St. Clair County Disaster Risk

St. Clair County has a FEMA National Risk Index rating of Relatively Moderate, placing it in the 82th 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.

St. Clair County is evaluated for five major natural hazard types: tornado (87th percentile), flooding (86th percentile), earthquake (51th percentile), hurricane (36th percentile), wildfire (34th percentile). The highest-risk hazard is tornado at the 87th 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.

St. Clair County's composite risk percentile is 82th, compared to the Michigan state average of 50th percentile. The state's overall risk rating is Relatively Low. This means St. Clair County faces higher natural disaster risk than the typical county in Michigan.

Yes, St. Clair County's tornado risk is at the 87th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, St. Clair County is at the 86th 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.

St. Clair County's composite risk score of 82th percentile is above the Michigan state average of 50th percentile. This elevated risk is driven by tornado exposure (87th percentile), along with flooding and earthquake risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.