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

King County Disaster Risk

King County, Washington

FEMA Risk Rating

Very High

National Percentile

100th

of 3,144 counties

State Rank

#1

of 39 (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 Low

Higher than 79% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 73% of US counties

Earthquake

Seismic activity and ground shaking risk

Very High

Higher than 100% of US counties

Risk Overview

About Natural Disaster Risk in King County, Washington

King County faces very high disaster risk

King County's composite risk score of 99.68 places it in the "Very High" category, significantly above the national average. This score reflects substantial exposure to multiple major hazards, particularly earthquakes and flooding that threaten the region's dense population and critical infrastructure.

Riskiest county in Washington state

With a score of 99.68, King County ranks as Washington's most hazard-prone county, far exceeding the state average of 70.01. This distinction reflects the region's position on the Cascade volcanic arc and proximity to major fault systems and flood-prone waterways.

King County significantly outpaces neighbors

King County's risk score of 99.68 dwarfs nearby Kitsap County (92.30) and Mason County (85.34), making it a clear outlier in the Puget Sound region. The difference is driven largely by King County's extreme earthquake risk (99.90) and severe flood vulnerability affecting millions of residents.

Earthquakes and floods dominate King's risks

King County faces nearly certain earthquake exposure (99.90 risk score) due to the Cascadia Subduction Zone and local fault systems, plus major flood risks (99.46) from the Green, White, and Cedar Rivers affecting low-lying communities. Wildfires (79.45) also threaten suburban areas during dry seasons, though they rank below seismic and hydrologic hazards.

Essential coverage for King County homes

Standard homeowners insurance doesn't cover earthquakes or floods, making separate earthquake and flood policies critical for King County residents. Consult a local insurance agent about coverage limits that reflect your home's location—especially if you're near rivers, on soft soils, or in older structures vulnerable to seismic damage.

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

Preparedness Guide

What to Prepare for in King County

Top Hazards by Exposure

  1. #1
    EarthquakePrepare
    100th percentile
  2. #2
    FloodPrepare
    99th percentile
  3. #3
    WildfirePrepare
    79th percentile

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

Local Resources

Risk Advisory: King County

Risk Verdict

At the 100th percentile nationally, King County ranks in the very top tier for natural disaster risk across all U.S. counties. Proactive preparedness — not reactive response — is key to managing life in one of the country's higher-risk counties; King County residents should plan accordingly.

Hazard Breakdown

Earthquake risk is King County's dominant natural hazard, ranked at the 100th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 99th percentile nationally. Additional tracked hazards include wildfire (79th percentile), tornado (73th percentile).

Preparedness Context

At the 100th percentile nationally for earthquake exposure, King County households benefit from practicing Drop, Cover, and Hold On — the protocol that minimizes injury during shaking. Getting under a sturdy table or desk and holding on until shaking stops is the key action. Flood at the 99th percentile nationally is a separate hazard dimension for King County that requires different protective strategies from earthquake preparedness. Building age matters for earthquake risk in King County: structures built before local seismic code adoption are statistically more vulnerable. Contacting the local building department about retrofit programs can reveal whether your structure qualifies for mitigation assistance.

Regional Context

At 29.7 points above the Washington state average, King County carries meaningfully higher natural disaster exposure than a typical Washington county.

Is your household prepared for King 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 King County, WA?
King 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 King County?
King County is evaluated for five major natural hazard types: earthquake (100th percentile), flooding (99th percentile), wildfire (79th percentile), tornado (73th 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 King County risk compare to the Washington average?
King County's composite risk percentile is 100th, compared to the Washington state average of 70th percentile. The state's overall risk rating is Relatively Low. This means King County faces higher natural disaster risk than the typical county in Washington.
Is King County at risk for earthquake?
Yes, King County's earthquake risk is at the 100th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, King 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 King County higher risk than average?
King County's composite risk score of 100th percentile is above the Washington state average of 70th 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

Pierce County

Washington

-1.1

Relatively High

99th percentile

Snohomish County

Washington

-1.8

Relatively High

98th percentile

Grays Harbor County

Washington

-2.7

Relatively High

97th percentile

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.

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