riskbycounty
FEMA National Risk Index

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 Advisory: Sonoma County

Risk Verdict

Sonoma County carries a relatively high overall disaster risk profile, scoring in the 99th percentile nationally. This places it among the most at-risk counties in the United States. Residents should prioritize comprehensive emergency preparedness, including reviewing insurance coverage and having an evacuation plan.

Hazard Breakdown

Earthquake risk is the dominant hazard for Sonoma County, scoring in the 99th percentile nationally. It is followed by flood risk at the 99th percentile. Additional hazards include wildfire (98th), tornado (15th).

Preparedness Context

With earthquake risk as the top concern, Sonoma County residents should secure heavy furniture and appliances, know how to shut off utilities, and keep emergency supplies accessible. Secondary risks such as flood also warrant attention in household and community preparedness planning. FEMA recommends all households maintain at least 72 hours of food, water, and medication supplies regardless of specific hazard exposure.

Regional Context

Sonoma County is significantly riskier than the average county in California. Its composite risk score is 10.4 points higher than the state average, meaning residents face above-average exposure to natural hazards compared to their neighbors.

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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.

Counties with Similar Risk

Santa Barbara County

California

-0.1

Relatively High

99th percentile

San Mateo County

California

+0.2

Relatively High

99th percentile

Kern County

California

-0.2

Relatively High

99th percentile

By Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & 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.

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