Minnehaha County Disaster Risk

Minnehaha 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.

Minnehaha County is evaluated for five major natural hazard types: tornado (98th percentile), flooding (85th percentile), wildfire (71th percentile), earthquake (37th percentile). The highest-risk hazard is tornado at the 98th 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.

Minnehaha County's composite risk percentile is 90th, compared to the South Dakota state average of 27th percentile. The state's overall risk rating is Very Low. This means Minnehaha County faces higher natural disaster risk than the typical county in South Dakota.

Yes, Minnehaha County's tornado risk is at the 98th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Minnehaha County is at the 85th 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.

Minnehaha County's composite risk score of 90th percentile is above the South Dakota state average of 27th percentile. This elevated risk is driven by tornado exposure (98th 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.