riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Sonoma County Disaster Risk

Sonoma County, California

FEMA Risk Rating

Relatively High

National Percentile

99th

of 3,144 counties

State Rank

#13

of 58 (1 = highest risk)

Flood Risk

99th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively High

Higher than 99% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively High

Higher than 98% of US counties

Tornado

Tornado and severe thunderstorm risk

Very Low

Higher than 15% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively High

Higher than 99% of US counties

Risk Overview

About Natural Disaster Risk in Sonoma County, California

Sonoma ranks in nation's highest-risk tier

Sonoma County's composite risk score of 99.08 places it well above the national average, earning a Relatively High rating. This score reflects exposure to multiple severe hazards that demand serious preparedness planning.

Among California's most at-risk counties

With a score of 99.08, Sonoma ranks among the top tier of California's 58 counties—significantly above the state average of 88.72. The county faces compounded risks from earthquakes, floods, and wildfires simultaneously.

Riskier than most North Bay neighbors

Sonoma's 99.08 score exceeds nearby Napa and Marin counties, positioning it as the highest-risk county in the immediate region. Only Ventura County statewide matches Sonoma's extreme composite risk profile.

Earthquakes and floods top your hazard list

Sonoma faces earthquake risk at 99.46 and flood risk at 99.17—both among California's highest. Wildfire risk at 98.22 adds a third major threat, particularly in the county's northern and eastern communities.

Get triple-coverage insurance now

Standard homeowners insurance won't cover earthquakes or floods; you need separate policies for all three hazards. Contact your insurer immediately about earthquake coverage, flood insurance through the National Flood Insurance Program, and wildfire protections specific to your neighborhood.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Sonoma County

Top Hazards by Exposure

  1. #1
    EarthquakePrepare
    99th percentile
  2. #2
    FloodPrepare
    99th percentile
  3. #3
    WildfirePrepare
    98th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Risk Advisory: Sonoma County

Risk Verdict

Sonoma County carries an elevated natural disaster risk burden, scoring at the 99th percentile nationally under FEMA's risk model. This risk level calls for more than general awareness: insurance coverage review, a family communication plan, and a prepared go-bag are practical priorities.

Hazard Breakdown

Earthquake risk is Sonoma County's dominant natural hazard, ranked at the 99th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 99th percentile nationally. Additional tracked hazards include wildfire (98th percentile), tornado (15th percentile).

Preparedness Context

Earthquake risk is Sonoma County's leading natural hazard, ranked at the 99th percentile nationally. Securing tall furniture, water heaters, and bookcases to walls with anti-tip hardware is among the simplest and most effective life-safety measures households can take. The county's flood risk at the 99th percentile nationally is a seasonal consideration alongside the year-round earthquake threat, requiring awareness of both hazard types. Sonoma County residents should locate the main gas shutoff valve and keep an appropriate wrench nearby — gas leaks cause a significant share of earthquake-related injuries and fires, and the shutoff step is safe to take immediately after shaking stops.

Regional Context

Sonoma County's composite risk score sits 10.4 points above the California county average, placing it among the more hazard-exposed counties in the state.

Is your household prepared for Sonoma County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Sonoma County, CA?
Sonoma County has a FEMA National Risk Index rating of Relatively High, placing it in the 99th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect Sonoma County?
Sonoma County is evaluated for five major natural hazard types: earthquake (99th percentile), flooding (99th percentile), wildfire (98th percentile), tornado (15th percentile). The highest-risk hazard is earthquake at the 99th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does Sonoma County risk compare to the California average?
Sonoma County's composite risk percentile is 99th, compared to the California state average of 89th percentile. The state's overall risk rating is Relatively Moderate. This means Sonoma County faces higher natural disaster risk than the typical county in California.
Is Sonoma County at risk for earthquake?
Yes, Sonoma County's earthquake risk is at the 99th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Sonoma County is at the 99th percentile.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Why is Sonoma County higher risk than average?
Sonoma County's composite risk score of 99th percentile is above the California state average of 89th percentile. This elevated risk is driven by earthquake exposure (99th percentile), along with flooding and wildfire risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.
By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.