County GIS from 2018 plan Library County County GIS from 2018 plan
Medical Office County From Legacy 2013 plan data. Only
available data.

Mobile Home Park County County GIS from 2018 plan
Res Elder Care Facility CDSS CDSS From 2018 plan
School CDE Broken out into two separate layers one
for private and another for public
Airport County County GIS from 2018 plan
Bridge NBI National bridge inventory
Bus Stop NVTA From arcgis feature service
Levee FEMA NFHL 2018
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Levee Centerline USACE NLD May be depricated by NLD WFS 2018 Levee Flood Wall USACE NLD NLD WFS 2018
NG Pipeline CEC From legacy CEC data
NG Station CEC From legacy CEC data
Power Plant CEC CEC from 2018 plan
Railroad Esri Legacy Esri data.

Street OSM OSM OSM Data pull includes highways and
local roads
Substation CEC California Energy Commission
Bus_Route NVTA Only included within Napa County
HMMWC_Asset HMMWC, DPS 2018 Data development for Howell Mountain Mutual Water Company
HMMWC_Dam HMMWC, DPS 2019 Data development for Howell
Mountain Mutual Water Company
HMMWC_Hydrant HMMWC, DPS 2020 Data development for Howell Mountain Mutual Water Company
HMMWC_Pipeline HMMWC, DPS 2021 Data development for Howell Mountain Mutual Water Company
Recycled_Water_Mains NapaSan 2024 Data Request
Sewer_Gravity_Mains NapaSan 2024 Data Request
Water_Supply_Intake County 2024 County Data Request GDB Water_Tank County 2024 County Data Request GDB
Transmission Line CEC California Energy Commission
Wastewater Treatment Facility County Includes ownership information for NapaSan
Water Treatment Facility County 2024 County Data Request GDB Geotracker CleanupSite Geotracker Geotracker cleanup sites active HWTS Active Facility DTSC Hazardous Waste Tracking System Active Facilities
Landfill County County GIS from 2018 plan
Census Block Group US Census Bureau 2022 ACS
Dam Inundation DWR
DWR covers all dams included in legacy
Cal OES data as well as additional studies.

More than 70 dams in county
EQ Scenarios 1-X USGS, CISN Chosen qualitatively from shake potential map
Flood Hazard FEMA 06055C Obtained July 2024
Landslide Susceptibility CGS Classified and post-processed by DPS Sea Level Rise ABAG ABAG SLR Inundation data from 2018
plan. Metadata describes NOAA.

Shake Potential USGS, CISN Used to illustrate scenario risk Wildfire Hazard Severity Zone CalFire
Modified Draft LRAs from 2025 and New
2024 data that includes combined SRA
and LRA FHSZ.

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B
Appendix B. Process Documentation
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Planning Process Documentation Appendix
Table of Contents
Planning Committee Meeting Documentation.............................................. B.1-1 Jurisdictional Breakout Meetings.................................................................. B.1-39 Public Notice & Press Release Documentation..............................................B.2-1 Survey & Results Documentation.......................................................................B.3-1 Mitigation Strategy Prioritization Process Documentation......................B.4-1 Website Documentation ........................................................................................B.5-1 Outreach Events.......................................................................................................B.6-1 CAL OES SUBMITTAL - JUNE 2026
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Planning
Committee Meeting
Documentation
Appendix B.1
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BO 1 Napa City Zoom
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BO 1 NCFCWD Zoom
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BO 1 Yountville Zoom
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BO 2 Calistoga Zoom
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BO 2 Napa San Zoom
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BO 2 NCFCWD Zoom
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BO 2 St Helena Zoom
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BO 2 Yountville Zoom
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Kick Off Agenda
Meeting Agenda:

Napa County, California
Mulit-Jurisdictional Hazard Mitigation Plan 2024 Update Kick-Off Meeting Wednesday, February 28, 2024, 1:00 p.m. – 2:00 p.m.

Meeting Objectives
 Welcome and Introductions
 Scope of Work Review
 Participant Expectations
 Local Hazard Mitigation Planning Process
 Project Schedule
 Next Steps
NOTES
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Kick Off Sign In 1
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Kick Off Sign In 2
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Kick Off Zoom Attendance
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PC 1 Agenda 1
Meeting Agenda:

Napa County, California
Multi-Jurisdictional Hazard Mitigation Plan 2024 Update Large Stakeholder Meeting #1
Tuesday, May 7th, 2024, 9:00 a.m. – 11:00 a.m.

Meeting Objectives
 Executive Overview
 Welcome and
Introductions
 Polling Icebreakers
 Background & Mitigation
101
 The Planning Process
 Project Schedule
 Website Review
 Hazard Mitigation Funding
Opportunities
 2019 HMP Review & Discussion
 Recent Success Stories
 What’s Changed
 Outreach
NOTES
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PC 1 Agenda 2
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PC 1 In Person
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PC 1 Zoom Screenshot 1
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PC 1 Zoom Screenshot 2
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PC1 Sign In Scan
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PC 2 Agenda 1
Meeting Agenda:

Napa County, California
Multi-Jurisdictional Hazard Mitigation Plan 2024 Update Large Stakeholder Meeting #2
July 18th, 2024, 10:00 a.m. – 12:00 p.m.

Meeting Objectives
▪ Welcome and Introductions
▪ Meeting # 1 recap
▪ Risk Assessment / Community
Vulnerability Review
▪ Demographics & Vulnerable
Populations
▪ Abbreviated Hazard Profiles
▪ Complete Risk Matrix Exercise
Important Links
Project Webpage:
mitigatehazards.com/napacountymjhmp/
Website Username/Password:

Napa2024
Meeting Polling:
www.pollev.com/dynamicplanning
▪ Discuss Areas of Concern (AOC’s)
▪ Preview Risk Assessment
Mapping Platform (RAMP)
▪ Review Outreach Progress & Next
Steps
Pollev:

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PC 2 Agenda 2
NOTES:

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PC2 Handout 1-answers
Napa County’s RAMP Quiz Bowl!

1. What is the estimated population
in Unincorporated Napa County
living within the Landslide
Hazard?
6,178

2. What is the estimated population
within the City of Napa living
within Dam Inundation Zones?
12,963

3. What is the estimated population
within the City of Calistoga living
within the 100-year flood zone?
990

4. County wide, how many parcels are
identified within very-high wildfire
severity zones?
4,085

5. County wide, how much property
value is exposed within the 100-
year floodplain?
$1,441,320,455

6. County wide, how much property
value is exposed within both the
very high wildfire hazard and
landslide risk? (Hint: use two
property filters to answer this
question!)
$1,002,492,743

7. How many miles of lifeline are in
the very strong shake zone from
the M6.7 West Napa Scenario?
1,000 mi

8. How many Fire stations (“Fire”) are
in the very strong shake zone from
the M7.1 Hunting Creek Berryessa
Scenario? Bonus Point: What is the
address of one of them?
13 9. County wide, how many of the
following types of facilities are
located within a very high wildfire
severity zone:

Child Care Center 4
Mobile Home Park 5
Hospital 1
Real Property Asset 81
Water Treatment
Facility
3 10. How many Residential Elder Care
Facility are located within the City of
Napa 100-yr flood risk layer?
2 11. How many bridge points are located
within the Unincorporated Napa
County flood risk layer? 58

12. What are the names of one of the
HWTS facilities located within the
City of St. Helena’s flood risk layer?
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PC2 Handout 1
Napa County’s RAMP Quiz Bowl!
Instructions
Risk Assessment Mapping Platform (RAMP) was developed to provide stakeholders with an interactive way to explore the County’s natural hazard risk landscape. The following quiz will test your ability to use RAMP to answer real-world questions about the exposure of population, parcels, and critical infrastructure to hazards like earthquake, landslide, dam failure, and more.

Navigate to https://mitigatehazards.com/Napa24/RAMP/#/ to access the web platform.

FINAL SCORE: out of 10

1. What is the estimated population in
Unincorporated Napa County living
within the Landslide Hazard?

2. What is the estimated population
within the City of Napa living within
Dam Inundation Zones?

3. What is the estimated population
within the City of Calistoga living
within the 100-year flood zone?

4. County wide, how many parcels are
identified within very-high wildfire
severity zones?

5. County wide, how much property
value is exposed within the 100-year
floodplain?

6. County wide, how much property
value is exposed within both the
very high wildfire hazard and
landslide risk? (Hint: use two
property filters to answer this
question!)

7. How many miles of lifeline are in
the very strong shake zone from the
M6.7 West Napa Scenario?

8. How many Fire stations (“Fire”) are in
the very strong shake zone from the
M7.1 Hunting Creek Berryessa
Scenario? Bonus Point: What is the
address of one of them?

9. County wide, how many of the
following types of facilities are
located within a very high wildfire
severity zone:

Child Care Center
Mobile Home Park
Hospital
Real Property Asset
Water Treatment
Facility

10. How many Residential Elder Care
Facility are located within the City of
Napa 100-yr flood risk layer?

11. How many bridge points are located
within the Unincorporated Napa
County flood risk layer?

12. What are the names of one of the
HWTS facilities located within the
City of St. Helena’s flood risk layer?
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-27
PC2 SignIn Scan (1)
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-28
PC2 SignIn Scan (2)
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-29
PC2 Zoom Screenshot 1
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-30
PC2 Zoom Screenshot 2
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-31
PC 3 Agenda 1
Meeting Agenda
Napa County, California
Multi-Jurisdictional Hazard Mitigation Plan 2025 Update Large Stakeholder Meeting #3
Tuesday, March 25, 2025, 1:00 p.m. – 3:30 p.m.

Meeting Objectives
▪ Welcome
▪ Project Schedule
▪ Recap/Key Takeaways
▪ Meeting #1 and #2
▪ Breakout Sessions Reviews
▪ Review Changes in Mitigation
Strategies Since 2020
▪ Mitigation Action Exercise
▪ Closeout/Next Steps
▪ Community
Engagement
▪ Schedule Reminders
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-32
PC3 In Person
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-33
PC3 Sign In
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-34
PC3 Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-35
PC 4 Meeting Photo 2
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-36
PC4 Meeting Photo 1
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-37
PC4 Poster Scan
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-38
PC4 Sign In Scan
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-39
Jurisdictional
Breakout Meetings
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

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NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE

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B.1-40
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-41
BO 1 ACFPD Meeting Presentation
Napa County
Hazard Mitigation Plan
2024 Update
American Canyon Fire Protection District Breakout Meeting #1 Wednesday, August 14th, 2024
2:00 P.M. – 4:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-42
BO 1 American Canyon Meeting Slide
Napa County
Hazard Mitigation Plan
2024 Update
City of American Canyon Breakout Meeting #1
Tuesday, October 1st, 2024
9:00 AM – 11:00 AM
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-43
BO 1 American Canyon Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-44
BO 1 Calistoga Meeting Slide
Napa County
Hazard Mitigation Plan
2024 Update
City of Calistoga Breakout Meeting #1
Thursday, August 22nd, 2024
2:00 P.M. – 4:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-45
BO 1 Calistoga Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-46
BO 1 HMMWC Meeting Slide
Napa County
Hazard Mitigation Plan
2024 Update
Howell Mountain Mutual Water Company Breakout Meeting #1 Tuesday, September 10th , 2024
11:00 A.M. – 1:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-47
BO 1 HMMWC Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-48
BO 1 Napa Co Meeting Slide
Napa County
Hazard Mitigation Plan
2024 Update
City of Napa Breakout Meeting #1
Wednesday, September 25th, 2024
1:00 P.M. – 3:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-49
BO 1 Napa Co Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-50
BO 1 Napa San Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-51
BO 1 NapaSan Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-52
BO 1 NCOE Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-53
BO 1 NVC Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-54
BO 1 NVTA Meeting Slide
Napa County
Hazard Mitigation Plan
2024 Update
Napa Valley Transportation Authority Meeting #1
Thursday, September 5th , 2024
12:00 P.M. – 2:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-55
BO 1 NVTA Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-56
BO 1 St Helena Zoom
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-57
BO 1 St. Helena Meeting Slidepdf
Napa County
Hazard Mitigation Plan
2024 Update
City of St. Helena Breakout Meeting #1
Thursday, September 26th , 2024
1100 A.M. – 1:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-58
BO 2 ACFPD Slide
Napa County
Hazard Mitigation Plan
2025 Update
American Canyon FPD
Breakout Meeting #2
Monday June 22, 2025
12:00 – 2:00 PM
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-59
BO 2 American Canyon Slide
Napa County
Hazard Mitigation Plan
2024 Update
City of American Canyon
Breakout Meeting #2
Thursday, January 29, 2026
1:00 – 2:00 PM
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-60
BO 2 HMMWC Slide
Napa County
Hazard Mitigation Plan
2024 Update
Howell Mountain Mutual Water Co.

Break Out Meeting #2
Tuesday, June 3 , 2025
1:00 P.M. – 3:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-61
BO 2 Napa COE Slide
Napa County
Hazard Mitigation Plan
2024 Update
Napa County Office of Education Break Out Meeting #2
Friday, May 8th , 2024
2:00 P.M. – 4:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-62
BO 2 NVC Agenda 1
Jurisdictional Breakout Meeting Series #2 Read-Ahead Packet - Attachment A – Breakout Meeting #2 Details & Agenda Date: Tuesday, August 19, 2025
Time: 10:00A.M. – 12:00 P.M.

Location: Zoom
Meeting ID: 858 7940 4781
Passcode: 482623
Facilitator(s): Dynamic Planning + Science
(DP+S), Ethan Mobley, Christopher Velasco
Breakout Meeting #2 is part of Phase 3, Develop the Mitigation Strategy, which is the most important phase of developing the 2025 Napa County Multi-Jurisdictional Hazard Mitigation Plan (MJHMP). This breakout meeting will focus on taking all the information we’ve previously gathered, discussed, and analyzed, and using it to build an actionable mitigation strategy that addresses the highest priority hazard problems and greatest areas of concern; aligns with community feedback and jurisdictional capabilities; and considers opportunities for multi-jurisdictional collaboration.

At the end of Breakout Meeting #2, participants will:
▪ Understand and Have Consensus on Jurisdictional Capabilities in implementing their unique mitigation strategy to address jurisdiction-specific problems and support regional collaboration (see SECTION 2 and Attachment B).
▪ Understand and Have Consensus on Jurisdictional Problem Statements which describe the area(s) of concern (victim, impact, or threat) for high-priority hazards and specific risks that were identified through the risk assessment process, community feedback, and prioritization exercise from Breakout Meeting #1 (see SECTION 3 and Attachment C). ▪ Understand and Have Consensus on Jurisdictional Mitigation Actions that align with local capabilities, community-driven priorities, and FEMA guidelines; address specific problem statements; follow the SMARTIE guidelines and are cost- and resource-effective; and support inter-agency collaboration (see SECTION 4 and Attachment D).

CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.1-63
BO 2 NVC Agenda 2
Jurisdictional Breakout Meeting Series #2 Read-Ahead Packet - Attachment A – Breakout Meeting #2 Details & Agenda ID Time Action Item Key Decision / Support
Request
1 10 min Welcome & Project Updates
Overview of meeting goals, structure, and expected outcomes, and updates on project timeline.
2 15 min Designing the Mitigation Strategy
Recap of the process and considerations for designing the mitigation strategy, including review of the draft capabilities assessment and SMARTIE principles.

Feedback and consensus
on capabilities assessment
3 30 min Defining the Problem
Overview of areas of concern (AOCs) and review of draft problem statements.

Feedback and consensus
on problem statements
4 5 min Evaluating Mitigation Alternatives
Overview of mitigation alternatives and potential strategies, projects, and activities.
5 55 min Mitigation Strategy Refine & Align Exercise
Interactive group exercise to review draft mitigation actions to align with jurisdictional capabilities and identified problems.

Feedback and consensus
on potential mitigation
actions
6 5 min Next Steps & Closeout
a) Upcoming public outreach events, HMPT Meeting #4
b) Questions and open discussion
Confirm upcoming tasks
and needed follow-up
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.1-64
BO 2 NVTA Slide
Napa County
Hazard Mitigation Plan
2024 Update
Napa Valley Transportation Authority
Break Out Meeting #2
Wednesday, May 7th , 2024
2:00 P.M. – 4:00 P.M.
www.mitigatehazards.com
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.2-1
Public Notice & Press
Release Documentation
Appendix B.2
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE

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B.2-2
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Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.2-3
City Napa Newsetter
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.2-4
Mitigate Banner ReadyNapaCo
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.2-5
Napa County Webpage
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.2-6
NapaSan Facebook Post
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.2-7
St Helena Instagram Post
CAL OES SUBMITTAL - JUNE 2026
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HAZARD MITIGATION PLAN 2026 UPDATE

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NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE

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NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-1
Survey & Results
Documentation
Appendix B.3
CAL OES SUBMITTAL - JUNE 2026
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HAZARD MITIGATION PLAN 2026 UPDATE

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NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE

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Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-3
Napa County Survey Summary
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.3-4
Survey Print Version Napa County 2025 Hazard Mitigation Plan Update Napa County 2025 Hazard Mitigation
Plan Update
Please provide us with your email to be entered into prize drawing. (Optional) Do you live or work in Napa County?
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-5
Survey Print Version Napa County 2025 Hazard Mitigation Plan Update Where do you live and/or own property?
Do you rent or own your home?
What is your age range?
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.3-6
Survey Print Version Napa County 2025 Hazard Mitigation Plan Update How many individuals currently live in your household?
Do you feel well informed about the dangers of natural disasters in this area? In your opinion, how vulnerable do you believe your property/home is to damage from a natural disaster event?
How prepared is your household or business to evacuate during an emergency event?
A.

A.

B.

B.

CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-7
Survey Print Version Napa County 2025 Hazard Mitigation Plan Update Which of the following types of events have you or someone in your household experienced in Napa County in the last 20 years? (Check all that apply)
Rate your perception of how high a threat each hazard below poses to Napa County. (Pick one per row)
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.3-8
Survey Print Version Napa County 2025 Hazard Mitigation Plan Update What actions have you taken for your home or property to reduce risk of damage or injury from potential disasters? (Check all that apply) What kind of insurance policies, if any, do you have to protect your home or property? Check all that apply.

CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-9
Survey Print Version Napa County 2025 Hazard Mitigation Plan Update How confident do you feel about your financial preparedness to handle unexpected expenses during a disaster or emergency situation? What barriers, if any, do you face in taking action to reduce your property's risk to natural hazards/disasters? Check all that apply.

Which of the following incentives would encourage you to protect your home to withstand the impacts of possible hazards? (Check all that apply) CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.3-10
Survey Print Version Napa County 2025 Hazard Mitigation Plan Update Which of the following actions do you believe the County should focus on to reduce disruption of services, increase safety, and strengthen the community? (Check all that apply)
Thank you again for completing the survey! Please provide any additional questions, comments, or concerns that you may have regarding hazard mitigation and community protection against disasters.

CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-11
Survey Print Version Spanish Napa County 2025 Hazard Mitigation Plan Update Actualización del Plan de Mitigación de
Riesgos del Condado de Napa 2025
Por favor complete todas las preguntas de la encuesta completamente. Gracias por su participación.
¿Dónde vive y/o povecinasee propiedad?
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.3-12
Survey Print Version Spanish Napa County 2025 Hazard Mitigation Plan Update ¿Usted renta o posee su propio hogar?
¿Cuál es su rango de edad?
¿Cuántas personas viven actualmente en su hogar?
¿Te sientes bien informado sobre los peligros de los desastres naturales en esta área?
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-13
Survey Print Version Spanish Napa County 2025 Hazard Mitigation Plan Update En tu opinión, ¿qué tan vulnerable crees que es tu propiedad/casa al daño por un evento de desastre natural?
¿Qué tan preparado está tu hogar o negocio para evacuar durante un evento de emergencia?
Califica en la escala del 1 al 5:
¿Qué tipo de eventos has experimentado tú o alguien en tu hogar en el condado de Napa en los últimos 20 años? (Marca todas las que apliquen) A.

B.

A. B.

CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.3-14
Survey Print Version Spanish Napa County 2025 Hazard Mitigation Plan Update Evalúa tu percepción sobre cuán alta es la amenaza que representa cada uno de los peligros a continuación para el condado de Napa. ( Elija uno por fila y califique en la escala del 1 al 5)
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-15
Survey Print Version Spanish Napa County 2025 Hazard Mitigation Plan Update ¿Qué acciones has tomado para tu hogar o propiedad para reducir el riesgo de daño o lesión por desastres potenciales? (Marca todas las que apliquen) ¿Qué tipo de pólizas de seguro, si las hay, tienes para proteger tu hogar o propiedad? Marca todas las que apliquen.

CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

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NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
B.3-16
Survey Print Version Spanish Napa County 2025 Hazard Mitigation Plan Update ¿Qué tan seguro te sientes sobre tu preparación financiera para manejar gastos inesperados durante un desastre o situación de emergencia? ¿Qué barreras, si las hay, enfrenta para tomar medidas para reducir el riesgo de su propiedad ante desastres/naturales? Marque todas las que correspondan. ¿Cuál de los siguientes incentivos lo alentaría a proteger su hogar para resistir los impactos de posibles peligros? (Marque todos los que correspondan) CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.3-17
Survey Print Version Spanish Napa County 2025 Hazard Mitigation Plan Update ¿En cuáles de las siguientes acciones cree que las agencias públicas en el Condado de Napa deberían centrarse para reducir la interrupción de los servicios, aumentar la seguridad y fortalecer la comunidad? (Marque todas las que correspondan)
¡Gracias nuevamente por completar la encuesta! Proporcione cualquier pregunta, comentario o inquietud adicional que pueda tener sobre la mitigación de peligros y la protección comunitaria contra desastres.

CAL OES SUBMITTAL - JUNE 2026
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NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE

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CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE
HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
B.4-1
Mitigation Strategy
Prioritization Process
Documentation
Appendix B.4
CAL OES SUBMITTAL - JUNE 2026
Item #6.5.

HAZARD MITIGATION PLAN 2026 UPDATE

NAPA COUNTY
NAPA COUNTY | HAZARD MITIGATION PLAN 2026 UPDATE

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Website Documentation
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Outreach Events
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Multi-Jurisdictional Hazard
Mitigation Plan Update
VOLUME 2

JURISDICTIONAL ANNEXES

BACK TO MAIN TABLE OF CONTENTS
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Napa County
Multi-Jurisdictional Hazard Mitigation Plan Update
2026
Volume 2: Jurisdiction-Specific Annexes ..

Introduction ...................................................................................................................................................iv Section 1. City of American Canyon....................................................................................................... 1-1 Section 2. City of Calistoga.......................................................................................................................2-1 Section 3. City of Napa ..............................................................................................................................3-1 Section 4. City of St. Helena.....................................................................................................................4-1 Section 5. Town of Yountville..................................................................................................................5-1 Section 6. American Canyon Fire Protection District.......................................................................6-1 Section 7. Howell Mountain Mutual Water Company.......................................................................7-1 Section 8. Napa County Flood Control and Water Conservation District.....................................8-1 Section 9. Napa County Office of Education........................................................................................9-1 Section 10. Napa Valley College ............................................................................................................10-1 Section 11. Napa Valley Transportation Authority............................................................................11-1 Section 12. Napa Sanitation District.................................................................................................... 12-1 CAL OES SUBMITTAL - JUNE 2026
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Introduction
Volume 2 presents the jurisdictional annexes for all participating jurisdictions in the Napa County MultiJurisdictional Hazard Mitigation Plan (MJHMP) and documents the process used to develop them. In the context of hazard mitigation planning, a participating jurisdiction includes local governments such as cities, towns, special districts, and other public entities that engage in the planning process and contribute to the development and implementation of mitigation strategies to reduce risk from natural hazards.

To meet FEMA requirements for multi-jurisdictional plans, each participating jurisdiction must demonstrate active involvement in the planning process and formal adoption of the plan. Volume 2 provides documentation of this participation and compliance.

Volume 1 serves as the umbrella plan and provides detailed methodology, including stakeholder and public outreach, data collection, and plan development. Volume 2 builds on this foundation by providing jurisdiction-specific annexes that include hazard identification, vulnerability assessments, and mitigation strategies tailored to each participating jurisdiction. Participating jurisdictions also contributed data, technical input, and review of Volume 1.

Each annex in Volume 2 is provided as a standalone, hyperlinked document to facilitate ease of access and use by individual jurisdictions. Volume 2 is intended to support participating jurisdictions in accessing and implementing their annex-specific mitigation strategies.

Following approval by Cal OES and FEMA, participating jurisdictions are eligible to apply for funding through FEMA’s Hazard Mitigation Assistance (HMA) programs, including the Hazard Mitigation Grant Program (HMGP), Flood Mitigation Assistance (FMA), and Building Resilient Infrastructure and Communities (BRIC). Additional information on these programs is provided in Volume 1, Section 4.2.3.

All FEMA approvals and jurisdictional adoption resolutions are available through the project website:

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Planning Process Library
All participating jurisdictions crafted their own annex, complete with a hazard identification and risk assessment, vulnerability assessment, problem statements, mitigation strategy, and capabilities assessment, by following the Planning Process outlined in Volume 1, Section 2.1.3 (Table 1). This section provides links to these specific tasks that lead to the development of the annex, as well as the fully produced annex document. Each subsection includes a crosswalk of tasks completed by each participating jurisdiction and the status of progress made towards submission and approval of the annexes by Cal OES and FEMA.

Table 1: Planning Process Library
Exercise No. / Title Library Links
1 Risk Assessment Hazard and Demographic Maps
2 Hazard Prioritization Risk Matrices
3 Areas of Concern Problem Statements
4 Capabilities and Opportunities Assessment Assessments 5 Strategy Development Alternatives Considered (see Action Plans for final Strategies)
Municipal Jurisdictions
Municipalities, to include both cities and towns, hold the most extensive authority, financial resources, and services among participating jurisdictions. In California, this power is derived from Article XI, § 7 of the state constitution, granting them the ability to enact local laws, manage public works, utilities, and oversee municipal property and finances.

Municipalities can be charter or general law cities, with charter cities having greater autonomy over municipal affairs, as outlined in Article XI, § 5(a). Regardless of type, municipalities have significant authority, particularly in mitigating hazards. (League of California Cities) Table 2 includes a listing of each jurisdiction-specific breakout meeting including meeting dates and topics.

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Table 2: Municipality Meetings Summary
Breakout Meeting #1 (BO #1)
Summary of Topics
Breakout Meeting #2 (BO #2)
Summary of Topics
Purpose: To introduce jurisdiction-specific hazard
mitigation planning efforts, present risk assessment
findings, and support initial prioritization of hazard
risks using countywide data and planning tools.

Breakout Meeting #1 focused on introducing key
planning inputs, reviewing countywide coordination
efforts, and presenting jurisdiction-specific risk
assessment findings and tools. Topics included:
• Recaps of Countywide HMPT Meetings #1 and
#2 (or #1 through #3, as applicable)
• Community engagement progress and results
• Risk assessment findings and community
vulnerability
• Demographics and identification of
vulnerable populations
• Overview of jurisdiction-specific hazard risks
and exposure
• Introduction to the Risk Assessment Mapping
Platform (RAMP)
• Jurisdiction-specific hazard risk ranking
exercise
• Project schedule updates and next steps
Purpose: To refine mitigation strategies and develop
jurisdiction-specific actions by building on identified risks, capabilities, and community input.

Breakout Meeting #2 focused on refining mitigation
strategies and aligning jurisdiction-specific actions
based on identified risks and capabilities. Topics
included:
• Recap of Breakout Meeting #1 and HMPT
Meeting #3
• Review of the capabilities assessment
• Identification of areas of concern and
development of problem statements
• Principles of effective mitigation strategies
and evaluation of alternatives
• Refinement and alignment of jurisdictionspecific mitigation actions • Project schedule updates and next steps
BO #1 Meeting Dates by Jurisdiction:
• City of American Canyon – October 1, 2024
• City of Calistoga – August 22, 2024
• City of Napa – September 25, 2025
• City of St. Helena – September 26, 2024
• Town of Yountville – November 6, 2025
BO #2 Meeting Dates by Jurisdiction:
• City of American Canyon – January 29, 2026
• City of Calistoga – November 10, 2025
• City of Napa – June 12, 2025
• City of St. Helena – June 18, 2025
• Town of Yountville – November 19, 2025
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Special Districts
Special districts participating in the Napa County Multi-Jurisdictional Hazard Mitigation Plan (MJHMP) play a critical role in delivering essential services and maintaining infrastructure vital to community resilience. As limited-purpose entities established under California law, they provide services such as fire protection, water, wastewater, flood control, education, and transportation. While their authority is more narrowly defined than that of cities or counties, special districts oversee key facilities and systems that are often directly exposed to hazards and are essential for response and recovery.

Table 3 includes a listing of each jurisdiction-specific breakout meeting including meeting dates and topics.

Table 3: Special District Meetings Summary
Breakout Meeting #1 (BO #1)
Summary of Topics
Breakout Meeting #2 (BO #2)
Summary of Topics
Purpose: To introduce special district participation in the hazard mitigation planning process, present risk
assessment findings, and support initial
prioritization of hazard risks based on district
operations, assets, and service responsibilities.

Breakout Meeting #1 focused on introducing key
planning inputs, reviewing countywide coordination
efforts, and presenting district-specific risk
assessment findings and tools. Topics included:
• Recaps of Countywide HMPT Meetings #1 and
#2
• Community engagement progress and results
• Risk assessment findings and community
vulnerability
• Demographics and identification of
vulnerable populations
• Overview of district-specific hazard risks and
exposure
• Introduction to the Risk Assessment Mapping
Platform (RAMP)
• Jurisdiction-specific hazard risk ranking
exercise
• Project schedule updates and next steps
Purpose: To refine mitigation strategies and develop
district-specific actions by building on identified
risks, capabilities, and operational priorities.

Breakout Meeting #2 focused on refining mitigation
strategies and aligning district-specific actions based on identified risks, infrastructure vulnerabilities, and service delivery considerations. Topics included:
• Recap of Breakout Meeting #1 and HMPT
Meeting #3
• Review of the capabilities assessment
• Identification of areas of concern and
development of problem statements
• Principles of effective mitigation strategies
and evaluation of alternatives
• Refinement and alignment of jurisdictionspecific mitigation actions • Project schedule updates and next steps
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Breakout Meeting #1 (BO #1)
Summary of Topics
Breakout Meeting #2 (BO #2)
Summary of Topics
BO #1 Meeting Dates by Special District:
• American Canyon Fire Protection District –
August 14, 2024
• Howell Mountain Mutual Water Company –
September 10, 2024
• Napa County Flood Control and Water
Conservation District – October 23, 2024
• Napa County Office of Education – August 28,
2024
• Napa Valley College – August 28, 2024
• Napa Valley Transportation Authority –
September 5, 2024
• NapaSan – August 21, 2024
BO #2 Meeting Dates by Special District:
• American Canyon Fire Protection District –
June 22, 2025
• Howell Mountain Mutual Water Company –
June 3, 2025
• Napa County Flood Control and Water
Conservation District – November 4, 2025
• Napa County Office of Education – August 19,
2025
• Napa Valley College – August 19, 2025
• Napa Valley Transportation Authority – May
7, 2025
• NapaSan – June 9, 2025
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SECTION 1

JURISDICTIONAL ANNEX
City of American Canyon
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Napa County
2026 Multi-Jurisdictional Hazard Mitigation Plan Update City of American Canyon (AC)
Municipal Annex
Section 1. City of American Canyon............................................................................................ 1-9

1.1 Scope & Purpose ......................................................................................................................................................................1-9

1.2 Jurisdictional Setting............................................................................................................................................................1-9

1.2.1 Geography & Climate .................................................................................................................................................1-10

1.2.2 Demographics & Vulnerable Populations..........................................................................................................1-12

1.2.3 Economy........................................................................................................................................................................ 1-28

1.2.4 Growth Trends & Future Development.............................................................................................................. 1-28

1.3 Planning Process ................................................................................................................................................................. 1-29

1.3.1 Public Input & Draft Review ....................................................................................................................................1-31

1.4 What’s New............................................................................................................................................................................. 1-32

1.4.1 Mitigation Activities ................................................................................................................................................. 1-32

1.4.2 Mitigation Successes................................................................................................................................................ 1-33

1.5 Risk Assessment.................................................................................................................................................................. 1-36

1.5.1 Hazard Screening & Prioritization ...................................................................................................................... 1-36

1.5.2 Vulnerability to Specific Hazards........................................................................................................................1-40

1.5.3 Climate Change Impacts & Vulnerable Populations.................................................................................... 1-65

1.5.4 Hazard Problem Statements.................................................................................................................................. 1-66

1.6 Mitigation Strategy ............................................................................................................................................................. 1-70

1.6.1 Capabilities & Opportunities...................................................................................................................................1-71

1.6.2 City of American Canyon Mitigation Action Plan........................................................................................ 1-85

1.6.3 Status of Previous Mitigation Actions............................................................................................................... 1-89 CAL OES SUBMITTAL - JUNE 2026
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List of Figures
Figure 1-1: City of American Canyon Geographic Overview Map.................................................................................. 1-11 Figure 1-2: City of American Canyon Median Household Income Map ......................................................................1-15 Figure 1-3: City of American Canyon Poverty Status Map................................................................................................1-16 Figure 1-4: City of American Canyon Housing Occupancy Map....................................................................................1-17 Figure 1-5: City of American Canyon Dependent Age Groups Map ..............................................................................1-21 Figure 1-6: City of American Canyon Disabled Elderly Map ........................................................................................... 1-22 Figure 1-7: City of American Canyon Race and Ethnicity Map......................................................................................1-24 Figure 1-8: City of American Canyon Spanish-Speaking Households Map.............................................................. 1-25 Figure 1-9: City of American Canyon CDC Social Vulnerability Index Map.............................................................. 1-27 Figure 1-10: American Canyon Grazing...................................................................................................................................1-34 Figure 1-11: Wetlands Edge Project............................................................................................................................................ 1-35 Figure 1-12: City of American Canyon Risk Assessment Matrix................................................................................... 1-38 Figure 1-13: Exposure Summary – City of American Canyon Wildfire Risk.............................................................1-42 Figure 1-14: City of American Canyon Flood Risk (FEMA Zones and DWR Awareness Zone)..........................1-46 Figure 1-15: Exposure Summary – City of American Canyon Flood Risk (FEMA Zones)....................................1-47 Figure 1-15: Exposure Summary – City of American Canyon Dam Inundation Zone .......................................... 1-50 Figure 1-16: Exposure Summary – City of American Canyon Earthquake Risk (M7.1 Hunting Creek– Berryessa)............................................................................................................................................................................................ 1-53 Figure 1-17: Exposure Summary – City of American Canyon Earthquake Risk (M6.7 West Napa)................. 1-54 Figure 1-18: City of American Canyon Liquefaction Risk................................................................................................. 1-55 Figure 1-19: Exposure Summary – City of American Canyon Slope Failure Risk.................................................. 1-57 Figure 1-20: Drought Severity Timeline 2000-2026.............................................................................................................1-60 Figure 1-21: Mitigation Action Number Key........................................................................................................................... 1-85 List of Tables
Table 1-1: City of American Canyon Population and Households..................................................................................1-12 Table 1-2: City of American Canyon Income and Poverty ................................................................................................1-13 Table 1-3: City of American Canyon Renter- and Owner-Occupied Housing ...........................................................1-14 Table 1-4: City of American Canyon Households with Seniors ......................................................................................1-18 Table 1-5: City of American Canyon Households with Children....................................................................................1-19 Table 1-6: City of American Canyon Population with Disabilities and Access to Transportation ..................1-20 Table 1-7: City of American Canyon Household Languages ........................................................................................... 1-23 Table 1-8: City of American Canyon Planning Team and Steering Group Members............................................1-30 Table 1-9: City of American Canyon Planning Team Meetings......................................................................................1-31 Table 1-10: City of American Canyon Document Review of Potential Hazards ...................................................... 1-37 Table 1-11: City of American Canyon Hazards Prioritization Summary..................................................................... 1-39 Table 1-12: City of American Canyon National Flood Insurance Program Information ......................................1-44 CAL OES SUBMITTAL - JUNE 2026
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Table 1-13: Drought Classifications and Impacts................................................................................................................. 1-59 Table 1-14: Cal-Adapt Extreme Heat Thresholds.................................................................................................................. 1-62 Table 1-15: City of American Canyon Hazard Problem Statements ............................................................................. 1-67 Table 1-16: City of American Canyon Capabilities and Opportunities Assessment..............................................1-79 Table 1-17: City of American Canyon Mitigation Action Plan ........................................................................................ 1-87 Table 1-18: City of American Canyon Status of Previous Mitigation Actions ..........................................................1-89 CAL OES SUBMITTAL - JUNE 2026
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Adoption Resolution
To comply with the Federal Disaster Mitigation Act of 2000 (DMA 2000), the City of American Canyon City Council has officially adopted this 2026 Napa County Multi-Jurisdictional Hazard Mitigation Plan, including Volume 1 in its entirety as well as this Volume 2 municipal annex. The adoption of the MJHMP recognizes the city’s commitment to reducing the impacts of natural hazards within its jurisdiction and across Napa County.

A copy of the city’s adoption record is provided on the following pages. Adoption records for all jurisdictions are summarized in Volume 1, Table ES-1.

ADOPTION RECORD TO BE INSERTED UPON COMPLETION.

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Section 1.City of American Canyon

1.1 Scope & Purpose
This Jurisdictional Annex for the City of American Canyon of the 2026 Napa County Multi-Jurisdictional Hazard Mitigation Plan (MJHMP) details the hazard mitigation planning elements specific to the city’s planning area. The annex is not intended to be a standalone document but appends to and supplements the information contained in the umbrella plan document (Volume 1). As such, all sections of the umbrella plan, including the planning process and other procedural requirements, apply to and were met by the City of American Canyon. This annex provides additional information specific to the city, with a focus on hazard identification and risk assessment, vulnerability assessment, problem statements, mitigation strategy, and capabilities assessment. Below are the City of American Canyon Points of Contact:

Primary Point of Contact Alternate Point of Contact
Dominic Patrick, Water Systems Manager
City of American Canyon
4381 Broadway Street, Suite 201,
American Canyon, CA 94503
Telephone: (707) 258-1269
email: [email protected]
Alexandra Ikeda, Deputy City Manager
City of American Canyon
4381 Broadway Street, Suite 201,
American Canyon, CA 94503
Telephone: (707) 647-4360
email: [email protected]

1.2 Jurisdictional Setting
The City of American Canyon is located in southern Napa County in Northern California, approximately 35 miles northeast of San Francisco and at the northern edge of the San Pablo Bay. The city is bounded by the Napa River and associated wetlands to the west, the City of Vallejo to the south, the Napa County Airport and unincorporated Napa County lands to the north, and the eastern foothills of the Sulphur Springs Mountain Range to the east. The city is situated along Highway 29, with easy access to regional transportation networks and functions as the southern gateway to Napa County and is characterized by a mix of residential neighborhoods, commercial centers, and regionally significant industrial and wine production facilities.

American Canyon encompasses approximately 6.5 square miles and includes low-lying areas near the Napa River as well as gradually rising terrain toward the eastern hills. This varied topography and proximity to tidal waterways influence the city’s exposure to natural hazards, including flooding, seismic shaking, wildfire along the wildland–urban interface, and climate change–related impacts such as extreme heat and increased flood risk.

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wastewater, and recycled water services. Fire protection services are provided by the American Canyon Fire Protection District, an independent special district.

In addition to its incorporated boundaries, the city provides water and wastewater services to areas outside the city limits. Under California planning law, these extraterritorial service areas are considered part of the city’s planning area because damage to infrastructure beyond municipal boundaries can directly affect public health, safety, and continuity of essential services within American Canyon. The City of American Canyon’s location within Napa County and the State of California are shown in Figure 1-1. ▪ Year of Incorporation: January 1, 1992
▪ 2022 Population: 21,669 (US Census Bureau, 2022)
▪ Population Growth: Long-term population growth since incorporation, with recent increases driven primarily by residential development within established urban areas and approved specific plans.

1.2.1 Geography & Climate
The City of American Canyon is located in the southern portion of Napa County and occupies a transitional geographic setting between the Napa River and San Pablo Bay to the west and the eastern foothills of the Sulphur Springs Mountain Range to the east. The City’s western areas are characterized by low-lying floodplain and wetland environments associated with the Napa River and tidal influences from the Bay, while elevations gradually increase toward the east, transitioning into rolling hills and steeper terrain.

Figure 1-1 provides a regional location map.

Hydrologically, American Canyon is part of the Napa River watershed, which conveys runoff from northern Napa County through the City before discharging into San Pablo Bay. Portions of the City lie near or within historic floodplain areas, particularly adjacent to the Napa River and associated sloughs and wetlands.

These low-lying areas are subject to fluvial flooding, tidal backwater effects, and potential sea level rise impacts. Stormwater systems throughout the city are designed to manage runoff generated by seasonal precipitation.

American Canyon experiences a Mediterranean climate typical of Northern California, characterized by cool, wet winters and warm, dry summers. The majority of annual precipitation occurs between November and March, often in the form of moderate to heavy rain associated with atmospheric river events, averaging about 18 inches. Summers are generally dry, with extended periods of low humidity and elevated temperatures. This seasonal precipitation pattern contributes to both winter flood risk and summer drought and wildfire conditions.

Average daily temperatures are moderated by the city’s proximity to San Pablo Bay, though inland heat can develop during summer months, particularly in eastern portions of the city farther from marine influence.

Average summer temperatures range from the high 70s to mid-90s°F, while winter temperatures typically range from the mid-40s to low 60s°F. Climate change projections for the region indicate continued warming trends, increased variability in precipitation, more intense storm events, longer dry periods, and rising sea levels.

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Figure 1-1: City of American Canyon Geographic Overview Map CAL OES SUBMITTAL - JUNE 2026
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1.2.2 Demographics & Vulnerable Populations
This section describes the demographic characteristics of the City of American Canyon to guide hazard mitigation planning efforts. Natural disasters affect communities both physically and socially, with demographic composition playing a central role in determining how impacts are distributed, particularly among vulnerable groups facing greater challenges in preparedness, response, and recovery.

Understanding the area's social and economic landscape also helps assess potential social costs from infrastructure damage, including housing, industry, public facilities, essential services, and transportation.

Exploring local demographic data may help to identify groups and geographic areas with specific vulnerability to hazard events. In the context of all-hazards preparedness and response planning, at-risk individuals (often used interchangeably with “vulnerable populations”) are defined federally as “children, pregnant women, senior citizens, and other individuals who have access or functional needs in the event of a public health emergency.” (42 U.S.C. § 2802(b)(4)(B) (2019)) These populations may include, but are not limited to, individuals who are economically disadvantaged, living with disabilities, dependent on caregivers, from historically marginalized communities, have limited English proficiency or are nonEnglish speaking, lack access to transportation, are experiencing homelessness, or have chronic medical conditions.

Certain populations face greater risk following a natural hazard event due to age, economic mobility, physical disability, geographic location, or a combination of factors. Vulnerability in the face of a hazard event is not a fixed characteristic; the same individual may be at risk for some hazards but not at risk for others. Planning for vulnerable populations in the context of hazard mitigation can help communities to prioritize limited resources where they will be the most effective. Refer to Volume 1, Section 1.4.3, for a more in-depth discussion of planning for vulnerable populations, at-risk individuals with access and functional needs, and environmental justice.

The total population, total number of households, and average household size of the City of American Canyon are presented in Table 1-1, compared to the other municipalities and Napa County.

Table 1-1: City of American Canyon Population and Households Area Total Population Total Households (HH) Average HH Size Napa County 137,384 55,588 2.40
City of Napa 79,233 31,666 2.47
City of American Canyon 21,669 5,924 3.64
City of Calistoga 5,191 2,330 2.20
City of St. Helena 5,426 2,963 1.81
Town of Yountville 3,397 1,824 1.45
Source: ACS 5-Year, 2017-2022
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Income & Housing
Economic mobility is one of the most important predictors of natural hazard vulnerability. Low-income residents are more likely to occupy housing which is inadequately maintained or otherwise poorly built to withstand extreme events. For example, mobile or modular homes are more susceptible to damage in earthquakes and floods than other types of residences and are less likely to contain A/C units to cope with high heat events. In urban areas, low-income residents are more likely to occupy older homes and apartment complexes with unreinforced masonry, which is particularly susceptible to seismic damage.

Low-income households and communities face disproportionate financial burden from costs associated with disaster preparedness, response, and recovery. Disasters create unexpected expenses which may serve as “tipping points” for families and individuals living on the edge of poverty or homelessness. Recovery costs may be higher for those without resources to conduct hazard mitigation activities ahead of time. Families and individuals who lack access to transportation may be unable to evacuate ahead of an emergency. (Krause & Reeves, 2017)
Low-income residents and renters are also less likely to purchase insurance, meaning that those with the most to lose during an event are also the least prepared to deal with potential losses. Major hurricane events in recent history such as Harvey, Irma, and Katrina all demonstrate that low-income and/or historically marginalized communities face increased vulnerability to hazard events and struggle the most to recover.

Median household income in the City of American Canyon was approximately $123,000, with an overall poverty rate of around 7%. By comparison, median income and poverty rates for Napa County were nearly $106,000 and 8%, respectively. (see Table 1-2) Median income and poverty rates are also shown on the block group level in Figure 1-2 and Figure 1-3.

Table 1-2: City of American Canyon Income and Poverty
Area Median Income Poverty Rate
Napa County $105,809 7.9%
City of Napa $100,273 8.1%
City of American Canyon $122,694 7.4%
City of Calistoga $96,667 5.4%
City of St. Helena $135,781 5.7%
Town of Yountville $75,134 10.6%
Source: ACS 5-Year, 2017-2022
Renters are also more vulnerable to natural hazards, as they are less likely to take out property insurance and the decision to make major structural improvements typically lies with the property owner. Federal disaster recovery services can exacerbate inequality between renters and homeowners; payout amounts are significantly higher for homeowners applying through FEMA’s Individual Assistance (IA) program; from 1999 to 2013 U.S. homeowners saw their wealth increase with local hazard damages, whereas renters’ wealth decreased. (Howell, Junia; Elliot, James, 2019)
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Approximately 20% of occupied housing units in the City of American Canyon are renters, compared to approximately 35% for Napa County as a whole; refer to Table 1-3.

Table 1-3: City of American Canyon Renter- and Owner-Occupied Housing Jurisdiction # Occupied
Housing Units
# Renter
Occupied % Renter Occupied # Owner Occupied
% Owner
Occupied
Napa County 49,738 17,676 35.5% 32,062 64.5%
City of Napa 26,978 10,616 39.4% 16,362 60.6%
City of American Canyon 6,192 1,371 22.1% 4,821 77.9%
City of Calistoga 2,042 822 40.3% 1,220 59.7%
City of St. Helena 2,380 1,048 44% 1,332 56.0%
Town of Yountville 1,050 362 34.5% 688 65.5%
Source: ACS 5-Year, 2017-2022
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Figure 1-2: City of American Canyon Median Household Income Map CAL OES SUBMITTAL - JUNE 2026
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Figure 1-3: City of American Canyon Poverty Status Map
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Figure 1-4: City of American Canyon Housing Occupancy Map CAL OES SUBMITTAL - JUNE 2026
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Dependent & Disabled Populations
Age is a significant factor in assessing vulnerability to natural hazards. Both older adults and children are considered dependent populations due to their reliance on caregivers for safety, mobility, and support during emergency events. These populations face heightened risks during disasters such as floods, wildfires, and earthquakes, particularly when compounding factors such as poverty, disability, or social isolation are present.

In the City of American Canyon, approximately 30% of households include at least one individual over the age of 65, and over 3% of all households consist of seniors living alone. While only around 2% of senior households live below the poverty line (Table 1-4), seniors, particularly those who are low-income or socially isolated, remain among the most vulnerable populations in disaster situations. Challenges for older adults may include limited mobility, chronic health conditions, reduced digital literacy, and lack of access to realtime emergency alerts. Seniors living alone may require additional assistance during evacuations or power outages, and assisted living facilities necessitate advanced coordination to ensure continuity of care and safety during emergencies.

Children represent another dependent population requiring special consideration (Table 1-5). In American Canyon, nearly 45% of households include individuals under the age of 18, with around 7% of these households headed by a single caregiver. During emergencies, children are entirely dependent on caregivers for decision-making, transportation, and access to essential resources. Disruptions to schools, childcare, and youth services can result in significant emotional, educational, and developmental impacts.

Families with limited means or single caregivers may also face greater challenges in securing housing, supplies, and recovery assistance.

Figure 1-5 highlights areas within American Canyon with higher concentrations of economically dependent age groups, informing targeted outreach and response strategies during emergencies.

Table 1-4: City of American Canyon Households with Seniors Jurisdiction Households (HH) 65+ % 65+ Alone %
65+
Poverty %
Napa County 55,588 18,777 33.8% 4,816 8.7% 1,271 2.3%
City of American Canyon 5,924 1,772 29.9% 184 3.1% 111 1.9% City of Calistoga 2,330 1,003 43.0% 419 18.0% 101 4.3%
City of Napa 31,666 10,299 32.5% 2,674 8.4% 703 2.2%
City of St. Helena 2,963 1,153 38.9% 296 10.0% 42 1.4%
Town of Yountville 1,824 873 47.9% 351 19.2% 77 4.2%
Source: ACS 5-Year, 2017-2022
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Table 1-5: City of American Canyon Households with Children Jurisdiction Households <18 %
<18 Single
Caregiver %
Napa County 55,588 14,596 26.3% 3,109 5.6%
City of American Canyon 5,924 2,633 44.4% 417 7.0%
City of Calistoga 2,330 471 20.2% 33 1.4%
City of Napa 31,666 8,934 28.2% 2,315 7.3%
City of St. Helena 2,963 619 20.9% 168 5.7%
Town of Yountville 1,824 160 8.8% 0 0.0%
Source: ACS 5-Year, 2017-2022
Elderly populations face increased risks during disaster events due to age-related health conditions, mobility limitations, and potential social isolation. In American Canyon, approximately 10% of the noninstitutionalized population lives with a disability, a slightly higher rate than the countywide average of 12% (Table 1-6).

Among those with access and functional needs, elderly individuals with disabilities represent a highly vulnerable subpopulation when it comes to disaster preparedness, response, and recovery. This group includes seniors living with physical or cognitive impairments such as hearing or vision loss, reduced mobility, reliance on assistive medical devices, neurodivergence, or chronic health conditions that may be exacerbated by hazard events (e.g., exposure to wildfire smoke or extreme heat).

Figure 1-6 illustrates that in some portions of the city, more than 47% of the elderly population is estimated to have one or more disabilities, while other areas show lower proportions or lack available data. The spatial distribution shown on this map suggests that vulnerability is not uniform across the city and that certain neighborhoods may have greater needs for evacuation assistance, medical support, and continuity of care during emergencies. Seniors with disabilities may also be more sensitive to extended power outages, disruptions to medical services, and transportation interruptions. These risks are expected to increase under climate change conditions that intensify extreme heat events and strain emergency response resources.

The combination of advanced age and disability can present significant challenges not only during emergency response but also in implementing hazard mitigation measures. Elderly individuals with disabilities may face physical, financial, or logistical barriers to undertaking activities such as seismic retrofitting, anchoring fuel tanks, installing foundation bracing, or implementing residential flood-proofing techniques. Many live in older housing stock that is more vulnerable to earthquake damage or repetitive flooding and may lack the resources or support networks needed to complete mitigation upgrades.

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Table 1-6: City of American Canyon Population with Disabilities and Access to Transportation Jurisdiction Population
Persons
w/
Disability %
Persons
Reliant on
Public
Trans. % Households
HH w/o
Vehicle %
Napa County 137,384 16,544 12.0% 890 0.6% 55,588 2,421 4.4% City of American Canyon 21,669 2,201 10.2% 287 1.3% 5,924 138 2.3% City of Calistoga 5,191 573 11.0% 36 0.7% 2,330 83 3.6% City of Napa 79,233 9,837 12.4% 291 0.4% 31,666 1,554 4.9% City of St. Helena 5,426 683 12.6% 121 2.2% 2,963 219 7.4% Town of Yountville 3,397 683 20.1% 15 0.4% 1,824 210 11.5% Source: ACS 5-Year, 2017-2022
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Figure 1-5: City of American Canyon Dependent Age Groups Map CAL OES SUBMITTAL - JUNE 2026
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Figure 1-6: City of American Canyon Disabled Elderly Map CAL OES SUBMITTAL - JUNE 2026
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Race, Ethnicity & Language
Natural disasters compound racial disparities; non-white individuals and communities receive less recovery aid from FEMA than their white counterparts, even where the amount of damage is the same. (Howell, Junia; Elliott, James R., 2019) (National Advisory Council, 2020) These disparities are evidence of the complicated relationship between disaster recovery and overlapping social vulnerabilities including race, income, language, and health. Black and Latinx residents are more likely to be low income and renters, conditions which create barriers to navigating FEMA’s Individual Assistance programs. Communities with more non-white residents may have lower tax revenue and property values, which means less investment in mitigation and rebuilding efforts before and after an emergency.

Figure 1-7 depicts the racial and ethnic composition of the City of American Canyon. According to ACS data, the city contains a mosaic of racial and ethnic communities rather than a single dominant population citywide. Several areas are predominantly Hispanic or Latino, particularly within central and southern residential neighborhoods, while other areas are characterized by predominance of White residents or Asian residents. Smaller concentrations of other racial and ethnic groups are present throughout the city, reflecting American Canyon’s role as one of the most diverse communities in Napa County.

Residents with limited English proficiency (LEP) face heightened barriers to understanding emergency alerts, accessing preparedness resources, and navigating post-disaster recovery programs. In American Canyon, approximately 18% of households speak Spanish, but only around 2% report limited English proficiency. (Table 1-7). Figure 1-8 highlights where Spanish-speaking populations are concentrated in American Canyon.

Table 1-7: City of American Canyon Household Languages
Jurisdiction Households (HH) Spanish Speaking %
Limited
English %
Other
Lang. %
Napa County 55,588 8,738 15.7% 2,141 3.9% 12 0.0%
City of American Canyon 5,924 1,069 18.0% 177 3.0% - 0.0% City of Calistoga 2,330 474 20.3% 63 2.7% - 0.0%
City of Napa 31,666 5,800 18.3% 1,653 5.2% 9 0.0%
City of St. Helena 2,963 370 12.5% 88 3.0% - 0.0%
Town of Yountville 1,824 49 2.7% 21 1.2% - 0.0%
Source: ACS 5-Year, 2017-2022
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Figure 1-7: City of American Canyon Race and Ethnicity Map CAL OES SUBMITTAL - JUNE 2026
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Figure 1-8: City of American Canyon Spanish-Speaking Households Map CAL OES SUBMITTAL - JUNE 2026
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Social Vulnerability Index (SVI)
The Centers for Disease Control and Prevention (CDC) Social Vulnerability Index (SVI) for City of American Canyon reveals important spatial and demographic patterns that have direct implications for equitable hazard mitigation planning. As discussed in detail in Volume 1, Section 1.4.3.6, the SVI is a composite measure developed by the CDC to identify communities that are more likely to require support before, during, and after a disaster. It incorporates a range of factors across four key dimensions: socioeconomic status, household composition and disability, minority status and language, and housing type and transportation access. The resulting index score ranges from 0 (lowest vulnerability) to 1 (highest vulnerability).

Figure 1-9 shows that social vulnerability varies across American Canyon, with several census block groups exhibiting moderate to high SVI scores. Areas with higher SVI values (shown in darker blue shades) indicate neighborhoods where residents may have reduced capacity to prepare for, respond to, and recover from hazard events due to factors such as lower income, higher proportions of renters, limited access to vehicles, language barriers, or greater concentrations of elderly and disabled individuals. Conversely, areas with lower SVI scores generally reflect populations with greater access to resources and adaptive capacity.

Spatial patterns in the SVI map suggest that higher social vulnerability is concentrated in portions of the central and southern areas of the city, where multiple vulnerability indicators overlap. These areas may experience disproportionate impacts during events such as flooding, extreme heat, earthquakes, or wildfire smoke episodes, particularly if hazards coincide with power outages, transportation disruptions, or prolonged recovery periods. Residents in higher-SVI neighborhoods may also face challenges accessing emergency information, evacuation assistance, sheltering, and post-disaster financial or housing resources.

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Figure 1-9: City of American Canyon CDC Social Vulnerability Index Map CAL OES SUBMITTAL - JUNE 2026
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1.2.3 Economy
The City of American Canyon plays an important economic role within southern Napa County, serving as a regional employment center and gateway to the Napa Valley. The local economy is supported by a diverse mix of industrial, logistics, manufacturing, commercial, and service-sector activities, as well as businesses tied to the regional wine industry. American Canyon’s location along State Route 29 and its proximity to Interstate 80 provide direct access to regional transportation networks, making the city attractive for distribution, warehousing, and industrial uses.

Industrial and business park areas located primarily in the northern and western portions of the city host a concentration of employment-intensive uses, including wine production facilities, food and beverage manufacturing, logistics operations, and light industrial businesses. These employment centers contribute significantly to local tax revenues and provide jobs for residents of American Canyon and surrounding communities. At the same time, the concentration of economic activity in these areas increases the importance of protecting critical infrastructure, transportation corridors, and utility systems from natural hazards such as flooding, earthquakes, and power outages.

The city’s commercial economy includes neighborhood-serving retail, restaurants, and personal services that support daily needs and contribute to community vitality. These businesses are particularly sensitive to hazard-related disruptions, as temporary closures, infrastructure damage, or reduced access can result in lost income and longer-term economic impacts. Small businesses may have limited capacity to absorb prolonged disruptions, making economic resilience an important consideration in hazard mitigation planning.

A significant portion of American Canyon’s workforce is employed in sectors that involve physical labor or outdoor activity, including industrial operations, logistics, construction, and public services. These workers may face heightened exposure to hazards such as extreme heat, wildfire smoke, and poor air quality.

Climate change projections indicating more frequent heat events and longer wildfire seasons have implications for worker safety, productivity, and business continuity within these sectors.

Economic vulnerability is also influenced by income variability and employment stability. Workers in hourly or service-based positions may experience immediate income loss during disaster-related closures or evacuations, which can compound household vulnerability and slow community recovery. Protecting employment centers, maintaining transportation access, and ensuring continuity of utilities and communications are therefore key components of reducing economic disruption from hazard events.

1.2.4 Growth Trends & Future Development
The City of American Canyon has experienced steady growth since its incorporation, with development patterns shaped by adopted growth management policies, infrastructure capacity, and regional housing demand. Growth in recent decades has occurred primarily through planned residential development, mixed-use projects, and expansion of industrial and business park areas within the city’s established urban footprint. This approach reflects the city’s long-standing emphasis on directing growth toward areas that CAL OES SUBMITTAL - JUNE 2026
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can be efficiently served by public services and infrastructure while limiting outward expansion into agricultural and environmentally sensitive lands.

Residential growth has been driven largely by approved specific plans and infill development within existing neighborhoods. Recent development activity has included a mix of single-family and multi-family housing intended to accommodate population growth and meet state-mandated housing requirements. The city’s Housing Element and Annual Progress Reports document continued efforts to increase housing supply while addressing affordability, infrastructure demands, and community character.

Future development in American Canyon is expected to continue focusing on buildout of remaining developable parcels within the Urban Limit Line and Sphere of Influence. Planned growth areas are generally located near existing transportation corridors, utilities, and employment centers, supporting more compact and efficient development patterns. This strategy reduces the need for extensive new infrastructure and helps limit exposure to hazards associated with hillside development, wildfire risk, and access constraints.

Economic development is also anticipated to remain a key component of future growth. Expansion and intensification of industrial and commercial uses, particularly those related to logistics, manufacturing, and the wine industry, are expected to support employment and fiscal stability. At the same time, continued development in low-lying areas and near critical transportation routes underscores the importance of incorporating hazard mitigation and climate adaptation measures into future land use and infrastructure planning.

1.3 Planning Process
The City of American Canyon followed the planning process detailed in Volume 1, Section 2, including participating in the county-wide Hazard Mitigation Planning Team (HMPT) and formulating their own internal planning team to support the broader planning process.

The city’s representatives in the Steering Group led stakeholder and public engagement efforts alongside the Consultant Team, with assistance from the county-wide HMPT and their internal planning team. This engagement process is described in Volume 1. Specifically, for the City of American Canyon, this included postings to the city website and social media, and outreach events, as documented in Appendix B. Examples of Key Stakeholders engaged by Napa County on behalf of the city with relevance to the development of American Canyon’s mitigation strategy include the USDA and other federal agencies; CAL FIRE and other state agencies; other jurisdictions; community-based organizations such as local Chamber of Commerce chapters; utility providers like PG&E; UC Davis and other academia; and local businesses.

All Key Stakeholders that were invited to participate in the planning process are listed in Volume 1, Section 2, and the input received from stakeholders was integrated into the city’s annex, as described in Volume 1 Table 2-9. The city’s internal planning team participants, their positions, and how they participated in the planning process are shown in Table 1-8.

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Table 1-8: City of American Canyon Planning Team and Steering Group Members Team Members Title Description of Involvement
Dominic Patrick Water Systems Manager Lead Point-of-Contact, HMPT #1, and #2, BO #1 Alexandra Ikeda Deputy City Manager Alternate Point-of-Contact, HMPT #4 Erica Ahmann Smithies Public Works Director Participating Stakeholder, BO #1 and #2 Jason Holley City Manager Participating Stakeholder, BO #1 City of American Canyon participated in a comprehensive hazard mitigation planning process as part of the 2026 Napa County MJHMP update. This included a series of breakout meetings, listed in Table 1-9 that engaged the district’s planning team, which included key city personnel and stakeholders in evaluating hazards, identifying local vulnerabilities, and prioritizing mitigation strategies The process began with a County-Wide Steering Group Kickoff Meeting on February 28, 2024. This initial meeting focused on welcoming participants, establishing a shared understanding of the project scope and schedule, clarifying roles and responsibilities of the Steering Group, the county-wide Hazard Mitigation Planning Team (HMPT), and individual jurisdictional planning teams, and included a review of key changes since the 2020 Local Hazard Mitigation Plan The meeting set the foundation for coordinated participation throughout the planning effort.

On December 10, 2025, participants engaged in a hexagon mapping activity designed to visually identify mitigation actions that could benefit from or require inter-jurisdictional coordination. These collaborative efforts helped shape a refined set of mitigation alternatives, establish shared planning goals, and align local strategies with FEMA’s Hazard Mitigation Assistance (HMA) funding framework.

Throughout the series of breakout meetings, the City of American Canyon engaged in a structured and collaborative planning process focused on assessing hazard risks, identifying vulnerabilities, and developing targeted mitigation strategies. The meetings began with recaps of the county-wide HMPT meetings to ensure alignment of goals and progress.

During the October 1, 2024, breakout out meeting, discussions concentrated on community engagement outcomes, initial risk assessments, and the integration of demographic data to better understand vulnerable populations. Jurisdictional teams reviewed their specific hazard exposures using the Risk Assessment Mapping Platform (RAMP) and participated in prioritization exercises to identify their top hazards.

The January 29, 2026, breakout meeting shifted toward reviewing local capabilities and defining specific areas of concern, which informed the drafting of problem statements. Teams worked collaboratively to refine mitigation alternatives, align actions with FEMA guidelines, and develop a shortlist of priority mitigation actions and inter-jurisdictional collaboration opportunities.

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The meetings also included consensus-building activities around hazard rankings, capabilities, and planned actions, while providing regular updates on the overall project schedule.

Table 1-9: City of American Canyon Planning Team Meetings Meeting & Date Agenda / Topics Goals / Key Inputs
County-Wide Steering Group and HMPT Kick-off and Meetings #1 & #2 February 28, 2024– July 18, 2024
American Canyon
Planning Team
Breakout Meeting #1
October 1, 2024
▪ County-wide HMPT meetings #1 and #2 recaps
▪ Community engagement progress and results
▪ Risk assessment and community vulnerability
▪ Demographics and vulnerable populations
▪ Overview of jurisdiction-specific hazard risks and
exposure
▪ Introduction to Risk Assessment Mapping Platform
(RAMP)
▪ Jurisdiction-specific hazard risk ranking exercise
▪ Project schedule updates and next steps
▪ Consensus on jurisdictionspecific priority hazards
▪ Identify capabilities and
potential mitigation actions
▪ Community engagement
volunteers
County-Wide HMPT Meeting #3
March 25, 2025
American Canyon
Planning Team
Breakout Meeting #2
January 29, 2026
▪ Breakout Meeting #1 and HMPT #3 recaps
▪ Review capabilities assessment
▪ Review areas of concern and define problem
statements
▪ Principles of effective mitigation strategies and
actions, and mitigation alternatives
▪ Refine and align jurisdiction-specific mitigation
actions exercise
▪ Project schedule updates and next steps
▪ Consensus on jurisdictionspecific capabilities
▪ Consensus on jurisdictionspecific areas of concern
▪ Consensus on priority
mitigation actions and
collaboration opportunities
▪ Community engagement
volunteers
County-Wide HMPT Meeting #4
December 10, 2025

1.3.1 Public Input & Draft Review
As detailed in Volume 1, Section 2, the draft plan was available for public review and comment from May 15 to June 2, 2026. Public comments received during that time were similar to those gathered throughout the public engagement process, including the need for more equity in the distribution of mitigation activities and funding and the need for enhanced cooperation among jurisdictions, utility providers, and state agencies. These comments were incorporated into the city’s mitigation strategy, as appropriate; although, most were already addressed by the Mitigation Action Plan which was based on previous public input.

Public and stakeholder input was gathered and incorporated throughout the plan development process, before the public review period, such as from the online public survey (see Volume 1, Section 2.1.2 and CAL OES SUBMITTAL - JUNE 2026
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Appendix B, for details). During the review period, jurisdictional staff and stakeholders that participated in the plan development also reviewed the public draft and provided comments on minor corrections and revisions, which were addressed in the final plan.

1.4 What’s New
This section provides an overview of hazard mitigation planning efforts for the planning area and highlights the updates made in the 2026 MJHMP. The City of American Canyon previously participated and maintained a Hazard Mitigation Plan, which guided resilience planning and hazard mitigation actions at the city level. American Canyon is updating their current plan on a county wide level. This integration reflects the city’s ongoing commitment to regional resilience and acknowledges that many hazards such as coastal flooding, severe storms, and earthquakes cross jurisdictional boundaries.

Through participation in the MJHMP, American Canyon has identified its highest priority hazards, developed hazard specific problem statements, and proposed actionable strategies to reduce risks. By aligning with countywide partners and leveraging regional resources, American Canyon has strengthened its capacity to prepare for, withstand, and recover from disasters while continuing to protect its unique coastal community character.

1.4.1 Mitigation Activities
The city has successfully implemented several initiatives aimed at addressing identified vulnerabilities.

Some of these accomplishments are highlighted in this section and have directly contributed to reducing risks from hazards such as flooding, all hazards, and severe weather. These completed projects showcase American Canyon’s ability to effectively plan, fund, and execute measures that protect its residents and infrastructure.

In addition, American Canyon has systematically reviewed and adjusted its mitigation actions, exemplifying adherence to FEMA’s Planning Policy Guide principles and emphasizing the importance of dynamic and adaptive mitigation planning. By fostering partnerships, leveraging funding opportunities, and prioritizing equity in implementation, the city aligns with best practices to build resilience against natural disasters. This ongoing effort is a testament to the city's commitment to the principles of risk-informed decision-making, equitable resource allocation, and integration with broader regional and state hazard mitigation objectives.

Adjustments to Previous Mitigation Actions
A significant portion of the city's mitigation efforts remain ongoing or in the pipeline. These actions, ranging from infrastructure upgrades to community outreach initiatives, represent the city’s proactive approach to addressing hazards as resources become available.

Recognizing constraints such as limited funding, staffing, and shifting priorities, the city has reevaluated certain initiatives, leading to their reprioritization or canceling of mitigation actions. Factors such as feasibility, cost-effectiveness, and emerging risks informed these decisions, ensuring alignment with the CAL OES SUBMITTAL - JUNE 2026
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city’s updated hazard mitigation goals. Adjustments to previous mitigation actions are documented as part of the City of American Canyon’s Mitigation Action Plan Table 1-17, and more specific status updates are provided in Table 1-18.

1.4.2 Mitigation Successes
Since the adoption of the 2021 Hazard Mitigation Plan, the City of American Canyon has made measurable progress in implementing mitigation actions that reduce risk and enhance community resilience. These successes reflect the City’s continued commitment to integrating hazard mitigation into local planning, capital improvement projects, and community programs.

The following success stories highlight completed and ongoing efforts that address key hazards such as wildfire, flooding, and infrastructure vulnerability. Collectively, these initiatives demonstrate the city’s ability to move from planning to implementation by leveraging partnerships, securing funding, and advancing projects that provide long-term risk reduction benefits to the community.

Vegetation Management
In September 2023, the City of American Canyon, in partnership with Napa County Fire, the American Canyon Fire Protection District, and the Napa Communities Firewise Foundation, implemented a sheep grazing program as a natural vegetation management strategy (Figure 1-10). The program utilizes sheep from a local producer to reduce dry grasses and other flammable vegetation in targeted areas, supporting wildfire risk reduction while aligning with the city’s sustainability and environmental stewardship goals.

Sheep grazing provides an effective alternative to conventional vegetation management methods that rely on chemical herbicides or heavy machinery. The approach improves soil health through natural fertilization, enhances biodiversity, and allows for quiet, non-disruptive treatment of areas that may be difficult to access with equipment. By reducing fuel loads, the program helps create a more fire-resistant landscape and improves visibility in parks, vacant lots, and public spaces, contributing to both wildfire mitigation and community safety.

The grazing program also represents a cost-effective and environmentally responsible mitigation measure.

By lowering long-term vegetation management costs, the city is able to allocate resources more efficiently while advancing public safety, climate resilience, and ecological health. This initiative demonstrates American Canyon’s commitment to innovative, sustainable hazard mitigation practices that reduce wildfire risk and support overall community resilience.

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Wetlands Restoration and Public Access Project
In June 2025, the San Francisco Bay Restoration Authority (SFBRA) awarded the City of American Canyon a $1,200,000 Measure AA grant to advance Phase II of the American Canyon Wetlands Restoration and Public Access Project. This funding supports planning-phase activities that will lay the groundwork for future habitat restoration, flood risk reduction, and public access improvements along the lower Napa River shoreline.

Figure 1-10: American Canyon Grazing
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Phase II will build on earlier studies and outreach by completing detailed technical investigations, 60 percent design documents, California Environmental Quality Act (CEQA) documentation, and draft regulatory permit applications. The project area includes more than 60 acres of wetlands and adjacent transitional upland habitat along the North Slough and Lower Napa River, an ecologically significant landscape that supports migratory birds, fish species, and other wildlife.

A key element of the Phase II work is to improve the resilience of the San Francisco Bay Trail by raising approximately 1.2 miles of existing trail out of the floodplain, increasing its ability to withstand future sea level rise and reduce seasonal flooding impacts. The project also aims to improve fish passage, enhance water quality, and expand public safety and recreation opportunities, including development of a new Bay Water Trail trailhead and associated facilities.

Figure 1-11: Wetlands Edge Project
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Stormwater Program Implementation
Stormwater program implementation (ongoing) to reduce flooding/erosion and protect water quality. The City’s stormwater program description emphasizes reducing flooding and erosion and participating in the Napa Countywide Stormwater Pollution Prevention Program for consistent stormwater regulation across Napa County municipalities.

Updated Safety Element
The Safety Element update includes multiple mitigation-forward policies such as tailored evacuation messaging for single-access neighborhoods, assessing ingress/egress improvements, zone-based evacuation planning, siting critical infrastructure outside hazard zones where feasible, and maintaining participation in the Napa County MJHMP update cycle.

1.5 Risk Assessment
This section focuses on profiling hazards specific to the City of American Canyon and assessing vulnerability independent of the broader county-wide planning area, which has been evaluated in Section 3 of Volume 1. The hazard profiles in Volume 1 discuss overall impacts to the planning area and describe relevant plans, policies, and regulations; past events; location; frequency and probability of future occurrences; severity and extent; warning time; secondary hazards; and climate change impacts. For more information on risk assessment methodologies, see Volume 1, Appendix A.

This section includes a tailored vulnerability assessment, analyzing assets at risk such as population, property, and critical facilities and infrastructure unique to the city, and information on city-specific differences in hazard vulnerability across the planning area. It also identifies total city assets at risk, including people, property, and critical facilities and infrastructure within the city. In addition, this section presents growth and development trends for the community, offering insights into vulnerabilities and risks that represent the broader context of assets at risk.

1.5.1 Hazard Screening & Prioritization
Members of the Planning Team from each participating jurisdiction came together to collaboratively decide which county-wide hazards would be included in the MJHMP, and which would be excluded. Hazard screening and prioritization took place early in the process and integrated historic data, local knowledge, and consensus opinions to create a risk assessment matrix for the county as well as for each participating jurisdiction. These matrices indicate the priority of hazards prior to further refinement. Details about this process, the results of the discussion, and in-depth profiles for county-wide hazards can be found in Volume 1, Sections 2 and 3.

The City of American Canyon’s internal planning group used the same hazard identification and prioritization process as the county-wide Planning Team. They reviewed previously prepared hazard mitigation plans and other relevant documents to determine the realm of natural hazards that have the potential to affect the city. Table 1-10 provides a crosswalk of hazards identified in select planning CAL OES SUBMITTAL - JUNE 2026
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documents, including the 2020 Napa County MJHMP, 2025 City of American Canyon General Plan, and the 2023 State of California HMP. The crosswalk was used to develop a preliminary hazards list, providing a framework for the group to evaluate which hazards were truly relevant to the City of American Canyon and which ones were not.

The internal planning group then ranked hazards based on their probability of affecting City of American Canyon and potential impacts on the community. Figure 1-12 displays the results of the hazard risk ranking exercise that was performed before further refinement. All hazards have been profiled in Volume 1 of this document. The purpose of this annex is to specifically address the city’s vulnerability to specifically identified hazards.

Table 1-10: City of American Canyon Document Review of Potential Hazards Hazard 2020 Napa County
MJHMP
2025 City of American
Canyon General Plan
2023 California
SHMP
Agricultural Pests ■ ■
Avalanche ■
Climate Change ■ ■ ■
Coastal ■
Dam Failure ■ ■
Drought ■ ■ ■
Earthquake / Liquefaction ■ ■ ■
Extreme Cold ■
Extreme Heat ■ ■
Extreme Weather / Storms ■ ■ ■
Flood ■ ■ ■
Geologic / Mass Movement ■ ■ ■
Human-Caused ■
Insects ■
Levee Failure ■
Pandemic Disease ■ ■
Sea Level Rise ■
Soil ■
Subsidence ■
Tornado ■
Tsunami / Seiche Wave ■
Volcano ■
Wildfire ■ ■ ■
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Figure 1-12: City of American Canyon Risk Assessment Matrix Note: Hazard naming in the Risk Assessment Matrix may not match the final naming used. Refer to hazards prioritization summary table.

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Priority Hazards
The results of the initial risk ranking exercise completed by the city’s Planning Team, before further refinement, are identified in the county’s completed matrix in Figure 1-12. Table 1-11 provides the final list of priority hazards and subhazards with additional details about why certain hazards were chosen and why others were not prioritized. However, it should be noted that many hazards not prioritized for profiling are briefly discussed as secondary or compounding hazards, and subhazards that were profiled and included in the risk assessment are listed specifically.

Table 1-11: City of American Canyon Hazards Prioritization Summary Hazard Priority Explanation
Earthquake / Liquefaction High Profiled in Volume 1, Section 3.3.4, and Section 1.5.2.4 in this annex, including Liquefaction
Wildfire High Profiled in Volume 1, Section 3.3.1, and Section 1.5.2.1 in this annex Flood Medium Profiled in Volume 1, Section 3.3.2, and Section 1.5.2.2 in this annex, including Levee Failure
Levee Failure Medium Profiled in Volume 1, Section 3.3.2, and Section 1.5.2.2 in this annex under Flood
Extreme Weather / Storms High
Profiled in Volume 1, Section 3.3.5, and Section 1.5.2.7 in this annex as Severe Weather, including High Wind and Heavy Rain (Winter Weather not a priority due to low probability and impact potential) Drought High Profiled in Volume 1, Section 3.3.6, and Section 1.5.2.6 in this annex Geologic / Mass Movement Medium Profiled in Volume 1, Section 3.3.5, and Section 1.5.2.5 in this annex as Slope Failure
Extreme Heat High Profiled in Volume 1, Section 3.3.8, and Section 1.5.2.8 in this annex Agricultural Pests -
Profiled in Volume 1, Section 3.3.9; not a priority due to low probability and impact potential
Sea Level Rise High Profiled in Volume 1, Section 3.3.9, and Section 1.5.2.9 in this annex under Climate Change
Climate Change High
Profiled in Volume 1, Section 3.3.9, and Section 1.5.2.9 in this annex, including Sea Level Rise, and discussed as a compounding hazard in relevant profiles
Dam Failure Medium Profiled in Volume 1, Section 3.3.3, and Section 1.5.2.3 in this annex CAL OES SUBMITTAL - JUNE 2026
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1.5.2 Vulnerability to Specific Hazards
Assessing vulnerabilities exposes the unique characteristics of individual hazards and begins the process of narrowing down which areas within the city are vulnerable to specific hazard events. The vulnerability assessment considered unique local knowledge of hazards and impacts and a GIS overlaying method for examining such vulnerabilities in more depth. Using these methods, the city’s planning group estimated vulnerable populations, properties, and assets, and potential losses. In addition, the exposure of city assets to drought, geological, earthquake, wildfire and flood hazards were also considered.

Many of the hazard profiles include a snapshot map and damage estimation tables that illustrate the city’s vulnerabilities to those specific hazards. These maps assisted the planning group in understanding the hazard exposure of populations, parcels, and critical facilities and infrastructure. Each snapshot map contains an exposure summary that displays the percentage of the population, the improvement and content value of parcels, and the amount of critical infrastructure that is exposed. For hazards without geospatial extents, such as drought and severe weather, narratives are provided instead of exposure maps and tables.

Based on the hazard prioritization exercise, this vulnerability assessment focuses on seven hazards for the City of American Canyon, some of which encompass sub hazards such as Liquefaction and Heavy Rain Wildfire
SECTION 1.5.2.1
Flood
SECTION1.5.2.2
Dam Failure
SECTION 1.5.2.3
Earthquake
SECTION 1.5.2.4
Slope Failure
SECTION 1.5.2.5
Drought
SECTION 1.5.2.6
Severe Weather
SECTION 1.5.2.7
Extreme Heat
SECTION 1.5.2.8
Climate Change
SECTION 1.5.2.9
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Wildfire Hazard
Wildfire risk in the City of American Canyon is primarily concentrated along the eastern and western edges of the community, where developed areas interface with open space, wetlands, and the foothills of the Sulphur Springs Mountain Range. The wildfire risk exposure map, Figure 1-13, shows that portions of the city and surrounding Sphere of Influence are located within Moderate and High Fire Hazard Severity Zones, particularly in areas adjacent to undeveloped land and wildland vegetation.

The eastern boundary of American Canyon, which transitions into rolling hills and open space east of State Route 29 and near American Canyon Road, is characterized by Moderate wildfire hazard. These areas contain grasslands, shrubs, and seasonal vegetation that can dry rapidly during summer and fall months, increasing the potential for fast-moving fires under windy or extreme heat conditions. Residential neighborhoods located near this wildland–urban interface (WUI) may face heightened risk related to ember intrusion, evacuation constraints, and access limitations during wildfire events.

Moderate-high wildfire hazard areas are also present along portions of the City’s western edge near the Napa River and adjacent wetlands. While these areas are influenced by tidal waters and marsh conditions that generally reduce ignition potential, seasonal drying of vegetation and wind conditions can still contribute to localized wildfire risk, particularly during extended drought periods.

The exposure summary associated with the wildfire risk map indicates that, within current mapped hazard areas, there are no permanent residential populations, parcels, or critical infrastructure classified within the Very High Fire Hazard Severity Zone inside city limits. As a result, population exposure, parcel exposure, and critical infrastructure exposure rates within the highest hazard category are reported as zero percent.

This reflects American Canyon’s relatively urbanized development pattern and limited extent of very highrisk wildfire terrain within incorporated boundaries.

Despite the absence of Very High Fire Hazard Severity Zones within the city, wildfire remains an important planning consideration due to proximity to higher-risk areas outside city limits, regional wildfire activity, and secondary impacts such as smoke exposure, power shutoffs, transportation disruptions, and evacuation demands. Climate change projections indicating hotter temperatures, longer dry seasons, and increased frequency of extreme weather events are expected to exacerbate wildfire conditions throughout Napa County, including areas surrounding American Canyon.

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Figure 1-13: Exposure Summary – City of American Canyon Wildfire Risk CAL OES SUBMITTAL - JUNE 2026
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Flood Hazard
Flooding is a significant natural hazard for the City of American Canyon due to its low-lying topography, proximity to the Napa River, and location adjacent to San Pablo Bay. Portions of the City are subject to riverine flooding, tidal flooding, and storm-driven inundations, particularly during major precipitation events, high tides, or conditions influenced by sea level rise. Flood hazard areas within American Canyon are primarily concentrated along the western edge of the city near the Napa River and bayfront, as well as along localized drainage corridors.

The FEMA Flood Risk Exposure map, Figure 1-15, shows areas within the 100-year (1-percent annual chance) and 500-year (0.2-percent annual chance) floodplains, including mapped floodway areas and zones protected by levees. These flood-prone areas reflect the combined influence of river overflow, tidal backwater effects, and constrained drainage capacity. Flood hazards in these areas may be exacerbated during extreme storm events when high river flows coincide with elevated bay water levels.

Exposure analysis indicates that approximately 1,620 residents, representing around 7 percent of the city’s population, are located within mapped flood hazard areas. In addition, over 200 parcels (about 3 percent of all parcels) are exposed to flooding, with an estimated $128 million in building improvement value and a similar amount in contents value at risk. While no essential facilities or hazardous materials sites are located within the mapped flood hazard areas, several transportation and lifeline facilities intersect floodprone zones, highlighting the potential for access disruptions and service interruptions during flood events.

Flooding in American Canyon can result in structural damage to buildings, roadway inundation, utility system impacts, and long-term economic disruption. Repetitive or prolonged flooding may also affect industrial and commercial areas near the river, compounding recovery challenges. Secondary impacts include erosion, sediment deposition, and degradation of wetlands and shoreline infrastructure.

Climate change is expected to increase flood risk in American Canyon over time. Projections for sea level rise, more intense precipitation events, and higher storm surge heights may expand flood extents, increase flood depths, and reduce the effectiveness of existing levees and drainage systems. Areas currently mapped within the 500-year floodplain may experience more frequent flooding in the future, increasing exposure to residents, infrastructure, and economic assets.

National Flood Insurance Program
The National Flood Insurance Program (NFIP) makes federally backed flood insurance available to homeowners, renters, and business owners in participating communities. FEMA has prepared a detailed Flood Insurance Study (FIS) for Napa County and municipalities. The study presents water surface elevations for floods of various magnitudes, including the 1% annual chance flood (100-YR flood) and the

0.2% annual chance flood (500-YR flood). Base flood elevations and the boundaries of the 100- and 500-YR floodplains are shown on Flood Insurance Rate Maps (FIRMs), which are the principal tools for identifying the extent and location of the flood hazard. FIRMs are the most detailed and consistent data source CAL OES SUBMITTAL - JUNE 2026
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available, and for many communities they represent the minimum area of oversight under their floodplain management program. See Section 4 of Volume 1 for general information on the NFIP.

The City of American Canyon has participated in the NFIP since 1994 and has adopted the most recent FIRMs and FIS issued by FEMA (dated August 3, 2016) as well as local floodplain development regulations in compliance with the minimum NFIP standards (American Canyon Municipal Code Chapter 8.16). These minimum standards include procedures and provisions for substantial improvements and substantial damages to existing structures, the latter of which are employed by the floodplain administrator and city building inspectors following any hazard event affecting structures located in the flood hazard area in accordance with NFIP requirements. Regulations for substantial improvements are enforced via permitting procedures. Implementation and enforcement of the city’s floodplain regulations are assigned to the City Manager, who serves as the floodplain administrator.

The City of American Canyon is currently in good standing with the provisions of the NFIP. Compliance is monitored by FEMA regional staff and by the California Department of Water Resources under a contract with FEMA. Maintaining compliance under the NFIP is an important component of flood risk reduction. See Table 1-12 for more information on the City’s policies and historic flood insurance claims.

Table 1-12: City of American Canyon National Flood Insurance Program Information City of American Canyon NFIP Status and Flood Insurance Statistics NFIP Status Participating Since 1/11/94
Community Identification (CID) 060755
CRS Class (Entry Date) N/A
Policies in Force (Total Coverage) 16 ($4,173,000)
Policies Inside SFHA / Outside SFHA 4 Inside / 12 Outside Policies in Coastal Zones (Total Coverage) N/A
Total Claims (Total Paid) 0 Claims ($0 Paid)
Repetitive Loss (RL) / Severe Repetitive Loss (SRL) Properties No RL or SRL Properties Repetitive Loss Payments No RL Payments
Note: The number of policies is by property and does not count policies for individual buildings. The Privacy Act of 1974 (5 USC 522a) restricts the release of certain types of data to the public. Flood insurance policy and claims data is included in the list of restricted information. FEMA can only release such data to state and local governments, and only if the data is used for floodplain management, mitigation, or research purposes. Therefore, this plan does not identify the repetitive loss properties or include claims data for any individual property.

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Principal Flooding Sources
The principal flooding source for the City of American Canyon is the Napa River, with secondary influence from tidal flooding associated with San Pablo Bay.

Riverine flooding from the Napa River is the primary driver of mapped flood risk in American Canyon.

During major storm events, high river flows can overtop banks or exceed channel capacity, particularly along the City’s western edge where development, wetlands, and infrastructure are adjacent to the river.

Tidal backwater effects from San Pablo Bay significantly influence flooding conditions in American Canyon.

High tides can slow or prevent stormwater and river flows from draining efficiently into the bay, increasing flood depths and duration along the lower Napa River and adjacent low-lying areas. These effects are especially pronounced when high tides coincide with heavy rainfall.

Localized flooding from creeks, drainage channels, and stormwater systems occurs within the city but generally represents a secondary source compared to the combined riverine and tidal flooding associated with the Napa River system.

Levee Failure
Leveed floodplains and bayfront areas further define flood risk. Portions of American Canyon lie behind levees or within areas influenced by both the 100-year and 500-year floodplains. While levees provide protection under certain conditions, they can be overtopped or lose effectiveness during extreme events or with future sea level rise.

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Figure 1-14: City of American Canyon Flood Risk (FEMA Zones and DWR Awareness Zone) CAL OES SUBMITTAL - JUNE 2026
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Figure 1-15: Exposure Summary – City of American Canyon Flood Risk (FEMA Zones) CAL OES SUBMITTAL - JUNE 2026
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Dam Failure Hazard
Dam failure represents a low-frequency but potentially high-consequence hazard within the City of American Canyon. Dam failure refers to the partial or complete structural failure of an upstream dam, resulting in the uncontrolled release of stored water. Figure 1-16 indicates that limited portions of the service boundary fall within mapped dam inundation zones. Exposure metrics identify approximately 89 residents, representing roughly 6 percent of the mapped population, and 65 parcels, or approximately 5 percent of parcels, as located within potential inundation areas. While the overall exposure footprint is comparatively small relative to other hazards, dam failure scenarios warrant consideration due to their rapid onset characteristics and potential severity.

Dam failure hazards are typically associated with structural failure, overtopping, seismic impacts, internal erosion, extreme precipitation events, or operational malfunctions affecting reservoir containment systems. In mountainous environments such as Howell Mountain, failure scenarios may produce sudden downstream flooding, high-velocity flow conditions, debris transport, and localized erosion. The steep terrain and confined drainage corridors characteristic of the region can amplify flow velocities and reduce warning times, increasing the potential for infrastructure damage and life safety risks.

Potential dam failure impacts within the City of American Canyon primarily relate to downstream flooding and associated secondary effects. Sudden inundation may damage residential structures, roadways, utility infrastructure, and distribution system components located within flood pathways. Floodwaters may also transport sediment, debris, and contaminants that affect water quality and treatment operations. Access routes critical for emergency response and infrastructure repair may be disrupted or rendered impassable.

Seismic hazards represent a particularly relevant consideration for dam failure risk. Earthquake events may induce structural stresses, foundation instability, or embankment damage affecting reservoir systems.

Given the region’s known seismic exposure, dam safety considerations are closely linked to broader geologic hazard planning. Extreme weather events, including intense rainfall or prolonged storm activity, may also influence reservoir performance through increased inflows, slope saturation, and erosion processes.

Although the mapped exposure rates for dam inundation are relatively low, the economic implications may be significant at the parcel level. Structures located within inundation zones may face elevated risk of damage, financial loss, and prolonged recovery timelines following a failure event. The Dam Inundation Exposure snapshot indicates tens of millions of dollars in parcel value within the hazard area, illustrating the potential economic consequences of a low-probability but high-impact scenario.

Dam safety oversight, inspection, and emergency action planning are managed at the state and regional levels, including by the California Department of Water Resources and the California Division of Safety of Dams. These agencies work with dam owners and local jurisdictions to monitor dam conditions and coordinate emergency notification procedures.

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For the City of American Canyon, dam failure hazards also intersect with operational considerations.

Reservoir integrity is fundamental to raw water storage, treatment reliability, and distribution continuity.

Structural compromise of storage facilities may reduce system capacity, disrupt service delivery, and necessitate emergency repairs. Secondary effects such as sedimentation, contamination, or infrastructure access constraints may further affect system performance.

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Figure 1-16: Exposure Summary – City of American Canyon Dam Inundation Zone CAL OES SUBMITTAL - JUNE 2026
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Earthquake Hazard
The City of American Canyon is subject to significant earthquake risk due to its location within the seismically active San Francisco Bay Area and proximity to multiple active faults in Napa County and the surrounding region. Earthquake impacts in the city are best illustrated through scenario modeling, including the Hunting Creek–Berryessa Earthquake Scenario (Magnitude 7.1) and the West Napa Earthquake Scenario (Magnitude 6.7). These scenarios reflect credible seismic events that could produce strong to severe ground shaking throughout the city.

Under the Hunting Creek–Berryessa M7.1 scenario (Figure 1-17), ground shaking across American Canyon is generally characterized as Moderate to Strong (Modified Mercalli Intensity [MMI] VI–VII). While exposure summaries indicate no population, parcels, or critical infrastructure located in the highest modeled intensity categories for this scenario within city limits, the widespread nature of strong shaking suggests possible but limited damage to buildings, infrastructure, and lifelines, particularly older structures and nonductile construction.

The West Napa Earthquake M6.7 scenario, Figure 1-18, represents a more impactful event for American Canyon due to its closer proximity. Under this scenario, 100 percent of the City’s population, parcels, and assessed parcel value are exposed to Strong to Very Strong shaking (MMI VII–VIII). Exposure summaries indicate that approximately 22,000 residents, 7,000 parcels, and nearly $7.0 billion in building improvement value and $7.6 billion in content value fall within these intensity ranges. In addition, all mapped critical infrastructure categories, including essential facilities, hazardous materials sites, high potential loss facilities, and transportation and lifeline systems, are exposed to damaging levels of ground shaking.

Earthquake impacts associated with these scenarios include structural damage to residential, commercial, and industrial buildings; failure of non-structural components; disruption of transportation corridors such as State Route 29 and American Canyon Road; and damage to utilities including water, wastewater, power, and communications systems.

Secondary earthquake hazards also present a concern for American Canyon. These include hazardous materials releases from industrial and commercial facilities, fires following earthquakes, prolonged power outages, and limited access for emergency response due to damaged roadways or bridges. Given the city’s role as an employment center and transportation gateway in southern Napa County, such disruptions could have regional economic and public safety consequences.

Liquefaction
Liquefaction represents a significant secondary earthquake hazard for the City of American Canyon due to local soil conditions, groundwater characteristics, and proximity to the Napa River and San Pablo Bay.

Liquefaction occurs when saturated, loose, fine-grained soils temporarily lose strength during intense ground shaking, causing the ground to behave more like a liquid. This phenomenon can result in ground settlement, lateral spreading, loss of bearing capacity, and damage to buildings, roadways, and buried CAL OES SUBMITTAL - JUNE 2026
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utilities. While liquefaction is a consideration in hazard mitigation planning, it is not profiled as a standalone hazard but addressed as a secondary earthquake effect.

Areas of American Canyon with higher liquefaction susceptibility are generally located in low-lying portions of the city underlain by young alluvial, estuarine, and bay-margin sediments. These conditions are most prevalent near the Napa River, wetlands, and former tidal areas, where shallow groundwater levels increase the likelihood of liquefaction during moderate to strong earthquake shaking (FIGURE). In these areas, even structures designed to withstand seismic forces may experience damage if foundations or supporting soils lose stability.

Liquefaction can significantly amplify earthquake impacts by damaging lifeline infrastructure such as water, wastewater, storm drainage, gas, and telecommunications systems. Buried pipelines may rupture or become misaligned, roadways and bridges may settle or deform, and access routes needed for emergency response may be compromised. Industrial and commercial areas located on susceptible soils may face additional risks related to hazardous materials releases if tanks, pipelines, or containment systems are affected.

The earthquake scenario analyses for American Canyon indicate that strong to very strong ground shaking (MMI VII–VIII) is likely under credible seismic events. When combined with local liquefaction-prone soils, these shaking intensities increase the potential for widespread ground failure in susceptible areas. As a result, liquefaction poses a threat not only to individual structures but also to the city’s broader functionality and recovery following a major earthquake.

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Figure 1-17: Exposure Summary – City of American Canyon Earthquake Risk (M7.1 Hunting Creek–Berryessa) CAL OES SUBMITTAL - JUNE 2026
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Figure 1-18: Exposure Summary – City of American Canyon Earthquake Risk (M6.7 West Napa) CAL OES SUBMITTAL - JUNE 2026
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Figure 1-19: City of American Canyon Liquefaction Risk
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Slope Failure Hazard
Slope failure, including landslides, debris flows, and earth movement, poses a localized but notable hazard for the City of American Canyon due to the presence of steep terrain along the eastern edge of the city and surrounding foothills. Areas of higher landslide susceptibility are primarily located in the hillside and upland regions east of developed neighborhoods, where steeper slopes, weathered soils, and drainage features increase the likelihood of slope instability.

The Landslide Risk Exposure map, Figure 1-20, based on data from the California Geological Survey, identifies areas of low, moderate, and high landslide susceptibility. High-susceptibility areas are concentrated outside the City’s urban core, particularly in undeveloped or sparsely developed hillside terrain. These areas are more prone to slope failure during periods of prolonged or intense rainfall, which can saturate soil and reduce slope stability.

Exposure analysis indicates that slope failure risk affects a relatively small portion of American Canyon’s developed areas. Approximately 90 residents and 6 parcels are located within mapped high-susceptibility zones, with an estimated $8.3 million in building improvement and contents value exposed. No essential facilities, hazardous materials sites, high potential loss facilities, or major transportation and lifeline infrastructure are located within high-risk slope failure areas, limiting the potential for widespread community impacts.

Although overall exposure is limited, slope failure events can still result in localized damage to structures, roadways, and utilities, particularly where development occurs near steep slopes or drainage channels.

Landslides may also block access routes, disrupt emergency response, and increase sediment loads in downstream waterways. In addition, slope instability can be triggered or exacerbated by earthquake shaking, compounding risks during major seismic events.

Climate change may increase slope failure risk over time by contributing to more intense storm events and longer periods of soil saturation. Hillside areas east of American Canyon may experience increased erosion and slope movement under these conditions, emphasizing the importance of proactive planning and monitoring.

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Figure 1-20: Exposure Summary – City of American Canyon Slope Failure Risk CAL OES SUBMITTAL - JUNE 2026
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Drought Hazard
The National Drought Monitor provides drought data and maps nationally and on a localized, watershed scale. The National Drought Monitor is the product of 11 agencies, including the NDMC, NOAA and USDA, and is available at http://droughtmonitor.unl.edu/. The National Drought Monitor categorizes the level of drought from D0 through D4, with D4 being the highest “exceptional drought.” Table 1-13 depicts drought classifications and impacts from the level of drought occurrence in California, while Figure 1-21 shows a time series of the level of drought in Napa County from 2000 to 2026 according to the National Drought Monitor.

Drought is a recurring and long-term hazard for the City of American Canyon due to California’s Mediterranean climate, variable precipitation patterns, and increasing impacts from climate change.

Periods of prolonged below-average rainfall, reduced snowpack in the Sierra Nevada, and higher temperatures can significantly affect regional water supplies, ecosystems, and community resilience.

Although drought does not typically cause immediate physical damage like other hazards, its cumulative impacts can be widespread and long-lasting.

American Canyon relies on a combination of surface water and imported water supplies that are vulnerable to regional drought conditions. Extended drought periods can reduce available water supplies, increase demand during hotter and drier conditions, and place stress on water delivery systems. Drought conditions may also require implementation of mandatory water conservation measures, affecting residents, businesses, landscaping, and industrial operations.

Drought can exacerbate other natural hazards affecting American Canyon. Dry conditions increase vegetation stress and fuel loads, elevating wildfire risk in surrounding grasslands and open space areas.

Reduced soil moisture can also contribute to land subsidence, soil instability, and increased erosion during subsequent storm events. In addition, drought can degrade wetlands and riparian habitats along the Napa River and bayfront, reducing their natural flood attenuation and ecological functions.

Economic impacts of drought may include increased operational costs for businesses, reduced agricultural productivity in the surrounding region, and higher household expenses related to water use restrictions or rate adjustments. Vulnerable populations, including low-income households and elderly residents, may be disproportionately affected by higher utility costs and reduced access to cooling and water resources during extreme heat events associated with drought.

Climate change projections indicate that drought conditions in California are likely to become more frequent and severe, with longer dry periods punctuated by fewer but more intense storm events. These trends increase uncertainty in water supply reliability and place additional importance on long-term water resource planning, conservation, and resilience measures.

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Table 1-13: Drought Classifications and Impacts
Category Description Possible Impacts
D0
Abnormally
Dry
▪ Soil is dry; irrigation delivery begins early
▪ Dryland crop germination is stunted
▪ Active fire season begins
D1
Moderate
Drought
▪ Dryland pasture growth is stunted; producers give supplemental feed to cattle ▪ Landscaping and gardens need irrigation earlier; wildlife patterns begin to change ▪ Stock ponds and creeks are lower than usual
D2
Severe
Drought
▪ Producers increase water efficiency methods and drought-resistant crops ▪ Grazing land inadequate
▪ Fire season is longer, with high burn intensity, dry fuels, and large fire spatial extent, more fire crews on staff
▪ Lake- and river-based tourism declines; boat ramps close ▪ Trees are stressed; plants increase reproductive mechanisms; wildlife diseases increase
▪ Water temperatures increase; programs to divert water to protect fish begin ▪ River flows decrease; reservoir levels are low and banks are exposed D3
Extreme
Drought
▪ Federal water is not adequate to meet irrigation contracts; extracting supplemental groundwater is expensive
▪ Fire season lasts year-round; fires occur in typically wet parts of the state; burn bans are implemented
▪ Ski and rafting business are low; mountain communities suffer ▪ Low water levels impede fish migration and cause lower survival rates ▪ Wildlife encroaches on developed areas; little native food and water is available for bears, which hibernate less
▪ Water sanitation is a concern; reservoir levels drop significantly; surface water is nearly dry; flows are very low; water theft occurs
▪ Livestock need supplemental feed, cattle and horses are sold; little pasture remains ▪ Well and aquifer levels decrease; homeowners drill new wells D4
Exceptional
Drought
▪ Fire season is very costly; number of fires and areas burned are extensive ▪ Many recreational activities are affected
▪ Fields are left fallow; orchards are removed; vegetable yields are low; honey harvest is small; agricultural unemployment is high, food aid is needed ▪ Fish rescue and relocation begin; pine beetle infestation occurs; forest mortality is high; wetlands dry up; wildlife death is widespread; algae blooms appear ▪ Poor air quality affects health: greenhouse gas emissions increase as hydropower production decreases; West Nile outbreaks rise
▪ Water shortages are widespread; surface water is depleted; federal irrigation water deliveries are curtailed; water prices are extremely high; wells are dry, more and deeper wells are drilled; water quality is poor
Source: Adapted from U.S. Drought Monitor Drought Classifications and Impacts CAL OES SUBMITTAL - JUNE 2026
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Figure 1-21: Drought Severity Timeline 2000-2026
Severe Weather Hazard
Severe weather in the City of American Canyon is primarily associated with winter storm events, which can bring periods of heavy rainfall, localized flooding, and stormwater system impacts. The city is located in the southern portion of Napa County, where topography is generally flatter and less constrained than the northern valley and mountainous regions. As a result, while flooding can occur during intense rain events, the severity and extent of flooding is typically less pronounced than in the northern portions of Napa County, where steeper terrain and larger watersheds contribute to more significant flood hazards.

Heavy rainfall during winter months can lead to localized ponding, urban flooding, and increased runoff, particularly in low-lying areas, along roadways, and in areas with limited drainage capacity. Stormwater systems may become overwhelmed during high-intensity rainfall events, resulting in temporary street flooding and impacts to transportation. In addition, creeks and drainage channels within and near the city may experience elevated flows, which can contribute to localized flooding in adjacent areas.

Severe weather events may also produce secondary impacts, including debris accumulation in drainage systems, minor erosion, and disruption to transportation and daily activities. High winds associated with winter storms may result in downed trees or power outages, although these impacts are generally localized.

Compared to wildfire hazards, severe weather events in American Canyon tend to be short-duration and less destructive, but they can still affect infrastructure, mobility, and public safety.

Future climate conditions may influence the frequency and intensity of winter storm events, with projections indicating the potential for more intense rainfall over shorter durations, which could increase the likelihood of localized flooding. Continued maintenance of stormwater infrastructure, flood control systems, and drainage channels will be important to managing these risks.

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Extreme Heat Hazard
The City of American Canyon’s climate is influenced by its location within the Napa Valley and proximity to San Pablo Bay, which typically provides some moderation of temperature extremes. However, despite this marine influence, the City is increasingly experiencing periods of elevated temperatures, particularly during late summer and early fall when offshore flow conditions reduce coastal cooling effects. In recent decades, Napa has seen an increase in the frequency, duration, and intensity of extreme heat events, a trend that is expected to continue under changing climate conditions.

Historical & Regional Context
Although American Canyon has historically experienced a Mediterranean climate characterized by warm, dry summers and mild coastal influence, recent regional heat waves have demonstrated the city’s growing vulnerability to extreme heat. Statewide events, including those in 2017 and 2020, resulted in prolonged periods of high temperatures across inland portions of the Bay Area, including Napa Valley. During these events, temperatures in Napa exceeded typical seasonal norms and, in some cases, approached or exceeded 100°F for multiple consecutive days.

Napa’s valley setting contributes to heat retention, particularly during periods of high pressure and low wind, when warm air becomes trapped and nighttime cooling is limited. These conditions can result in extended heat events that persist over several days, increasing cumulative stress on residents, infrastructure, and natural systems. Unlike areas immediately adjacent to the bay, portions of Napa experience more pronounced temperature extremes due to reduced marine influence and localized topographic effects.

Climate projections indicate that the city is likely to experience a substantial increase in both the number of extreme heat days and warm nights over time. Extreme heat days, defined as those exceeding historically high temperature thresholds, are expected to become more frequent, while warm nights will reduce opportunities for overnight cooling, compounding heat-related stress on vulnerable populations.

According to the Cal-Adapt extreme heat days and warm nights tool using a medium emissions scenario (RCP 4.5), the City of American Canyon will likely experience a climate change-driven increase in extreme heat days from two days per year to 17 days per year by the end of the century. Over the same time period, the city is also likely to see an increase in warm nights from four days per year to 46 days per year Table 1-14 explains the extreme heat event thresholds for the City of American Canyon.

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Table 1-14: Cal-Adapt Extreme Heat Thresholds
Term Cal-Adapt Definition
Thresholds for
City of American
Canyon
Extreme
Heat Day
Defined as a day in a year when the daily maximum/minimum temperature exceeds the 98th percentile of daily maximum/minimum temperatures based on observed historical data from 1961-1990 between April and October.

99.2°F
Warm Night
Defined as a day in April through October when daily minimum temperature exceeds the 98th historical percentile of daily minimum temperatures, based on observed data from 1961-1990 between April and October.

60.2°F
Heat Wave Defined as four consecutive days or nights above the extreme heat / warm night threshold.
3 days ≥ 99.2°F
or 4 nights ≥

60.2°F
Source: Cal-Adapt Extreme Heat Days and Warm Nights Tool Impacts on Residents & Infrastructure
Extreme heat hazards impact American Canyon in several ways. Public health risks are the most immediate concern, with vulnerable populations such as seniors, young children, outdoor workers, medically fragile residents, and mobile home communities at elevated risk of heat-related illnesses. The city’s demographics, particularly its older adult population and concentration of seniors with disabilities, increase sensitivity to prolonged high temperatures.

From an infrastructure perspective, heat waves stress the power grid, raising the likelihood of blackouts that can leave residents without cooling options. Prolonged extreme heat can also damage roads, rail, and utilities, as well as strain HVAC systems in schools, businesses, and critical facilities. Parks, athletic fields, and outdoor programs may face closures due to unsafe conditions, impacting community services and recreation.

Cascading Effects
Extreme heat can contribute to and exacerbate other hazards within the City of American Canyon.

Prolonged high temperatures dry vegetation and increase wildfire risk in surrounding areas, while also contributing to degraded air quality, particularly during regional wildfire events. Heat can also intensify drought conditions by increasing evaporation rates and water demand, placing additional stress on local water resources.

Social and economic impacts are also associated with extreme heat. Households with limited financial resources may face challenges in maintaining adequate cooling or absorbing increased utility costs during prolonged heat events. These factors can contribute to disproportionate impacts on vulnerable populations and increase the need for targeted outreach and support.

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Climate Change Hazard
Average annual temperatures across most of California have already increased by more than 1°F, with some areas experiencing rises of over 2°F when comparing the 1901 to 1960 average to that of 1986 to 2016. Daily maximum temperatures—a key indicator of extreme heat—are projected to increase by 4.4°F to 5.8°F by 2050 and by 5.6°F to 8.8°F by 2100. Heat waves that impact public health, known as heat-health events, are also expected to intensify across the state. By 2050, these events are projected to last up to two weeks longer in the Central Valley and occur four to ten times more often in the Northern Sierra region (California Natural Resources Agency, 2022).

California is already experiencing significant impacts from climate change, including prolonged drought, a lengthened wildfire season, increased coastal flooding and erosion, and widespread tree mortality. The state has observed rising average temperatures, more extreme heat days, fewer cold nights, a longer growing season, and shifts in the water cycle, with less winter precipitation falling as snow. In addition, summertime fog has declined by approximately 33%, and both snowmelt and rainwater runoff are occurring earlier in the year (Cal OES, 2018).

Long-term trends indicate a 12% to 20% decline in fog across California from 1900 through projections to 2070. Climate experts suggest that warming temperatures reduce the ability of air masses to cool enough to produce fog, which plays a critical role in supporting California’s ecosystems (Grantham, Teodore; University of California, Berkeley, 2018).

The City of American Canyon is increasingly vulnerable to the long-term impacts of climate change, which function as hazard multipliers across the Napa Valley and broader North Bay region. American Canyon’s location close proximity to San Pablo Bay and surrounding upland areas, creates a complex climate setting that is sensitive to shifts in temperature, precipitation patterns, and seasonal variability. Projected changes in these conditions are expected to intensify existing hazards, including flooding, drought, extreme heat, wildfire, and slope instability.

American Canyon’s location near the Napa River and San Pablo Bay influences its local climate, though it still experiences periods of elevated temperatures during regional heat events. While marine influences can moderate temperatures at times, these effects may be reduced during offshore wind conditions or prolonged high-pressure systems, allowing heat to build across the area. As temperatures continue to rise, the frequency and duration of extreme heat events are expected to increase, placing additional stress on vulnerable populations such as older adults, children, outdoor workers, and residents without access to adequate cooling. Increased heat also drives higher energy demand, placing strain on the electrical grid and increasing the likelihood of service disruptions.

Sea Level Rise
The City of American Canyon is located at the southern end of Napa County adjacent to the Napa River and the San Pablo Bay shoreline, making it one of the few jurisdictions in the County directly exposed to sea level rise and tidal flooding hazards. Although much of Napa County is inland and not affected by coastal CAL OES SUBMITTAL - JUNE 2026
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processes, American Canyon’s proximity to the Bay places portions of the city at risk from rising sea levels, storm surge, and changes in tidal dynamics.

Sea level rise can lead to increased frequency and extent of tidal flooding, particularly in low-lying areas near the Napa River, wetlands, and shoreline zones. Areas that currently experience occasional flooding during high tides or storm events may be inundated more frequently as sea levels rise. In addition, higher baseline water levels can reduce the capacity of drainage systems to discharge stormwater, potentially leading to compound flooding during periods of heavy rainfall combined with high tides.

Critical infrastructure located near the Bay and river corridors may also be vulnerable to sea level rise. This includes transportation corridors, stormwater systems, wastewater infrastructure, and utilities, which may be affected by periodic inundation, corrosion, or reduced functionality over time. Wetlands and natural shoreline features may provide some buffering capacity, but they may also be impacted by rising water levels and changes in sediment dynamics.

Sea level rise may also contribute to secondary impacts, including saltwater intrusion into groundwater or soils, degradation of habitats, and increased maintenance needs for levees and shoreline protection systems. In areas where development is located near the shoreline or along tidal waterways, long-term exposure to rising water levels may affect land use, infrastructure planning, and property values.

Climate change projections for the San Francisco Bay Area indicate that sea levels are expected to continue rising over the coming decades, increasing the likelihood of both chronic tidal flooding and more severe impacts during storm events. As a result, the City of American Canyon may face increasing pressure to plan for adaptation strategies, including improvements to flood protection infrastructure, enhancement of natural buffers such as wetlands, and integration of sea level rise considerations into future development and capital improvement planning.

Drought & Water Reliability
Climate change is expected to result in more frequent and prolonged drought conditions across Napa County. While the City of American Canyon benefits from a combination of local and regional water sources, extended dry periods can reduce water availability, increase demand, and place stress on both surface water and groundwater systems. Reduced precipitation and earlier snowmelt in upstream watersheds may affect reservoir storage and seasonal water supply reliability.

Drought conditions also have broader environmental and hazard implications. Reduced soil moisture and vegetation stress increase susceptibility to wildfire in surrounding areas, while also affecting urban landscaping and tree canopy health within the city. Prolonged dry conditions may also impact local creeks and riparian systems, which play an important role in stormwater conveyance, habitat, and groundwater recharge.

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Precipitation, Storms & Flooding
Although total annual precipitation may not significantly increase, climate projections indicate that rainfall is more likely to occur in fewer, more intense storm events. These high-intensity storms, often associated with atmospheric river systems, increase the risk of riverine flooding along the Napa River as well as localized flooding in urban areas with constrained drainage systems.

Intense rainfall following extended dry periods can also increase the risk of erosion, localized slope instability, and debris flows, particularly in eastern hillside areas of American Canyon and along transportation corridors. These conditions can impact critical infrastructure, damage roadways, and disrupt emergency access. In addition, higher peak flows in the Napa River and its tributaries may exceed existing system capacity during extreme events, contributing to flooding beyond currently mapped floodplain boundaries.

Wildfire & Vegetation Change
Climate-driven increases in temperature and changes in precipitation patterns are expected to extend the wildfire season and increase fire risk in areas surrounding the City of American Canyon. While much of the city is urbanized, it is bordered by wildland/grassland and open space areas that are susceptible to wildfire.

Fires in surrounding areas can affect the city through evacuation impacts, degraded air quality, and strain on emergency services.

Changes in vegetation patterns, including increased tree mortality and shifts in species composition, may contribute to higher fuel loads over time. Even when wildfire does not directly impact the city, smoke and poor air quality can have significant public health consequences, particularly for sensitive populations.

Cascading Effects
Climate change amplifies interactions between hazards, creating compounding risks for the City of American Canyon. Extreme heat can worsen drought conditions and increase wildfire potential, while drought-stressed landscapes are more susceptible to erosion during intense storm events. Severe storms may damage infrastructure already stressed by heat or aging conditions, while flooding can disrupt transportation and utility systems needed for emergency response.

These cascading effects underscore the importance of integrating climate considerations into hazard mitigation planning, infrastructure investment, emergency preparedness, and community outreach. As climate conditions continue to evolve, proactive planning will be critical to reducing long-term risk and enhancing community resilience.

1.5.3 Climate Change Impacts & Vulnerable Populations
Climate change is expected to exacerbate many of the natural hazards affecting the City of American Canyon, increasing risks to populations that already face social, economic, or physical vulnerabilities.

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frequency of extreme heat are projected to intensify existing hazard conditions and create new challenges for public health, safety, and emergency response.

Certain populations in American Canyon are more likely to experience disproportionate impacts from climate-related hazards. Older adults, individuals with disabilities, low-income households, renters, and households with limited English proficiency may have reduced capacity to prepare for, respond to, and recover from climate-driven events. These groups may face barriers related to mobility, access to transportation, financial resources, housing stability, or timely access to emergency information.

Extreme heat presents a growing risk to vulnerable populations, particularly elderly residents, individuals with underlying health conditions, outdoor workers, and households without adequate cooling. Heat waves can increase the incidence of heat-related illness, strain electrical systems, and worsen air quality, especially when combined with wildfire smoke. Low-income households may be less able to afford cooling costs or make energy-efficient upgrades, increasing exposure during prolonged heat events.

Flooding and sea level rise disproportionately affect residents and workers in low-lying areas near the Napa River and bayfront. Vulnerable populations living or working in these areas may face greater risk of displacement, property damage, and disruption of access to essential services. Flood events can also impact transportation routes and utilities, creating additional challenges for individuals who rely on public transit, medical equipment, or nearby services.

Drought and water scarcity can place added burdens on vulnerable populations by increasing utility costs, limiting access to cooling and landscaping, and reducing the resilience of natural systems that provide flood protection and cooling benefits. For low-income households and fixed-income seniors, increased water and energy costs associated with drought and heat can compound financial stress.

Climate change may also increase the frequency and duration of poor air quality events, particularly from regional wildfires. Individuals with respiratory conditions, older adults, children, and outdoor workers are especially sensitive to smoke exposure. Limited access to air filtration, clean indoor environments, or protective equipment can further increase health risks for vulnerable populations.

1.5.4 Hazard Problem Statements
As part of the mitigation action identification process, the Planning Committee for each jurisdiction identified areas of concern (aka problem statements) for their respective facilities based on the risk assessment and vulnerability analysis, utilizing the RAMP mapping and static snapshot maps. Problem statements focused on the impact, victim, or threat that the hazard could create in the jurisdiction, as described in Table 1-15. Identifying common issues and weaknesses through these problem statements assisted the planning group in understanding the realm of resources needed for mitigation.

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corresponding problem statements that they address. Each problem statement is coded with a problem number for cross-referencing between Table 1-15 and Table 1-17 Table 1-15: City of American Canyon Hazard Problem Statements Problem No. Hazard Area of
Concern
Primary
Agency
Problem Description Related MA
ps-CC-AC-16 Climate
Change
Threat City of
American
Canyon
Sea level rise threatens American Canyon’s
critical shoreline facilities, including WWTP,
Public Works Yard, pump stations, and
Wetlands Edge Road, by increasing flood
frequency, storm surge impacts, and
infrastructure corrosion risk.
ma-CC-AC-10
ps-CC-AC-307 Climate
Change
Threat City of
American
Canyon
Climate change is expected to increase the
severity of extreme heat, drought, severe
weather, and flooding, exacerbating hazard
impacts on vulnerable populations and critical
infrastructure.
ma-DR-AC-20
ps-DF-AC-32 Dam Failure Victim City of
American
Canyon
Over 2,000 residents, more than 500 parcels,
and several critical facilities are located within
dam inundation zones associated with
Berryessa/Monticello, Napa Dam, Rector Creek,
and Chabot Dam, placing significant
downstream populations at life-safety risk.
ma-FL-AC-47,
ma-FL-NCo-55,
ma-FL-NCo-56,
ma-DF-NCo-120,
ma-DF-AC-215
ps-DF-AC-33 Dam Failure Threat City of
American
Canyon
Key access routes and major utility
infrastructure in American Canyon lie within
dam inundation areas, creating the threat of
road closures, service disruption, and potential
delays in emergency response during a dam
failure event.
ma-FL-AC-47,
ma-FL-NCo-55,
ma-FL-NCo-56,
ma-DF-NCo-120,
ma-DF-AC-215
ps-DR-AC-42 Drought Threat City of
American
Canyon
American Canyon relies almost entirely on
imported State Water Project supplies, which
fluctuate based on statewide hydrological
conditions. Increasing drought frequency
threatens water reliability, cost stability, and
the City’s long-term resilience.
ma-DR-AC-20,
ma-DR-NCo-24
ps-DR-AC-308 Drought Victim City of
American
Canyon
Drought impacts disproportionately affect
seniors, low-income households, and renters
who have limited control over water usage and
face heightened financial burdens during
drought surcharges or mandatory restrictions.
ma-DR-AC-20
ps-EQ-AC-69 Earthquake Victim City of
American
Canyon
All residents in American Canyon live in
severe shaking zones associated with a West
Napa Fault event, with renters, mobile home
residents, and seniors facing disproportionate
vulnerability.
ma-EQ-AC-32
ps-EQ-AC-70 Earthquake Victim City of
American
Canyon
More than 7,000 parcels, 200 critical facilities,
and nearly $7 billion in property value are
located in severe shaking zones, risking
widespread structural damage and extended
service outages.
ma-EQ-AC-32,
ma-EQ-AC-33
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Problem No. Hazard Area of
Concern
Primary
Agency
Problem Description Related MA
ps-EQ-AC-79 Earthquake Threat City of
American
Canyon
American Canyon’s water distribution system,
gas pipelines, and other underground utilities
are highly susceptible to rupture and service
failure during a major earthquake, increasing
the risk of fires, contamination, and extended
outages.
ma-EQ-AC-33
ps-FL-AC-120 Flood Victim City of
American
Canyon
Flooding along the Napa River and American
Canyon Creek can impact more than 1,600
residents in the 100- and 500-YR floodplains,
including multiple mobile home parks, with
tidal influence exacerbating flood depths and
drainage challenges.
ma-FL-AC-47,
ma-FL-AC-47,
ma-CC-AC-10,
ma-FL-AC-46
ps-FL-AC-122 Flood Impact City of
American
Canyon
Aging storm drainage systems and known
culvert backup locations create recurring flood
hazards during heavy rainfall and
atmospheric river events, especially when
combined with high tides.
ma-FL-AC-46,
ma-CC-AC-10
ps-FL-AC-123 Flood Victim City of
American
Canyon
Flooding threatens multiple critical
infrastructure facilities and can disrupt road
access, stormwater conveyance, and
community lifelines due to culvert backups
and tidal surge interactions.
ma-FL-AC-47,
ma-CC-AC-10
ps-HH-AC-310 High Heat Impact City of
American
Canyon
Extreme heat often triggers PSPS events or
power outages from high demand during peak
times.
ma-HH-AC-216
ps-HH-AC-311 High Heat Victim City of
American
Canyon
Extreme heat events place seniors, medically
vulnerable residents, outdoor workers, and
low-income households at elevated risk of
heat-related illness.
ma-HH-AC-216
ps-HH-AC-312 High Heat Threat City of
American
Canyon
The number of extreme heat days and warm
nights and duration of heat waves is
anticipated to increase with climate change.
ma-HH-AC-216
ps-HH-AC-313 High Heat Threat City of
American
Canyon
The city lacks back-up power for many cooling
centers, limiting shelter options and capacity
during heat events.
ma-HH-AC-216
ps-SW-AC-143 Severe Weather Impact City of
American
Canyon
Severe winter storms and heavy rain events
cause roadway flooding, downed trees, power
outages, and PSPS-related disruptions,
affecting mobility, safety, and essential
services throughout the city.
ma-SW-NCo-81,
ma-SW-NCo-82,
ma-SW-AC-121,
ma-SW-AC-214
ps-SW-AC-309 Severe Weather Victim City of
American
Canyon
Medically dependent residents, seniors, and
households without backup power are
disproportionately impacted by outages during
severe storms, including high wind, PSPS
events, and flooding from heavy rain.
ma-SW-AC-121,
ma-SW-AC-214
ps-SF-AC-314 Slope Failure Impact City of
American
Canyon
Slides, erosion, and other slope failures can
block roads and damage recreational trails,
limiting use and often cutting off access for
maintenance (e.g., for PG&E).
ma-SF-AC-217
ps-SF-AC-315 Slope Failure Victim City of
American
Canyon
Slope failures can negatively impact water
quality and cut off access for ranchers and can
reduce recreation options for trail users.
ma-SF-AC-217
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Problem No. Hazard Area of
Concern
Primary
Agency
Problem Description Related MA
ps-SF-AC-316 Slope Failure Threat City of
American
Canyon
Heavy rain and earthquake events can trigger
major slope failures in the hilly areas in and
around the city.
ma-SF-AC-217
ps-WF-AC-173 Wildfire Victim City of
American
Canyon
Residents living in moderate to high wildfire
intensity zones remain at risk, and vulnerable
populations like seniors and those without
personal vehicles may face challenges
evacuating during fast-moving fires.
ma-WF-AC-86,
ma-WF-NCo-90
ps-WF-AC-174 Wildfire Threat City of
American
Canyon
Critical facilities, utility corridors, and hillside
vegetation create the threat of rapid wildfire
spread toward populated areas, particularly in
areas lacking defensible space or redundant
access routes.
ma-WF-AC-86
ps-WF-AC-175 Wildfire Impact City of
American
Canyon
Legacy High School and the Water Treatment
Plant are located in high wildfire intensity
zones, where smoke, embers, and fire spread
can disrupt education, water treatment
operations, and air quality.
ma-WF-AC-86
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1.6 Mitigation Strategy
This section provides the framework for how the City of American Canyon will reduce hazard risk within its jurisdiction while supporting the broader goals of the Napa County MJHMP. It includes an overview of existing capabilities, opportunities to strengthen resilience, and the city’s prioritized mitigation actions.

Together, these elements demonstrate how American Canyon integrates hazard awareness into its planning and development processes while contributing to a coordinated countywide approach.

Within the Napa County MJHMP, the mitigation strategy serves as the roadmap for future hazard mitigation efforts. For American Canyon, the strategy outlined in this annex reflects the outcomes of the countywide planning process while also addressing the city’s unique risks, priorities, and community needs. The strategy is designed to reduce vulnerabilities identified in the risk assessment, including the problem statements developed for flooding, earthquakes and liquefaction, slope failure, wildfire, drought, severe storms, extreme heat, and climate change.

Mitigation actions identified in this annex include both policy-based and project-based initiatives, with an emphasis on integrating resilience into land use planning, infrastructure investments, and community programs. Actions are structured to align with FEMA’s requirements and to coordinate with existing city, county, and regional planning mechanisms. Each action identifies responsible parties, potential funding sources, and the resources needed for implementation.

For American Canyon, this strategy provides a framework for strengthening resilience by combining cityled initiatives, such as infrastructure improvements, building code enforcement, and community preparedness, with regional coordination through the MJHMP. By advancing these efforts in alignment with the General Plan and other local planning documents, American Canyon enhances its ability to reduce hazard risk while supporting long-term community safety, sustainability, and economic stability.

The subsections that follow describe these elements in detail:
▪ Sections 1.6.1, Capabilities and Opportunities, provides a summary of the city’s capacity to address natural hazards.
▪ Section 1.6.2, Mitigation Action Plan, presents American Canyon’s prioritized actions to guide implementation in coordination with countywide strategies. ▪ Section 1.6.3, Status of Previous Mitigation Actions, provides a summary of all previous actions and their current status, whether completed, cancelled, or revised.

Aligning the Action Plan
This section connects American Canyon’s mitigation actions with its existing capabilities and areas for growth. Capability assessments are a required element of hazard mitigation planning under the Disaster Mitigation Act of 2000 and FEMA’s 2023 guidance, ensuring that actions are realistic, achievable, and aligned with available resources.

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The section begins with a summary of American Canyon’s capabilities across four areas: planning and regulatory, administrative and technical, fiscal, and education and outreach. This overview highlights the tools and strengths that the district already uses to reduce hazard risk. The section then provides a detailed analysis of each capability area, identifying both current practices and opportunities to expand resilience.

1.6.1 Capabilities & Opportunities
This section provides a detailed assessment of the city’s current capabilities to support hazard mitigation, as well as future opportunities. This consists of describing how the city is planning for hazards and growth and a summary of its existing capabilities and the potential for enhancement.

Planning for Hazards & Growth
As a general law city, the City of American Canyon manages growth within the framework of California’s comprehensive planning, zoning, subdivision, and environmental regulations. Much of the City’s developable land has already been urbanized, and remaining growth is largely directed toward infill development, redevelopment, and planned buildout within the existing urban footprint. American Canyon is bordered by the Napa River and bayfront wetlands to the west and hillside terrain to the east, which constrains outward expansion and concentrates future development in areas already subject to natural hazards.

This development pattern places portions of the city’s population, infrastructure, and economic assets within areas exposed to hazards such as riverine and tidal flooding along the Napa River, dam inundation zones, strong earthquake ground shaking and liquefaction, and extreme heat and drought conditions.

Industrial and commercial areas near the river corridor and residential neighborhoods in low-lying areas are particularly sensitive to flooding and sea level rise, while hillside areas east of the city face localized risks related to slope instability and wildfire exposure.

Hazard vulnerability is addressed through coordination with the city’s General Plan, particularly the Safety Element, which integrates hazard information into land use decisions, infrastructure planning, and development review. This approach ensures that growth and redevelopment consider site-specific risks and incorporate appropriate mitigation measures, such as flood-resilient design, geotechnical stabilization, and emergency access planning. Integration of hazard considerations into long-range planning also supports compliance with state and federal hazard mitigation requirements and strengthens the City’s eligibility for disaster recovery and resilience funding.

Climate change is expected to intensify several of the hazards affecting American Canyon, including flooding influenced by sea level rise, more extreme precipitation events, prolonged drought, and increasing extreme heat. As growth continues within constrained and hazard-exposed areas, resilience must be embedded into every phase of planning and development. Growth management in American Canyon therefore emphasizes sustainable building practices, water conservation, protection of natural floodplain functions, and climate-adaptive infrastructure, ensuring that future development and redevelopment reduce, rather than exacerbate, existing hazard risks and support long-term community resilience.

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Long-Range Planning & Growth Management
Long-range planning and growth management policies play a central role in limiting hazard exposure in American Canyon. The city’s General Plan establishes the overall land use pattern, directs growth toward areas that can be safely and efficiently served by infrastructure, and discourages development in areas subject to significant natural hazards where feasible.

Growth in American Canyon has largely occurred within an established urban footprint, with an emphasis on infill development, redevelopment, and planned expansion areas that are supported by existing transportation, utility, and emergency services. This approach helps reduce the need for development in hazard-prone areas such as floodplains, steep slopes, and wildfire-prone wildland–urban interface locations. Where development does occur near hazard areas, planning policies emphasize hazard-aware site design, infrastructure resilience, and emergency access.

Long-range planning efforts also account for future climate conditions, recognizing that sea level rise, extreme heat, drought, and more intense storm events may alter hazard profiles over time. Incorporating these considerations into growth management helps ensure that future development does not increase vulnerability or place undue strain on emergency response and public services.

Building Codes & Development Standards
American Canyon’s development strategies combine comprehensive planning frameworks with robust regulatory measures to guide growth while reducing risks from natural hazards. Building codes play a central role in this approach. Nationally, continual improvements to building codes since 1990 have added only about one percent to construction costs while greatly improving disaster resilience (National Institute of Building Sciences, 2019). In California, building codes are among the most stringent in the world, setting minimum standards that safeguard against hazards such as earthquakes, flooding, wildfire, landslides, and severe weather. American Canyon enforces these standards locally, providing a strong foundation for resilient construction.

The city is required to regularly update its development regulations to reflect the California Building Code (CBC), which is revised every three years and was most recently updated in 2025. The CBC establishes some of the world’s highest construction standards, ensuring occupant safety in the face of natural hazards.

Climate change is also addressed through adoption and updating of the California Green Building Standards (CALGreen) and Energy Codes, which integrate energy efficiency, sustainable design, and climate adaptation measures. In addition, American Canyon participates in the National Flood Insurance Program (NFIP), requiring that all new development in designated flood hazard areas meet FEMA’s minimum flood protection standards.

Through these building and development regulations, American Canyon ensures that new development in hazard-prone areas is either restricted or subject to strict hazard-mitigation requirements. Where development is allowed, codes emphasize reducing exposure and vulnerability through appropriate siting, advanced construction techniques, emergency access, and defensible space. For example, new CAL OES SUBMITTAL - JUNE 2026
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construction in the wildland–urban interface (WUI) must comply with fire-resistant building materials and vegetation management requirements under the California Fire Code.

Beyond code enforcement, American Canyon integrates these mandates into broader local planning frameworks, including the General Plan and HMP This alignment ensures that growth management, environmental review, and hazard mitigation strategies collectively address emerging risks from wildfire, drought, flooding, extreme heat, and severe weather intensified by climate change.

California Environmental Quality Act (CEQA) & Hazard Mitigation The California Environmental Quality Act (CEQA) requires General Plans, Specific Plans, and major development projects to evaluate hazards such as coastal flooding, bluff erosion, seismic risk, and wildfire.

Environmental documents must identify these risks and propose mitigation measures, which may include setbacks from hazard-prone areas, infrastructure upgrades, evacuation planning, or restrictions on development in high-risk zones.

Regional and state public safety planning frameworks that inform development review in American Canyon include the State Seismic Hazards Mapping Act, the California Environmental Quality Act (CEQA) and its Guidelines, California Noise Insulation Standards (Title 24), and the Federal Emergency Management Agency (FEMA) Flood Insurance Program. Together, these programs establish requirements for evaluating and mitigating environmental and hazard-related impacts associated with development.

Under CEQA, residential projects that require discretionary approval from the city are subject to environmental review concurrently with the approval process. While CEQA review can add time to development and is therefore considered a potential constraint to housing production, much of American Canyon’s remaining vacant and developable land has already undergone environmental review through Program Environmental Impact Reports (PEIRs) prepared as part of adopted specific plans. These PEIRs streamline subsequent project-level CEQA review by identifying environmental impacts and mitigation measures in advance, allowing later residential projects to tier from or rely on existing CEQA documents.

Projects that deviate from the assumptions or scope of adopted specific plans may also tier from previously certified CEQA analyses, where appropriate.

Recent updates to CEQA standards have also changed how transportation and air quality impacts are evaluated. Transportation impacts are no longer assessed using Level of Service (LOS), which measured vehicle delay, but instead rely on Vehicle Miles Traveled (VMT) as the primary metric. This shift emphasizes reducing vehicle travel and associated emissions rather than roadway congestion.

In addition, updated Bay Area Air Quality Management District (BAAQMD) greenhouse gas (GHG) thresholds, adopted in April 2022, require changes to how GHG impacts are analyzed in CEQA documents. Under these standards, plans or projects within BAAQMD jurisdiction must either demonstrate consistency with an adopted, qualified local Climate Action Plan or incorporate specific project features, including all-electric buildings, a minimum reduction in VMT, and electric vehicle infrastructure meeting CalGreen Tier 2 requirements.

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Although LOS is no longer used for CEQA compliance, the city continues to use LOS analysis as a non-CEQA planning tool to evaluate roadway operations, support infrastructure planning, and ensure that key transportation corridors function effectively and meet community expectations. Together, CEQA and related regulatory frameworks play a critical role in integrating hazard mitigation, climate adaptation, and sustainability considerations into development and long-range planning decisions in American Canyon.

By integrating hazard analysis into the development review process, CEQA helps ensure that future growth in American Canyon is designed with resilience and long-term community safety in mind.

Development & Hazard Considerations
Development in the City of American Canyon occurs within a physical and regulatory context shaped by natural hazards, environmental constraints, and long-term growth management policies. As a general law city operating under California planning and environmental regulations, American Canyon evaluates development proposals with consideration for hazard exposure, public safety, infrastructure capacity, and long-term resilience. This integrated approach helps ensure that new development and redevelopment do not increase risk to people, property, or critical systems.

Much of the city’s remaining development potential lies within areas that are already urbanized or planned through adopted specific plans. As a result, development often occurs in proximity to known hazard areas, including floodplains along the Napa River, dam inundation zones, liquefaction-prone soils, and areas exposed to strong seismic shaking and extreme heat. Rather than avoiding development entirely in these locations, the city emphasizes risk-informed site planning, design, and construction standards to reduce vulnerability and limit potential impacts.

Flood hazards are addressed through enforcement of flood plain management regulations, participation in the National Flood Insurance Program, and incorporation of flood-resilient design measures for development in or near mapped flood hazard areas. These measures may include elevating structures, protecting utilities, maintaining flood conveyance, and avoiding critical facilities in the highest-risk locations. Development decisions also consider future flood conditions associated with sea level rise and more intense storm events.

Seismic hazards are a key consideration in development review due to the City’s location within the seismically active San Francisco Bay Area. Projects are required to comply with state seismic design standards and, where appropriate, conduct site-specific geotechnical investigations to address ground shaking, liquefaction, and slope stability. These requirements help reduce structural damage and protect infrastructure during earthquake events.

Wildfire, slope failure, and extreme weather hazards are also considered during development review, particularly in areas near the eastern hills, open space, and transportation corridors. Development standards related to defensible space, access, drainage, and emergency response are used to minimize risk and support safe evacuation and emergency operations.

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The CEQA provides a framework for identifying hazard-related impacts at the project level and requiring feasible mitigation measures. Through CEQA review, the city evaluates whether proposed development would expose people or structures to significant risks from natural hazards and ensures that appropriate avoidance, design, or mitigation measures are incorporated into project approvals.

Capabilities & Opportunities Assessment
To develop a realistic and actionable mitigation strategy, it must account for existing jurisdictional capabilities and what future opportunities there are to enhance those capabilities for purposes of hazard mitigation. This section provides an assessment of the City of American Canyon’s existing capabilities and future opportunities, including planning and regulatory, administrative and technical, fiscal, and public outreach and education capabilities. This assessment also identifies opportunities to integrate this MJHMP into future planning, policies, or programs to weave mitigation efforts into daily operations and address hazard problems wholistically. Capabilities are categorized into four groups and include various mechanisms.
▪ Planning and Regulatory Capabilities: Existing long-range plans, emergency response plans, hazard-specific plans, land use policies, and building and development standards. ▪ Administrative and Technical Capabilities: Available expertise in emergency services, engineering, grant management, and community planning.
▪ Fiscal Capabilities: Budgetary capacity, taxing authority, grants, and other funding mechanisms that can support mitigation projects.
▪ Outreach and Education Capabilities: Existing programs for providing technical assistance, community education, public warnings, and stakeholder engagement.

A full description of the process used to develop the capabilities assessment is provided in Volume 1, Section

2.3.3. This capabilities and opportunities assessment for American Canyon lists the various types of capabilities along with how they have been, currently are, or will in the future be integrated into hazard mitigation planning efforts. The three “HMP Integration” columns that identify the capability’s status and usage are color-coded with green, yellow, or orange shading to communicate the following:
▪ Status: If the capability is present at all and what level of use it has generally. ▪ Current Mitigation Use: If the capability is currently being used in mitigation efforts, specifically, and at what level.
▪ Future Opportunity: If there is a future opportunity to integrate the capability into mitigation efforts and at what level.

Summary of Capabilities & Opportunities
This Capabilities and Opportunities Assessment for American Canyon summarizes the various types of capabilities it has for hazard mitigation currently. The assessment also identifies opportunities to integrate, CAL OES SUBMITTAL - JUNE 2026
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expand, and improve the city’s capabilities for future hazard mitigation. Table 1-16 provides a comprehensive list of capabilities and identifies the current status, current mitigation use, and future opportunities.

Planning & Regulatory
The City of American Canyon has strong planning and regulatory capabilities that support hazard risk reduction and resilient development. The city enforces the California Building Code (Title 24) and locally adopted ordinances that address floodplain management, fire safety, stormwater control, water conservation, and development in inundation and hillside areas. These regulations are integrated into zoning, subdivision, and site plan review processes, ensuring that hazard considerations are addressed during development reviews.

Growth management is guided by policies in the city’s General Plan, with updated hazard, climate change, and environmental justice policies being incorporated through the ongoing 2040 General Plan update.

Capital investments are prioritized through the Capital Improvements Program (CIP), which supports resilient infrastructure for water, storm drainage, transportation, and public services.

American Canyon maintains several hazard reduction programs, including stormwater management and erosion control, water conservation, and public outreach through the ReadyAC emergency preparedness webpage. The city also promotes non-structural earthquake preparedness and household-level mitigation actions.

The city participates in the National Flood Insurance Program (NFIP) and enforces local floodplain management regulations supported by current FEMA flood mapping and elevation certificate records. While flood preparedness information is available, flood insurance education is limited, and the City does not currently participate in FEMA’s Community Rating System (CRS), representing a future opportunity for enhanced flood risk reduction.

Future integration of the MJHMP will occur through various processes and mechanisms outlined across multiple mitigation actions (Table 1-17). Key opportunities for future hazard mitigation integration with the city’s existing planning mechanisms include using the updated risk assessment, flood hazard data, and projected climate change impacts to inform implementation of the Flood Mitigation Support Program (maFL-AC-46), Flood Notification System Improvement (ma-FL-AC-47), and Stormwater Drainage Resilience Program (ma-SW-AC-121).

Administrative & Technical
The City of American Canyon has strong administrative and technical capacity to support hazard mitigation planning, implementation, and coordination. Core planning, engineering, and development review functions are housed within the Community Infrastructure and Development (CID) Department, including the Planning & Zoning, Public Works, and Building Divisions. These staff provide expertise in land use planning, development review, infrastructure design, and enforcement of building and safety standards.

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The city has access to qualified personnel for key hazard mitigation functions, including community planning, land development review, construction engineering, natural hazards analysis, transportation planning, and resilience planning. The Building Division provides building code administration, and the City Manager serves as the Floodplain Administrator and Director of Emergency Services, ensuring direct coordination between planning, emergency management, and floodplain compliance. Fire prevention and wildfire mitigation functions are supported by the American Canyon Fire Protection District through the Fire Marshal.

While the City does not have dedicated staff for public outreach, GIS, or grant management, these functions are addressed through shared responsibilities across departments and through coordination with regional partners such as Napa County, which provides GIS support. This shared staffing approach effectively supports current mitigation activities but represents an opportunity for enhancement as hazard mitigation, climate adaptation, and grant funding efforts expand.

Warning Systems & Services
The City of American Canyon has strong warning and emergency communication capabilities to alert residents, businesses, and visitors of hazardous conditions and emergency situations. The city utilizes the Alert Napa County emergency notification system as its primary platform for disseminating time-sensitive warnings related to natural hazards, evacuations, sheltering, and public safety incidents.

Emergency information is also communicated through city and partner social media channels, which provide rapid updates and situational awareness during evolving incidents. These electronic communication methods are supplemented by non-electronic outreach, including door-to-door notifications when necessary, and emergency vehicle sirens used by police and fire agencies to warn the public in affected areas.

This multi-channel approach helps ensure redundancy and increases the likelihood that critical information reaches residents with varying access to technology or communication needs. Warning systems support response to a range of hazards, including flooding, wildfire, earthquakes, extreme weather, and power shutoff events.

Fiscal
The City of American Canyon has moderate to strong fiscal capacity to support hazard mitigation through a combination of local revenues, fees, grants, and long-term financing tools. These funding mechanisms support infrastructure maintenance, capital improvements, and implementation of hazard mitigation measures identified in city plans and programs.

The city collects utility fees for water, recycled water, and sewer services, which help fund infrastructure upgrades that support drought resilience, flood protection, and system reliability. System development and impact fees are also a key funding source and are assessed for traffic, housing, water and wastewater capacity, parks and recreation, civic facilities, General Plan implementation, and fire district mitigation.

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These fees help ensure that new development contributes to infrastructure needed to safely accommodate growth.

American Canyon has the authority to use general obligation bonds and special tax or revenue bonds to finance large capital projects, providing flexibility to fund hazard mitigation–related infrastructure improvements when voter approval or project-specific revenues are available. The city also adopts a Capital Improvement Program (CIP) tied to the annual budget, which prioritizes investments in infrastructure that supports public safety and resilience.

Additional funding sources include Community Development Block Grants (CDBG), which can be used for hazard-related housing rehabilitation and infrastructure improvements, particularly for vulnerable populations. While special-purpose taxes and benefit assessments are not consistently used, the City has the authority to pursue voter-approved tax measures for specific purposes, such as public safety or infrastructure, representing a future opportunity to expand mitigation funding.

Education & Outreach
The City of American Canyon has strong education and outreach capabilities that support public awareness, preparedness, and risk reduction for natural hazards. The city maintains a dedicated emergency preparedness webpage, ReadyAC, which centralizes information on alerts, evacuations, flooding, wildfire, earthquakes, power shutoffs, and other hazards. This resource serves as the primary hub for hazard-related public information.

The city actively uses social media platforms, including City websites, Facebook, Instagram, Nextdoor, and YouTube, to disseminate emergency information, preparedness messaging, and real-time updates during incidents. These digital tools are complemented by participation in annual public safety and preparedness events, such as the Great California ShakeOut and Ready Napa County initiatives.

American Canyon supports community-based preparedness through the Community Emergency Response Team (CERT) program and partnerships with regional organizations, including local Fire Safe Councils and the Napa Communities Firewise Foundation. The city also collaborates with the Napa County Resource Conservation District, which provides outreach related to wildfire, drought, and other environmental hazards.

City staff are available to respond to public inquiries and provide technical assistance related to hazard preparedness, floodplain regulations, and development standards through phone, email, and web-based requests. While hazard information is primarily disseminated online, printed materials and library-based resources are used on a limited basis, representing an opportunity for expanded outreach to residents with limited digital access.

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ASSESSMENT LEGEND
HMP Integration
Status Current Mitigation Use Future Opportunity
Currently in use or present. Used widely for mitigation. Opportunity to expand and integrate. (Sort of) Seldomly used or limited
presence.

Limited use in mitigation
planning.

Limited opportunity to expand and
integrate.
(No) Not present or available. Not used in mitigation planning. No opportunity to expand or integrate.

Table 1-16: City of American Canyon Capabilities and Opportunities Assessment HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Planning and Regulatory
Capabilities
Construction and Future
Development Regulations
Building Codes
Green Green Green California Building Code (California Code of Regulations, Title 24) adopted under Title 16
BCEGS Rating 0 0 0
Public Protection (ISO Class) 0 0 0
Hazard-Related Development
Standards
Green Green Green
Floodplain Management Regulations (Ch. 8.16), Fire
Regulations (Ch 8.08), Stormwater and Pollution
Discharge Control (Ch. 14.28), Water Conservation
(Ch. 13.14), Subdivision including standards for
inundation and steep slope areas (Title 18), and
Zoning (Title 19) including standards for water
efficiency, floodplains, and hillsides
Zoning Ordinance
Green Green Green Title 19 including standards for water efficiency, floodplains, and hillsides
Hazard-Specific Ordinance
Green Green Green
Floodplain Management Regulations (Ch. 8.16),
Stormwater and Pollution Discharge Control (Ch.

14.28), and Water Conservation (Ch. 13.14)
Growth Management Ordinance
Green Green Green
Growth managed through policies in 1994 General
Plan Land Use and other Elements (amended 2021);
2040 GP update in progress includes updated
growth management policies
Hazard Reduction Programs
(Annually Conducted)
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HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Capital Improvements Program
(CIP) or Plan Green Green Green
FY 2025-29 CIP and budget covers developing and
maintaining infrastructure services to support
sustainable growth
Erosion/Sediment Control
Program Green Green Green Ch 14.28 Stormwater and Pollution Discharge Control
Hazard-Related Public Outreach
Program Green Green Green
Emergency preparedness webpage (ReadyAC)
centralizes hazard information (alerts, evac,
flooding, wildfire, earthquakes, PSPS)
Urban Water Management Plan
Green Green Green 2020 UWMP maintained by Utilities & Services Dept Stormwater Management
Program (Annual Inspections) Green Green Green Ch 14.28 Stormwater and Pollution Discharge Control, enforced by Utilities & Services Dept
Seismic Safety Program (Nonstructural) Green Green Green ReadyAC webpage provides info and checklists for earthquake preparedness
Earthquake Modernization Plan
(Building Safety)
Green Green Green
2040 General Plan includes updated Safety Element
policies and actions to address seismically unsafe
buildings; also addressed enforcement of the
California Building Code with local seismic
amendments
Hazard Plans
General Plan Safety Element
Green Green Green
1994 General Plan Flood Hazards and Geology
Elements (amended 2021); 2040 GP includes new
consolidated Safety Element encompassing
wildfire, flood, geologic, seismic, and climate
change hazards
Site Plan Review Requirements Green Green Green Ch 19.41 design permit review process General Plan Environmental
Justice Element Green Green Green
Not addressed in 1994 General Plan (amended 2021);
2040 GP update in progress includes new
Environmental Justice Element
Community Wildfire Protection
Plan (CWPP) Green Green Green 2021 Napa County CWPP
Economic Development Plan
Green Green Green 1994 General Plan Economic Development Element (amended 2021); 2040 GP includes updated element
Floodplain Management Plan
Green Green Green
1994 General Plan Flood Hazards Element
(amended 2021); 2040 GP includes new consolidated
Safety Element encompassing flood; Ch 8.16
Floodplain Management Regulations
Stormwater Management Plan
Green Green Green
2040 General Plan includes Utilities and
Environment, Parks & Recreation Elements that
address storm drainage and water quality; Ch 14.28
Stormwater and Pollution Discharge Control,
enforced by Utilities & Services Dept
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HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Emergency Operations Plan
Green Green Green 2017 Napa County EOP, City of American Canyon Annex
Climate Action Plan
Green Green Green Napa County Regional Climate Action and Adaptation Plan (RCAAP)
Climate Vulnerability
Assessment Green Green Green Napa County RCAAP includes assessment Urban Greening Plan
Green Green Green
No standalone plan; policies established in 1994
General Plan Natural & Historic/Cultural Resources
Element (amended 2021); 2040 GP includes new
Environment, Parks & Recreation Element that
covers urban forestry
Ground Water Management
Planning / Plans
Green Green Green
Maintained by Napa County Groundwater
Sustainability Agency; 2020 UWMP maintained by
Utilities & Services Dept; Ch. 13.14 Water
Conservation
National Flood Protection
Program (NFIP)
Floodplain Management
Regulations Green Green Green Ch 8.16 Floodplain Management Regulations Flood Insurance Education and
Technical Assist. Yellow Yellow Green
Flood preparedness info provided through ReadyAC
webpage, but no insurance education; staff
available for technical assistance
Flood Insurance Study Green Green Green 2016 FEMA FIS 06055CV000C Elevation Certificates
Green Green Green Maintained by Building Division in Community Infrastructure & Development (CID) Dept
Flood Hazard Mapping / ReMapping Green Green Green FEMA FIRMs 2008 and 2016 Community Rating System (CRS)
Orange Orange Yellow Does not currently participate; future opportunity but limited staff capacity
Administrative and
Technical
Community Planning and
Development Services
Community Planner
Green Green Green Community Infrastructure & Development Dept, Planning & Zoning Division
Planner/Engineer (Land
Development) Green Green Green Community Infrastructure & Development Dept, Planning & Zoning Division
Engineer/Professional
(Construction)
Green Green Green Community Infrastructure & Development Dept, Public Works Division
Planner/Engineer/Scientist
(Natural Hazards) Green Green Green Community Infrastructure & Development Dept, Public Works Division
Transportation Planner
Green Green Green Community Infrastructure & Development Dept, Public Works Division
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HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Resiliency Planner
Green Green Green Community Infrastructure & Development Dept, Planning & Zoning Division
Building Code Official (Full time
or Augmented) Green Green Green Community Infrastructure & Development Dept, Building Division
Floodplain Administrator Green Green Green City Manager Fire Marshal Green Green Green American Canyon Fire Protection District Dedicated Public Outreach
Personnel Green Green Green City Manager's Office, Communications Team GIS Specialist and Capability
Yellow Yellow Green No dedicated staff; shared across departments and supported by Napa County GIS; future opportunity
Emergency Manager
Green Green Green City Manager designated Director of Emergency Services
Dedicated Grant Manager, Writer,
or Specialist Yellow Yellow Green No dedicated staff; shared across departments; future opportunity
Other N/A N/A N/A
Warning Systems/Services
General
Green Green Green
Alert Napa County system, social media posts, non
electronic communications, and emergency vehicle
sirens
Flood
Green Green Green
Alert Napa County system, social media posts, non
electronic communications, and emergency vehicle
sirens
Tornado
Green Green Green
Alert Napa County system, social media posts, non
electronic communications, and emergency vehicle
sirens
Wildfire
Green Green Green
Alert Napa County system, social media posts, non
electronic communications, and emergency vehicle
sirens
Geological Hazards #N/A #N/A #N/A #N/A
Fiscal Capabilities
Financial Resources for
Hazard Mitigation
Levy Taxes for Specific Purposes
Yellow Yellow Yellow
Not consistently applied, but can place special tax
measures on ballot for specific purposes (e.g., sales
tax for public safety)
Utilities Fees Green Green Green Water, recycled water, and sewer fees Benefit assessments Orange Orange Yellow Not currently in use; future opportunity Community Development Block
Grants Yellow Yellow Green Received via HUD; can support hazard-related housing rehabilitation and infrastructure
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HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
System Development Fee
Green Green Green
Impact fees collected for Traffic Impact, Housing
Nexus, Water and Wastewater Capacity, Parks &
Recreation Impact, Civic Facility, General Plan
Impact, and Fire District Mitigation
General Obligation Bonds to
Incur Debt Green Green Green General obligation bonds are available financing tools
Special Tax Bonds to Incur Debt
Green Green Green Special tax/revenue bonds are authorized for specific projects
Withheld Spending in HazardProne Areas Green Green Green General Plan policies restrict development in hazard-prone areas
Stormwater Service Fees Green Green Green Grading and Drainage Plan review fees Capital Improvement Project
Funding Green Green Green CIP adopted; tied to annual budget Education / Outreach
Capabilities
Education/Outreach
Resources
Website Dedicated to Hazard
Topics Green Green Green
Emergency preparedness webpage (ReadyAC)
centralizes hazard information (alerts, evac,
flooding, wildfire, earthquakes, PSPS).

Dedicated Social Media
Green Green Green Active Facebook, Instagram, Nextdoor, and YouTube accounts
Local Citizen Groups That
Communicate Hazard Risks Yellow Yellow Green Informal local groups provide hazard information Hazard Info. Avail. at Library/
Planning Desk Yellow Yellow Green Hazard info available via City website and partner websites
Annual Public Safety Events
Green Green Green Participates in Earthquake ShakeOut, Ready Napa County, and other regular events
Ability to Field Public Tech.

Assistance Requests Green Green Green
Staff respond to inquiries via phone, email, and web
forms; department-specific technical assistance
available
Public Safety Newsletters or
Printed Outreach Green Green Green Monthly Public Safety Newsletter Community Emergency
Response Team (CERT) Green Green Green American Canyon CERT Fire Safe Councils
Green Green Green Fire Safe Council and others through Napa Communities Firesafe Foundation
Firewise Orange Orange Green Actively pursuing with Napa Firewise StormReady Orange Orange Green Not currently designated Resource Conservation Districts
Green Green Green
Napa County RCD provides outreach on wildfire,
drought, and other hazard topics; City participates
through partnerships
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HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Other N/A N/A N/A
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1.6.2 City of American Canyon Mitigation Action Plan
American Canyon’s
mitigation actions were
developed through a
collaborative process
informed by the updated
risk assessment, local
priorities, and extensive
stakeholder engagement.

As part of this 2026
MJHMP update, the city
reviewed mitigation
actions from its prior
Local Hazard Mitigation
Plan to determine which
actions to carry forward,
which to consolidate, and
where entirely new
strategies were required.

This careful evaluation
ensured that the updated
action plan builds upon
past commitments while also responding to current risks and future challenges.

The plan addresses American Canyon’s most significant hazards, including wildfire, earthquake, flood, slope failure, drought, dam failure, and extreme weather. Each mitigation action is designed to align with FEMA’s hazard mitigation guidance and the requirements of the Disaster Mitigation Act of 2000. Where appropriate, overlapping or redundant actions were consolidated into broader, more comprehensive strategies that improve clarity, increase feasibility, and strengthen regional coordination.

The mitigation action prioritization method used by all participating jurisdictions is described in Volume 1, Section 4. Each action specific to American Canyon is documented in Table 1-17, which identifies the responsible department, implementation timeframe, potential funding sources, and resources required to complete the action. Each action is also assigned a unique alphanumeric identifier (see Figure 1-22) that links the strategy to its associated hazard and supports consistent monitoring and reporting.

American Canyon’s approach recognizes that some hazards are most effectively addressed through regional efforts. Flood protection, drought resilience, and wildfire risk reduction often extend beyond the city’s boundaries and require collaboration with county, regional, and state partners. By aligning local actions with regional strategies, American Canyon helps to consolidate resources, maximize funding Figure 1-22: Mitigation Action Number Key
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opportunities, and ensure that mitigation projects achieve the greatest benefit for San Pablo Bay, the Napa Valley, and the wider Napa County community.

Collectively, these mitigation actions provide a roadmap for reducing hazard risk, protecting vulnerable populations, and strengthening the long-term resilience of American Canyon.

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Table 1-17: City of American Canyon Mitigation Action Plan Mitigation No. Hazard
Type
SubHazardMitigation
Type
Year Primary
Agency
Title Description Responsible
Party
Estimated
Cost
Estimated
Benefit
Time
Frame
HMA
Activity
Type
Potential Grant
Source
Priority Related Problem Statements
ma-CC-AC-10 Climate
Change
Sea Level
Rise
PPRO -
Property
Protection ,
NRP - Natural
Resource
Protection , SP
- Structural
Projects
2020 City of
American
Canyon
Critical
Facilities SeaLevel Rise
Protections
Design and construct sea level rise adaptation
measures for critical facilities like the WWTP,
Public Works Yard, pump stations, and Wetlands
Edge Road, including measures such as
ecologically responsive shoreline hardening and
elevation.

Community
Infrastructure &
Development
Department
High High 3-5 Years Project HMGP / BRIC ,
FMA , General
Fund
High ps-CC-AC-16, ps-FL-AC-120,
ps-FL-AC-122, ps-FL-AC-123
ma-DF-AC-215 Dam
Failure
PE&A - Public
Education &
Awareness ,
ES -
Emergency
Services
2026 City of
American
Canyon
Dam
Inundation
Preparedness
Enhance public education and awareness of
dam inundation risk and preparedness through
outreach and signage for neighborhoods and in
inundation zones.

City Manager's
Office
Low Medium 3-5 Years Capacity /
Capability
Building

HMGP / BRIC ,
General Fund
Medium ps-DF-AC-32, ps-DF-AC-33
ma-DR-AC-20 Drought PRV -
Prevention ,
PE&A - Public
Education &
Awareness
2020 City of
American
Canyon
Drought
Preparedness
Program
Strengthen drought preparedness with
mandatory conservation triggers, recycled water
expansion, leak-detection programs, and
targeted assistance for seniors and renters.

Community
Infrastructure &
Development
Department
Low Medium 3-5 Years Project HMGP / BRIC ,
General Fund
High ps-DR-AC-42, ps-DR-AC-308,
ps-CC-AC-307
ma-EQ-AC-32 Earthquake PE&A - Public
Education &
Awareness
2013 City of
American
Canyon
Seismic
Safety
Outreach
Program
Conduct annual public outreach and enhance
public information on seismic safety by
promoting the Brace & Bolt program and through
workshops targeted for renter and mobile home
resident safety education.

Community
Infrastructure &
Development
Department
Low Medium Ongoing Capacity /
Capability
Building

HMGP / BRIC ,
General Fund
Medium ps-EQ-AC-69, ps-EQ-AC-70,
ps-EQ-AC-71
ma-EQ-AC-33 Earthquake PPRO -
Property
Protection , SP
- Structural
Projects
2020 City of
American
Canyon
Critical
Facilities
Seismic
Retrofits
Assess critical facilities and infrastructure and
retrofit high-priority assets to maintain
functionality after severe shaking.

Community
Infrastructure &
Development
Department
High High 5-10 Years Project HMGP / BRIC ,
General Fund
Medium ps-EQ-AC-79, ps-EQ-AC-80,
ps-EQ-AC-70
ma-EH-AC-216 Extreme
Heat
PPRO -
Property
Protection , ES
- Emergency
Services
2026 City of
American
Canyon
Enhance
Cooling
Centers
Network
Identify, assess, and improve facilities for use as
cooling centers and other shelters, such as the
Adult Activity Center, Mikolajcik Center, and
City Hall, including back-up power and ADA
upgrades.

City Manager's
Office
Medium Medium 3-5 Years Capacity /
Capability
Building

HMGP / BRIC ,
General Fund
Medium ps-EH-AC-310, ps-EH-AC-311,
ps-EH-AC-312, ps-EH-AC-313
ma-FL-AC-46 Flood PPRO -
Property
Protection ,
PE&A - Public
Education &
Awareness
2013 City of
American
Canyon
Flood
Mitigation
Support
Program
Assist property owners with flood mitigation for
flood-prone residential structures, especially
100-yr and 500-yr floodplain mobile home parks
and vulnerable neighborhoods.

Community
Infrastructure &
Development
Department
High High 5-10 Years Project HMGP / BRIC ,
FMA , General
Fund
Medium ps-FL-AC-122, ps-FL-AC-121,
ps-FL-AC-120
ma-FL-AC-47 Flood PE&A - Public
Education &
Awareness ,
ES -
Emergency
Services
2020 City of
American
Canyon
Flood
Notification
System
Improvement
Improve flood alerts by integrating early
warning systems like real-time stream and
culvert monitors and enhanced coordination
with NWS and other partners.

Community
Infrastructure &
Development
Department
Medium Medium 3-5 Years Project HMGP / BRIC ,
General Fund
High ps-DF-AC-32, ps-DF-AC-33,
ps-FL-AC-120, ps-FL-AC-120,
ps-FL-AC-123
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Mitigation No. Hazard
Type
SubHazardMitigation
Type
Year Primary
Agency
Title Description Responsible
Party
Estimated
Cost
Estimated
Benefit
Time
Frame
HMA
Activity
Type
Potential Grant
Source
Priority Related Problem Statements
ma-SW-AC-121 Severe
Weather
Heavy Rain PRV -
Prevention ,
NRP - Natural
Resource
Protection , SP
- Structural
Projects
2020 City of
American
Canyon
Stormwater
Drainage
Resilience
Program
Update the stormwater management plan and
repair, upsize, or replace known failing culverts
and drainage infrastructure contributing to
recurrent flooding along American Canyon
Creek and tidal areas, including through naturebased solutions where feasible.

Community
Infrastructure &
Development
Department
Medium High 3-5 Years Project HMGP / BRIC ,
FMA , General
Fund
High ps-SW-AC-143, ps-SW-AC-309
ma-SW-AC-214 Severe
Weather
NRP - Natural
Resource
Protection , ES
- Emergency
Services
2026 City of
American
Canyon
High Wind
Resilience
Program
Regularly assess and mitigate wind damageprone trees along major corridors and around critical facilities and install backup power to
ensure continuity of services.

Community
Infrastructure &
Development
Department
Medium High 3-5 Years Capacity /
Capability
Building

HMGP / BRIC ,
General Fund
Medium ps-SW-AC-143, ps-SW-AC-309
ma-SF-AC-217 Slope
Failure
NRP - Natural
Resource
Protection , SP
- Structural
Projects
2026 City of
American
Canyon
Slope Stability
Assessment &
Erosion
Control
Improvements
Identify and assess high-risk slopes and
incorporate any needed improvements into the
CIP for stabilization, stormwater management,
erosion control, or other mitigation measures.

Parks &
Recreation
Department
Medium High 3-5 Years Project HMGP / BRIC ,
General Fund
Low ps-SF-AC-314, ps-SF-AC-315,
ps-SF-AC-316
ma-WF-AC-86 Wildfire PPRO -
Property
Protection ,
NRP - Natural
Resource
Protection
2020 City of
American
Canyon
WUI
Protection
Program
Maintain and expand fuel breaks, improve
defensible space around structures, and conduct
structural hardening at critical facilities,
including Legacy High School, Water Treatment
Plant, and utility corridors.

Community
Infrastructure &
Development
Department
Medium High 1-3 Years Project HMGP / BRIC ,
General Fund ,
CalFIRE
High ps-WF-AC-173, ps-WF-AC-174,
ps-WF-AC-175, ps-WF-AC-185
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1.6.3 Status of Previous Mitigation Actions
In 2020, the City of American Canyon adopted its previous FEMA-approved HMP. This 2026 MJHMP represents a comprehensive update from that previous plan, as discussed in Volume 1, Section 1.5. Table 1-18 provides status updates for all of the previous mitigation actions in the City of American Canyon HMP, from which many of the mitigation actions in Table 1-17 were sourced and revised.

Table 1-18: City of American Canyon Status of Previous Mitigation Actions Mitigation
No.

Hazard
Type Status Year Primary Agency Title/Description Reason Completed/ Cancelled ma-CC-AC10
Climate
Change Ongoing 2020 City of American Canyon
Critical Facilities Sea-Level
Rise Protections Revised
ma-DR-AC20 Drought Ongoing 2020 City of American
Canyon
Drought Preparedness
Program Revised
ma-EQ-AC32 Earthquake Ongoing 2013 City of American
Canyon
Seismic Safety Outreach
Program Revised
ma-EQ-AC33 Earthquake Ongoing 2020 City of American
Canyon
Critical Facilities Seismic
Retrofits Revised
ma-FL-AC46 Flood Ongoing 2013 City of American
Canyon
Flood Mitigation Support
Program Revised
ma-FL-AC47 Flood Ongoing 2020 City of American
Canyon
Flood Notification System
Improvement Revised
ma-SW-AC121
Severe
Weather Ongoing 2020 City of American Canyon
Stormwater Drainage
Resilience Program Revised
ma-WF-AC86 Wildfire Ongoing 2020 City of American
Canyon WUI Protection Program Revised
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Section 2. City of Calistoga
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Napa County
2026 Multi-Jurisdictional Hazard Mitigation Plan Update City of Calistoga (CL)
Municipal Annex
Section 2. City of Calistoga.........................................................................................................2-7

2.1 Scope & Purpose .....................................................................................................................................................................2-7

2.2 Jurisdictional Setting...........................................................................................................................................................2-7

2.2.1 Geography & Climate ..................................................................................................................................................2-8

2.2.2 Demographics & Vulnerable Populations.........................................................................................................2-10

2.2.3 Economy........................................................................................................................................................................2-26

2.2.4 Growth Trends & Future Development..............................................................................................................2-26

2.3 Planning Process .................................................................................................................................................................2-27

2.3.1 Public Input & Draft Review ...................................................................................................................................2-29

2.4 What’s New.............................................................................................................................................................................2-30

2.4.1 Mitigation Activities .................................................................................................................................................2-30

2.4.2 Mitigation Successes................................................................................................................................................ 2-31

2.5 Risk Assessment.................................................................................................................................................................. 2-31

2.5.1 Hazard Screening & Prioritization ......................................................................................................................2-32

2.5.2 Vulnerability to Specific Hazards........................................................................................................................2-36

2.5.3 Climate Change Impacts & Vulnerable Populations....................................................................................2-53

2.5.4 Hazard Problem Statements..................................................................................................................................2-54

2.6 Mitigation Strategy .............................................................................................................................................................2-57

2.6.1 Capabilities & Opportunities..................................................................................................................................2-58

2.6.2 City of Calistoga Mitigation Action Plan .......................................................................................................... 2-71

2.6.3 Status of Previous Mitigation Actions...............................................................................................................2-75 CAL OES SUBMITTAL - JUNE 2026
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List of Figures
Figure 2-1: City of Calistoga Geographic Overview Map.....................................................................................................2-9 Figure 2-2: City of Calistoga Median Household Income Map.......................................................................................2-13 Figure 2-3: City of Calistoga Poverty Status Map ................................................................................................................2-14 Figure 2-4: City of Calistoga Housing Occupancy Map.....................................................................................................2-15 Figure 2-5: City of Calistoga Dependent Age Groups Map...............................................................................................2-19 Figure 2-6: City of Calistoga Disabled Elderly Map............................................................................................................ 2-20 Figure 2-7: City of Calistoga Race and Ethnicity Map...................................................................................................... 2-22 Figure 2-8: City of Calistoga Spanish-Speaking Households Map ...............................................................................2-23 Figure 2-9: City of Calistoga CDC Social Vulnerability Index Map...............................................................................2-25 Figure 2-10: City of Calistoga Risk Assessment Matrix ................................................................................................... 2-34 Figure 2-11: Exposure Summary – City of Calistoga Wildfire Risk.............................................................................. 2-38 Figure 2-12: Exposure Summary – City of Calistoga Earthquake Risk (M7.1 Hunting Creek–Berryessa)....2-41 Figure 2-13: Exposure Summary – City of Calistoga Earthquake Risk (M6.7 West Napa).................................. 2-42 Figure 2-14: City of Calistoga Liquefaction Risk ................................................................................................................. 2-43 Figure 2-15: City of Calistoga Flood Risk (FEMA Zones and DWR Awareness Zones)......................................... 2-46 Figure 2-16: Exposure Summary – City of Calistoga Flood Risk (FEMA Zones) .................................................... 2-47 Figure 2-16: Drought Severity Timeline 2000-2024............................................................................................................ 2-50 Figure 2-17: Mitigation Action Number Key ..........................................................................................................................2-71 List of Tables
Table 2-1: City of Calistoga Population and Households ..................................................................................................2-10 Table 2-2: City of Calistoga Income and Poverty..................................................................................................................2-11 Table 2-3: City of Calistoga Renter- and Owner-Occupied Housing............................................................................2-12 Table 2-4: City of Calistoga Households with Seniors.......................................................................................................2-16 Table 2-5: City of Calistoga Households with Children.....................................................................................................2-17 Table 2-6: City of Calistoga Population with Disabilities and Access to Transportation....................................2-18 Table 2-7: City of Calistoga Household Languages.............................................................................................................2-21 Table 2-8: City of Calistoga Planning Team and Steering Group Members............................................................. 2-28 Table 2-9: City of Calistoga Planning Team Meetings...................................................................................................... 2-29 Table 2-10: City of Calistoga Document Review of Potential Hazards ........................................................................2-33 Table 2-11: City of Calistoga Hazards Prioritization Summary ......................................................................................2-35 Table 2-12: City of Calistoga National Flood Insurance Program Information....................................................... 2-45 Table 2-13: Drought Classifications and Impacts................................................................................................................ 2-49 Table 2-14: City of Calistoga Hazard Problem Statements.............................................................................................. 2-54 Table 2-15: City of Calistoga Capabilities and Opportunities Assessment............................................................... 2-66 Table 2-16: City of Calistoga Mitigation Action Plan..........................................................................................................2-73 Table 2-17: City of Calistoga Status of Previous Mitigation Actions ............................................................................2-75 CAL OES SUBMITTAL - JUNE 2026
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Adoption Resolution
To comply with the Federal Disaster Mitigation Act of 2000 (DMA 2000), the Calistoga City Council has officially adopted this 2026 Napa County Multi-Jurisdictional Hazard Mitigation Plan, including Volume 1 in its entirety as well as this Volume 2 municipal annex. The adoption of the MJHMP recognizes the city’s commitment to reducing the impacts of natural hazards within its jurisdiction and across Napa County.

A copy of the city’s adoption record is provided on the following pages. Adoption records for all jurisdictions are summarized in Volume 1, Table ES-1.

ADOPTION RECORD TO BE INSERTED UPON COMPLETION.

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Section 2.City of Calistoga

2.1 Scope & Purpose
This Jurisdictional Annex for the City of Calistoga of the 2026 Napa County Multi-Jurisdictional Hazard Mitigation Plan (MJHMP) details the hazard mitigation planning elements specific to the city’s planning area. The annex is not intended to be a standalone document but appends to and supplements the information contained in the umbrella plan document (Volume 1). As such, all sections of the umbrella plan, including the planning process and other procedural requirements, apply to and were met by the City of Calistoga. This annex provides additional information specific to the city, with a focus on hazard identification and risk assessment, vulnerability assessment, problem statements, mitigation strategy, and capabilities assessment. Below are the City of Calistoga Points of Contact:

Primary Point of Contact Alternate Point of Contact
Jed Matcham, Fire Chief
City of Calistoga
1232 Washington Street
Calistoga, CA 94515
Telephone: (707) 942-2822
email: [email protected]
Mitchell Celaya, Acting City Manager
City of Calistoga
1232 Washington Street
Calistoga, CA 94515
Telephone: (707) 942-2813
email: mcelaya@ calistogaca.gov

2.2 Jurisdictional Setting
The City of Calistoga is located in the north-western Napa Valley in Napa County in Northern California, approximately 55 miles north of San Francisco. The city is bounded by the Mayacamas Mountains to the west, the Napa Valley to the south, Mount St. Helena to the north, and the Howell Mountains to the east. The city is situated along Highways 29 and 128, which provide regional access to other parts of Napa County, as well as Sonoma and Lake Counties. Calistoga is a small town characterized by a mix of residential neighborhoods, a Central Business District, resorts and other visitor-serving commercial business, and wine production facilities. The Old Faithful Geyser of California is a local Calistoga landmark.

Calistoga encompasses approximately 2.5 square miles and is located on the Napa River. This varied topography and proximity to a major waterway influences the city’s exposure to natural hazards, including flooding, seismic shaking, wildfire along the wildland-urban interface, and climate change-related impacts such as extreme heat and increased flood risk.

The city operates as a general law city under a council-manager form of government and provides a full range of municipal services, including fire protection, police protection, public works, community development, and water, wastewater, and recycled water services.

In addition to its incorporated boundaries, the city provides water and wastewater services to areas outside the city limits. Under California planning law, these extraterritorial service areas are considered part of the CAL OES SUBMITTAL - JUNE 2026
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city’s planning area because damage to infrastructure beyond municipal boundaries can directly affect public health, safety, and continuity of essential services within Calistoga. The City of Calistoga’s location within Napa County is shown in Figure 2-1.
▪ Year of Incorporation: 1886
▪ 2021 Population: 5,191 (US Census Bureau, 2021)
▪ Population Growth: Slow population growth from founding until 1970s; moderate population growth since.

2.2.1 Geography & Climate
The City of Calistoga is located in the north-western Napa Valley at the base of the Mayacamas Mountains.

The city is bisected by the Napa River. Mount St. Helena, the highest point in Napa County, is located north of Calistoga, and serves as the headwaters of the Napa River. Figure 2-1 provides a geographic overview of Napa County.

Hydrologically, Calistoga is part of the Napa River watershed, which conveys runoff from northern Napa County through the City before discharging into San Pablo Bay. Portions of the city lie near or within historic floodplain areas, particularly adjacent to the Napa River. These low-lying areas are subject to flooding.

Stormwater systems throughout the city are designed to manage runoff generated by seasonal precipitation.

The climate in Calistoga and the Napa Valley is warmer than that in the rest of the Bay Area. Nevertheless, in summer, Calistoga and the rest of the Napa Valley are protected from the hot weather of the Central Valley of California by the coastal mountain ranges. The Pacific Ocean provides a source of cool, moist air in the summer, and this steady flow of marine air holds temperatures at a moderate level. The greatest variation in temperature occurs in summer. In Calistoga, average high summer temperatures are in the upper 80's to the mid 90's. Winters are generally mild, but there are occasional cold spells. Average high winter temperatures are in the high 50's to low 60's, while the minimum temperatures are in the upper 20's and 30's. Frost is common during clear, calm mornings in the late fall and winter.

The growing season, which is the period between the last freezing temperature event in spring and the first in fall, ranges from 215 to 260 days in Calistoga. Most of the annual precipitation falls during the period of November through April. The greatest amount of rainfall is expected to range from 0.9 inch in one hour once in two years to 2.1 inches in one hour once in 100 years.

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Figure 2-1: City of Calistoga Geographic Overview Map
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2.2.2 Demographics & Vulnerable Populations
This section describes the demographic characteristics of the City of Calistoga to guide hazard mitigation planning efforts. Natural disasters affect communities both physically and socially, with demographic composition playing a central role in determining how impacts are distributed, particularly among vulnerable groups facing greater challenges in preparedness, response, and recovery. Understanding the area's social and economic landscape also helps assess potential social costs from infrastructure damage, including housing, industry, public facilities, essential services, and transportation.

Exploring local demographic data may help to identify groups and geographic areas with specific vulnerability to hazard events. In the context of all-hazards preparedness and response planning, at-risk individuals (often used interchangeably with “vulnerable populations”) are defined federally as “children, pregnant women, senior citizens, and other individuals who have access or functional needs in the event of a public health emergency.” (42 U.S.C. § 2802(b)(4)(B) (2019)) These populations may include, but are not limited to, individuals who are economically disadvantaged, living with disabilities, dependent on caregivers, from historically marginalized communities, have limited English proficiency or are nonEnglish speaking, lack access to transportation, are experiencing homelessness, or have chronic medical conditions.

Certain populations face greater risk following a natural hazard event due to age, economic mobility, physical disability, geographic location, or a combination of factors. Vulnerability in the face of a hazard event is not a fixed characteristic; the same individual may be at risk for some hazards but not at risk for others. Planning for vulnerable populations in the context of hazard mitigation can help communities to prioritize limited resources where they will be the most effective. Refer to Volume 1, Section 1.4.3, for a more in-depth discussion of planning for vulnerable populations, at-risk individuals with access and functional needs, and environmental justice.

The City of Calistoga is also designated as an Equity Priority Community by the Metro Transportation Commission based on specific ACS data that helps indicate community vulnerability such as communities of low income, historically marginalized racial groups, or English proficiency, With this designation, the MTC prioritizes these communities in funding for programs aimed at increasing mobility, affordability and sustainability. Acknowledging this funding source for Calistoga is important when considering future planning projects.

The total population, total number of households, and average household size of the City of Calistoga are presented in Table 2-1, compared to the other municipalities and Napa County. As shown in the table, Calistoga is the second-smallest city in Napa County.

Table 2-1: City of Calistoga Population and Households
Area Total Population Total Households (HH) Average HH Size Napa County 137,384 55,588 2.40
City of Napa 79,233 31,666 2.47
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City of American Canyon 21,669 5,924 3.64
City of Calistoga 5,191 2,330 2.20
City of St. Helena 5,426 2,963 1.81
Town of Yountville 3,397 1,824 1.45
Source: ACS 5-Year, 2017-2022
Income & Housing
Economic mobility is one of the most important predictors of natural hazard vulnerability. Low-income residents are more likely to occupy housing which is inadequately maintained or otherwise poorly built to withstand extreme events. For example, mobile or modular homes are more susceptible to damage in earthquakes and floods than other types of residences and are less likely to contain air conditioning units to cope with high heat events. In urban areas, low-income residents are more likely to occupy older homes and apartment complexes with unreinforced masonry, which is particularly susceptible to seismic damage.

Low-income households and communities face disproportionate financial burden from costs associated with disaster preparedness, response, and recovery. Disasters create unexpected expenses which may serve as “tipping points” for families and individuals living on the edge of poverty or homelessness. Recovery costs may be higher for those without resources to conduct hazard mitigation activities ahead of time. Families and individuals who lack access to transportation may be unable to evacuate ahead of an emergency. (Krause & Reeves, 2017)
Low-income residents and renters are also less likely to purchase insurance, meaning that those with the most to lose during an event are also the least prepared to deal with potential losses. Major hurricane events in recent history such as Harvey, Irma, and Katrina all demonstrate that low-income or historically marginalized communities face increased vulnerability to hazard events and struggle the most to recover.

Median household income in the City of Calistoga is just under $97,000, with an overall poverty rate of around 5%. By comparison, median income and poverty rates for Napa County were nearly $106,000 and 8%, respectively; refer to Table 2-2. Median income and poverty rates are also shown on the block group level in Figure 2-2 and Figure 2-3.

Table 2-2: City of Calistoga Income and Poverty
Area Median Income Poverty Rate
Napa County $105,809 7.9%
City of Napa $100,273 8.1%
City of American Canyon $122,694 7.4%
City of Calistoga $96,667 5.4%
City of St. Helena $135,781 5.7%
Town of Yountville $75,134 10.6%
Source: ACS 5-Year, 2017-2022
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Renters are also more vulnerable to natural hazards, as they are less likely to take out property insurance and the decision to make major structural improvements typically lies with the property owner. Federal disaster recovery services can exacerbate inequality between renters and homeowners; payout amounts are significantly higher for homeowners applying through FEMA’s Individual Assistance (IA) program; from 1999 to 2013 U.S. homeowners saw their wealth increase with local hazard damages, whereas renters’ wealth decreased. (Howell, Junia; Elliot, James, 2019)
Approximately 40% of occupied housing units in the City of Calistoga are renters, compared to approximately 35% for Napa County as a whole; refer to Table 2-3.

Table 2-3: City of Calistoga Renter- and Owner-Occupied Housing Jurisdiction # Occupied
Housing Units
# Renter
Occupied % Renter Occupied # Owner Occupied
% Owner
Occupied
Napa County 49,738 17,676 35.5% 32,062 64.5%
City of Napa 26,978 10,616 39.4% 16,362 60.6%
City of American Canyon 6,192 1,371 22.1% 4,821 77.9%
City of Calistoga 2,042 822 40.3% 1,220 59.7%
City of St. Helena 2,380 1,048 44% 1,332 56.0%
Town of Yountville 1,050 362 34.5% 688 65.5%
Source: ACS 5-Year, 2017-2022
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Figure 2-2: City of Calistoga Median Household Income Map CAL OES SUBMITTAL - JUNE 2026
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Figure 2-3: City of Calistoga Poverty Status Map
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Figure 2-4: City of Calistoga Housing Occupancy Map
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Dependent & Disabled Populations
Age is a significant factor in assessing vulnerability to natural hazards. Both older adults and children are considered dependent populations due to their reliance on caregivers for safety, mobility, and support during emergency events. These populations face heightened risks during disasters such as floods, wildfires, and earthquakes, particularly when compounding factors such as poverty, disability, or social isolation are present.

In the City of Calistoga, approximately 43% of households include at least one individual over the age of 65, and over 18% of all households consist of seniors living alone. While only around 4% of senior households live below the poverty line (Table 2-4), seniors, particularly those who are low-income or socially isolated, remain among the most vulnerable populations in disaster situations. Challenges for older adults may include limited mobility, chronic health conditions, reduced digital literacy, and lack of access to real-time emergency alerts. Seniors living alone may require additional assistance during evacuations or power outages, and assisted living facilities necessitate advanced coordination to ensure continuity of care and safety during emergencies.

Children represent another dependent population requiring special consideration (Table 2-5). In Calistoga, nearly 20% of households include individuals under the age of 18, with around 1% of these households headed by a single caregiver. During emergencies, children are entirely dependent on caregivers for decision-making, transportation, and access to essential resources. Disruptions to schools, childcare, and youth services can result in significant emotional, educational, and developmental impacts. Families with limited means or single caregivers may also face greater challenges in securing housing, supplies, and recovery assistance.

Figure 2-5 highlights areas within Calistoga with higher concentrations of economically dependent age groups, informing targeted outreach and response strategies during emergencies.

Table 2-4: City of Calistoga Households with Seniors
Jurisdiction Households (HH) 65+ % 65+ Alone %
65+
Poverty %
Napa County 55,588 18,777 33.8% 4,816 8.7% 1,271 2.3%
City of American Canyon 5,924 1,772 29.9% 184 3.1% 111 1.9% City of Calistoga 2,330 1,003 43.0% 419 18.0% 101 4.3%
City of Napa 31,666 10,299 32.5% 2,674 8.4% 703 2.2%
City of St. Helena 2,963 1,153 38.9% 296 10.0% 42 1.4%
Town of Yountville 1,824 873 47.9% 351 19.2% 77 4.2%
Source: ACS 5-Year, 2017-2022
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Table 2-5: City of Calistoga Households with Children
Jurisdiction Households <18 %
<18 Single
Caregiver %
Napa County 55,588 14,596 26.3% 3,109 5.6%
City of American Canyon 5,924 2,633 44.4% 417 7.0%
City of Calistoga 2,330 471 20.2% 33 1.4%
City of Napa 31,666 8,934 28.2% 2,315 7.3%
City of St. Helena 2,963 619 20.9% 168 5.7%
Town of Yountville 1,824 160 8.8% 0 0.0%
Source: ACS 5-Year, 2017-2022
Elderly populations face increased risks during disaster events due to age-related health conditions, mobility limitations, and potential social isolation. In Calistoga, approximately 11% of the noninstitutionalized population lives with a disability, a slightly lower rate than the countywide average of 12% (Table 2-6).

Among those with access and functional needs, elderly individuals with disabilities represent a highly vulnerable subpopulation when it comes to disaster preparedness, response, and recovery. This group includes seniors living with physical or cognitive impairments such as hearing or vision loss, reduced mobility, reliance on assistive medical devices, neurodivergence, or chronic health conditions that may be exacerbated by hazard events (e.g., exposure to wildfire smoke or extreme heat).

Figure 2-6 illustrates that in some portions of the city, more than 47% of the elderly population is estimated to have one or more disabilities, while other areas show lower proportions or lack available data. The spatial distribution shown on this map suggests that vulnerability is not uniform across the city and that certain neighborhoods may have greater needs for evacuation assistance, medical support, and continuity of care during emergencies. Seniors with disabilities may also be more sensitive to extended power outages, disruptions to medical services, and transportation interruptions. These risks are expected to increase under climate change conditions that intensify extreme heat events and strain emergency response resources.

The combination of advanced age and disability can present significant challenges not only during emergency response but also in implementing hazard mitigation measures. Elderly individuals with disabilities may face physical, financial, or logistical barriers to undertaking activities such as seismic retrofitting, anchoring fuel tanks, installing foundation bracing, or implementing residential flood-proofing techniques. Many live in older housing stock that is more vulnerable to earthquake damage or repetitive flooding and may lack the resources or support networks needed to complete mitigation upgrades.

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Table 2-6: City of Calistoga Population with Disabilities and Access to Transportation Jurisdiction Population
Persons w/
Disability %
Persons
Reliant on
Public
Trans. % Households
HH w/o
Vehicle %
Napa County 137,384 16,544 12.0% 890 0.6% 55,588 2,421 4.4% City of American
Canyon 21,669 2,201 10.2% 287 1.3% 5,924 138 2.3%
City of Calistoga 5,191 573 11.0% 36 0.7% 2,330 83 3.6% City of Napa 79,233 9,837 12.4% 291 0.4% 31,666 1,554 4.9% City of St. Helena 5,426 683 12.6% 121 2.2% 2,963 219 7.4% Town of
Yountville 3,397 683 20.1% 15 0.4% 1,824 210 11.5%
Source: ACS 5-Year, 2017-2022
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