riskbycounty
FEMA National Risk Index

Alameda County Disaster Risk

Alameda County, California

FEMA Risk Rating

Very High

National Percentile

100th

of 3,144 counties

State Rank

#5

of 58 (1 = highest risk)

Flood Risk

100th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very High

Higher than 100% 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

Relatively Low

Higher than 66% of US counties

Earthquake

Seismic activity and ground shaking risk

Very High

Higher than 100% of US counties

Risk Advisory: Alameda County

Risk Verdict

Alameda County carries a very high overall disaster risk profile, scoring in the 100th 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 Alameda County, scoring in the 100th percentile nationally. It is followed by flood risk at the 100th percentile. Additional hazards include wildfire (98th), tornado (66th).

Preparedness Context

With earthquake risk as the top concern, Alameda 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

Alameda County is significantly riskier than the average county in California. Its composite risk score is 11.1 points higher than the state average, meaning residents face above-average exposure to natural hazards compared to their neighbors.

Is your home insured against Alameda County's risks?

Compare home and flood insurance quotes in minutes.

Get Quotes →

Sponsored

High flood risk area

Learn about NFIP flood insurance coverage for your property.

Learn More →

Frequently Asked Questions

What is the natural disaster risk in Alameda County, CA?
Alameda County has a FEMA National Risk Index rating of Very High, placing it in the 100th 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 Alameda County?
Alameda County is evaluated for five major natural hazard types: earthquake (100th percentile), flooding (100th percentile), wildfire (98th percentile), tornado (66th percentile). The highest-risk hazard is earthquake at the 100th 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 Alameda County risk compare to the California average?
Alameda County's composite risk percentile is 100th, compared to the California state average of 89th percentile. The state's overall risk rating is Relatively Moderate. This means Alameda County faces higher natural disaster risk than the typical county in California.
Is Alameda County at risk for earthquake?
Yes, Alameda County's earthquake risk is at the 100th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Alameda County is at the 100th 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 Alameda County higher risk than average?
Alameda County's composite risk score of 100th percentile is above the California state average of 89th percentile. This elevated risk is driven by earthquake exposure (100th percentile), along with flooding and wildfire and tornado 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

Orange County

California

+0.0

Very High

100th percentile

Santa Clara County

California

-0.0

Very High

100th percentile

San Bernardino County

California

+0.1

Very High

100th 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.

Explore more data for Alameda County

Property TaxCost of LivingCrime RateIncomeHealthSchoolsWater QualityWeatherCounty Score