Lewis County Disaster Risk

Lewis County has a FEMA National Risk Index rating of Relatively Moderate, placing it in the 90th 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.

Lewis County is evaluated for five major natural hazard types: earthquake (97th percentile), flooding (91th percentile), wildfire (77th percentile), tornado (17th percentile). The highest-risk hazard is earthquake at the 97th 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.

Lewis County's composite risk percentile is 90th, compared to the Washington state average of 70th percentile. The state's overall risk rating is Relatively Low. This means Lewis County faces higher natural disaster risk than the typical county in Washington.

Yes, Lewis County's earthquake risk is at the 97th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Lewis County is at the 91th percentile.

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.

Lewis County's composite risk score of 90th percentile is above the Washington state average of 70th percentile. This elevated risk is driven by earthquake exposure (97th 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.