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Natural hazard risk in Sonoma County, California

Updated October 30, 2026. Based on FEMA, NOAA and OpenFEMA data. Published by Humblebee.

FEMA overall Risk Index rating: Relatively High (score 99.0 of 100)[5]

Expected annual loss (FEMA)
$604.7 million[1]
Federal disaster declarations since 1964
33[2]
NFIP flood claims paid, 1978 to 2026
$132.1 million[3]
Tornadoes recorded, 1950 to 2024
13[4]

FEMA's National Risk Index rates the overall natural hazard risk for Sonoma County as Relatively High, with a score of 99.0 out of 100[5]. The hazards with the highest FEMA scores here are landslide, earthquake and drought[6].

FEMA risk ratings for each hazard

Ratings and expected losses from the FEMA National Risk Index. Each rating compares this county with all US counties for that hazard, from Very Low to Very High. They are planning estimates, not predictions, and they do not describe any single property.

FEMA's National Risk Index estimates Expected Annual Loss from all 18 natural hazards in Sonoma County at $604.7 million a year[1]. That is a FEMA estimate of average yearly loss, not money anyone paid. By FEMA's sorted values, the largest parts come from earthquake ($283.6 million a year), inland flooding ($279.8 million a year) and wildfire ($16.8 million a year)[7]. FEMA rates social vulnerability as Relatively Low, with a score of 29.7[8]. FEMA rates community resilience as Relatively High, with a score of 66.2[9]. All ratings compare Sonoma County with other US counties, and FEMA says the index does not predict next year's losses[10].

Hazards sorted by FEMA hazard-type Risk Index score, highest first
HazardFEMA risk ratingExpected annual loss
LandslideRelatively High$5.0 million[11]
EarthquakeRelatively High$283.6 million[12]
DroughtRelatively High$14.4 million[13]
Inland FloodingRelatively High$279.8 million[14]
WildfireRelatively High$16.8 million[15]
Heat WaveRelatively Moderate$3.0 million[16]
Volcanic ActivityRelatively Low$2,854[17]
Coastal FloodingRelatively Moderate$1.1 million[18]
LightningRelatively Moderate$341,000[19]
TsunamiVery Low$244,000[20]
HailVery Low$60,000[21]
TornadoVery Low$163,000[22]
Strong WindVery Low$119,000[23]
AvalancheVery Low$10[24]
Winter WeatherVery Low$6,414[25]

Rated Not Applicable by FEMA for this county: hurricane, ice storm[26].

Social vulnerability and community resilience

FEMA uses these two ratings to scale expected losses into the Risk Index.

FEMA measureRatingScore
Social vulnerabilityRelatively Low29.7[8]
Community resilienceRelatively High66.2[9]

Flooding and flood insurance

FEMA rates inland flooding Relatively High in Sonoma County, with a score of 99.1 out of 100[14]. OpenFEMA data as of 2026-08-03 show 3,971 residential structures inside FEMA's mapped Special Flood Hazard Area, and 31.3% of homes inside the SFHA are insured through the NFIP[27]. Across the whole county, the NFIP penetration rate is 1.1%[27]. OpenFEMA's NFIP claims data list 7,403 claims for losses from 1978 to 2026, and NFIP paid $132.1 million in total[3]. For a specific address, use FEMA's Flood Map Service Center[28].

Measure Value
Inland Flooding, FEMA risk rating[14] Relatively High, $279.8 million expected loss a year
Coastal Flooding, FEMA risk rating[18] Relatively Moderate, $1.1 million expected loss a year
NFIP residential flood policies in force (2026)[27] 1,790 of 167,061 homes
Homes in FEMA's mapped high-risk flood area (SFHA)[27] 3,971, of which 1,244 insured
NFIP flood claims, 1978 to 2026[3] 7,403 filed, $132.1 million paid

Is a specific address in a flood zone? Only FEMA's flood maps answer that, property by property[28]. This page describes the whole county.

Search an address on the FEMA Flood Map Service Center

Disaster declarations and tornado records

OpenFEMA lists 33 federal disaster declarations for natural hazards that include Sonoma County since 1964[2]. By incident type, fire accounts for 11, severe storm for 9 and flood for 9[2]. The most recent listed is DR-4699-CA, declared 2023-04-03[29]. NOAA's tornado database records 13 tornadoes touching the county from 1950 to 2024, and the most recent was on 2011-03-18[4].

Federal disaster declarations for natural hazards that include Sonoma County, since 1964
Incident type Declarations
Fire[2] 11
Severe Storm[2] 9
Flood[2] 9
Drought[2] 1
Hurricane[2] 1
Coastal Storm[2] 1
Freezing[2] 1
Most recent declarations
Declaration Incident Declared
DR-4699-CA[29] Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, And Mudslides 2023-04-03
EM-3592-CA[29] Severe Winter Storms, Flooding, Landslides, And Mudslides 2023-03-10
DR-4683-CA[29] Severe Winter Storms, Flooding, Landslides, And Mudslides 2023-01-14
EM-3591-CA[29] Severe Winter Storms, Flooding, And Mudslides 2023-01-09
DR-4569-CA[29] Wildfires 2020-10-16

How to prepare

Steps from Ready.gov, FEMA's preparedness site, for the hazards with the highest FEMA ratings here. Follow instructions from local officials and the National Weather Service when a warning is issued.

Earthquakes

Before

  • Practice Drop, Cover, and Hold On with your family and coworkers.
  • Sign up for earthquake alerts that can warn you before shaking starts.
  • Make a plan with an out-of-state contact and a place to meet if you get separated.
  • Anchor heavy items such as bookcases, refrigerators and water heaters, and keep heavy things on low shelves.
  • Consider earthquake insurance. Standard homeowners policies do not cover earthquake damage.

During

  • Drop to your hands and knees, cover your head and neck, and hold on until the shaking stops.
  • Indoors, stay where you are and avoid doorways. Outdoors, move to an open area away from buildings and power lines.
  • If you are driving, pull over, stop and set the parking brake.

Source: Ready.gov, earthquakes

Floods

Before

  • Check your flood risk with FEMA's Flood Map Service Center, and remember that floods do not follow map lines.
  • Sign up for your community's warning system. NOAA Weather Radio also broadcasts alerts.
  • Buy flood insurance through the NFIP well before a disaster. Homeowners policies do not cover flooding, and a new policy typically takes up to 30 days to go into effect.
  • Make a household plan with evacuation routes, shelter locations and what to do in a flash flood.
  • Keep important documents in a waterproof container and make password-protected digital copies.

During

  • If you are told to evacuate, leave right away and never drive around barricades.
  • Do not walk, swim or drive through floodwater. Six inches of moving water can knock you down.
  • If you are trapped in a building, go to the highest level, but do not climb into a closed attic.

Source: Ready.gov, floods

Wildfires

Before

  • Sign up for community alerts and watch for air quality alerts.
  • Make sure everyone knows the evacuation plan, including for school, work and other places you go often.
  • Keep a fire-resistant zone of at least 30 feet around your home, clear of leaves and debris.
  • Use fire-resistant building materials and keep a hose long enough to reach every part of your property.
  • Pick a room you can seal off from outside air and keep a portable air cleaner ready.

During

  • Leave right away when authorities tell you to evacuate.
  • If you are trapped, call 9-1-1 with your location and turn on lights to help rescuers find you.
  • If you are not ordered to leave but there is smoke, stay in a safe indoor place or go to a community building with less smoke.

Source: Ready.gov, wildfires

Questions people ask

Is Sonoma County at risk of flooding?
FEMA rates inland flooding Relatively High for Sonoma County, compared with other US counties[14]. OpenFEMA lists 7,403 NFIP flood claims for losses from 1978 to 2026[3].
Is Sonoma County at risk of earthquakes?
FEMA rates earthquake risk Relatively High for Sonoma County, with an Expected Annual Loss of $283.6 million a year[12].
Does Sonoma County get tornadoes?
NOAA's tornado database records 13 tornadoes touching Sonoma County from 1950 to 2024[4]. FEMA rates tornado risk Very Low compared with other US counties[22].
How many disasters have been declared in Sonoma County?
OpenFEMA lists 33 federal disaster declarations for natural hazards that include Sonoma County since 1964[2].
How do I check a flood zone in Sonoma County?
Flood zones apply to specific properties, so look up an address in FEMA's Flood Map Service Center or ask the local floodplain manager[28].

Facts and sources

  1. FEMA National Risk Index (version 1.20, December 2025): Expected Annual Loss from all 18 natural hazards in Sonoma County is $604.7 million a year (Expected Annual Loss rating Relatively High, score 99.2). Of this, buildings account for $503.8 million, injuries and deaths (converted to dollars by FEMA) for $85.0... FEMA National Risk Index
  2. OpenFEMA Disaster Declarations Summaries list 33 federal disaster declarations for natural hazards that include Sonoma County since 1964 (21 major disaster, 12 emergency or fire management). By incident type: fire 11, severe storm 9, flood 9, drought 1, hurricane 1, coastal storm 1, freezing 1. Biological (such as... OpenFEMA Disaster Declarations
  3. HazardFacts tally of OpenFEMA NFIP Redacted Claims (losses from 1978 to 2026): 7,403 National Flood Insurance Program claims were filed for losses in Sonoma County, 6,240 of them with a payment, and NFIP paid $132.1 million in total (building, contents and increased cost of compliance, in dollars of the year paid).... OpenFEMA NFIP claims
  4. NOAA Storm Prediction Center tornado database (1950 to 2024): 13 recorded tornadoes touched Sonoma County. The strongest were rated F2 (most recent of them on 1958-06-01). 0 were rated F3/EF3 or stronger. The most recent recorded tornado was on 2011-03-18. Ratings used the Fujita scale until early 2007 and the... NOAA Storm Prediction Center
  5. FEMA National Risk Index (version 1.20, December 2025): the overall natural hazard Risk Index rating for Sonoma County is Relatively High, with a Risk Index score of 99.0 out of 100. The score is the county's percentile rank among all US counties. FEMA National Risk Index
  6. Among the 18 hazards in the FEMA National Risk Index (version 1.20, December 2025), the hazards with the highest hazard-type Risk Index scores for Sonoma County are landslide (99.8, Relatively High), earthquake (99.4, Relatively High), drought (99.3, Relatively High). HazardFacts sorted FEMA's published scores;... FEMA National Risk Index
  7. HazardFacts sorted FEMA's hazard-type Expected Annual Loss values for Sonoma County (National Risk Index v1.20): the largest are earthquake ($283.6 million a year), inland flooding ($279.8 million a year), wildfire ($16.8 million a year), out of $604.7 million a year from all 18 hazards. FEMA National Risk Index
  8. FEMA National Risk Index (version 1.20, December 2025): Social Vulnerability rating for Sonoma County is Relatively Low (score 29.7). FEMA describes social vulnerability as how susceptible social groups are to the harm natural hazards cause. FEMA National Risk Index
  9. FEMA National Risk Index (version 1.20, December 2025): Community Resilience rating for Sonoma County is Relatively High (score 66.2). FEMA describes community resilience as a community's ability to prepare for, withstand and recover from hazards. FEMA National Risk Index
  10. FEMA's National Risk Index FAQ (December 2025): Expected Annual Loss is FEMA's estimate of the average economic loss in dollars from natural hazards each year. The index is not meant to predict how much damage a community will have in the next year, and a hazard can still cause damage where a rating is low. Scores... FEMA National Risk Index documentation
  11. FEMA National Risk Index (version 1.20, December 2025), landslide in Sonoma County: Risk Index rating Relatively High (score 99.8 of 100). Expected Annual Loss $5.0 million a year (rating Relatively High). FEMA National Risk Index
  12. FEMA National Risk Index (version 1.20, December 2025), earthquake in Sonoma County: Risk Index rating Relatively High (score 99.4 of 100). Expected Annual Loss $283.6 million a year (rating Relatively High). FEMA's modeled annual frequency is 0.1172 events per year. FEMA National Risk Index
  13. FEMA National Risk Index (version 1.20, December 2025), drought in Sonoma County: Risk Index rating Relatively High (score 99.3 of 100). Expected Annual Loss $14.4 million a year (rating Relatively High). Annualized frequency 33.5 event-days per year, from recorded occurrences over a period of record of 22 years. FEMA National Risk Index
  14. FEMA National Risk Index (version 1.20, December 2025), inland flooding in Sonoma County: Risk Index rating Relatively High (score 99.1 of 100). Expected Annual Loss $279.8 million a year (rating Relatively High). Annualized frequency 2.54 event-days per year, from recorded occurrences over a period of record of 26... FEMA National Risk Index
  15. FEMA National Risk Index (version 1.20, December 2025), wildfire in Sonoma County: Risk Index rating Relatively High (score 98.2 of 100). Expected Annual Loss $16.8 million a year (rating Relatively High). FEMA's modeled annual frequency is 0.0039 events per year. FEMA National Risk Index
  16. FEMA National Risk Index (version 1.20, December 2025), heat wave in Sonoma County: Risk Index rating Relatively Moderate (score 88.8 of 100). Expected Annual Loss $3.0 million a year (rating Relatively Moderate). Annualized frequency 7 event-days per year, from recorded occurrences over a period of record of 18... FEMA National Risk Index
  17. FEMA National Risk Index (version 1.20, December 2025), volcanic activity in Sonoma County: Risk Index rating Relatively Low (score 85.0 of 100). Expected Annual Loss $2,854 a year (rating Relatively Low). FEMA National Risk Index
  18. FEMA National Risk Index (version 1.20, December 2025), coastal flooding in Sonoma County: Risk Index rating Relatively Moderate (score 68.6 of 100). Expected Annual Loss $1.1 million a year (rating Relatively Moderate). FEMA's modeled annual frequency is 3.4233 events per year. FEMA National Risk Index
  19. FEMA National Risk Index (version 1.20, December 2025), lightning in Sonoma County: Risk Index rating Relatively Moderate (score 58.6 of 100). Expected Annual Loss $341,000 a year (rating Relatively Moderate). Annualized frequency 3.73 events per year, from recorded occurrences over a period of record of 24 years. FEMA National Risk Index
  20. FEMA National Risk Index (version 1.20, December 2025), tsunami in Sonoma County: Risk Index rating Very Low (score 26.1 of 100). Expected Annual Loss $244,000 a year (rating Very Low). FEMA National Risk Index
  21. FEMA National Risk Index (version 1.20, December 2025), hail in Sonoma County: Risk Index rating Very Low (score 16.0 of 100). Expected Annual Loss $60,000 a year (rating Very Low). Annualized frequency 0.02 events per year, from recorded occurrences over a period of record of 37 years. FEMA National Risk Index
  22. FEMA National Risk Index (version 1.20, December 2025), tornado in Sonoma County: Risk Index rating Very Low (score 15.3 of 100). Expected Annual Loss $163,000 a year (rating Very Low). Annualized frequency 0.08 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  23. FEMA National Risk Index (version 1.20, December 2025), strong wind in Sonoma County: Risk Index rating Very Low (score 13.5 of 100). Expected Annual Loss $119,000 a year (rating Relatively Low). Annualized frequency 0.02 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  24. FEMA National Risk Index (version 1.20, December 2025), avalanche in Sonoma County: Risk Index rating Very Low (score 10.8 of 100). Expected Annual Loss $10 a year (rating Very Low). Annualized frequency 0.01 events per year, from recorded occurrences over a period of record of 28 years. FEMA National Risk Index
  25. FEMA National Risk Index (version 1.20, December 2025), winter weather in Sonoma County: Risk Index rating Very Low (score 8.0 of 100). Expected Annual Loss $6,414 a year (rating Very Low). Annualized frequency 0.74 events per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  26. FEMA National Risk Index (version 1.20, December 2025) rates these hazards Not Applicable for Sonoma County: hurricane, ice storm. FEMA uses Not Applicable when its source data has no historical record of the hazard in the community and the hazard is not considered geographically possible there. FEMA National Risk Index documentation
  27. NFIP Residential Penetration Rates (OpenFEMA, as of 2026-08-03): 1,790 residential flood insurance contracts were in force in Sonoma County, out of 167,061 residential structures, a penetration rate of 1.1%. Inside FEMA's mapped Special Flood Hazard Area there were 3,971 residential structures and 1,244 contracts,... OpenFEMA NFIP penetration rates
  28. FEMA's Flood Map Service Center is the official public source for flood maps (Flood Insurance Rate Maps) produced under the National Flood Insurance Program. Flood zones apply to specific properties: look up an address there or ask the local floodplain manager. County-level ratings do not tell you the flood zone of... FEMA Flood Map Service Center
  29. Most recent federal disaster declarations for natural hazards (table on this page). OpenFEMA Disaster Declarations

FEMA's National Risk Index compares each county with all other US counties. Ratings are relative (Very Low to Very High), not a measure of safety. Never call a place safe, unsafe, good or bad to live in. Risk Index and Expected Annual Loss values are FEMA estimates for planning. They do not predict next year's losses and do not apply to a single property. Flood zones are set by FEMA flood maps for specific properties. County ratings and flood insurance counts do not tell anyone whether an address is in a flood zone. Disaster declaration, NFIP and tornado counts are records of the past for this county only. Do not compare with other counties unless a fact does.

Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties, v1.20 (December 2025). Retrieved from fema.maps.arcgis.com on October 30, 2026. This product uses the Federal Emergency Management Agency's National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s). This product uses the FEMA OpenFEMA API, but is not endorsed by FEMA.