Sioux County Disaster Risk

Sioux County has a FEMA National Risk Index rating of Relatively Low, placing it in the 52th 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.

Sioux County is evaluated for five major natural hazard types: tornado (79th percentile), flooding (49th percentile), wildfire (40th percentile), earthquake (19th percentile). The highest-risk hazard is tornado at the 79th 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.

Sioux County's composite risk percentile is 52th, compared to the Iowa state average of 40th percentile. The state's overall risk rating is Very Low. This means Sioux County faces higher natural disaster risk than the typical county in Iowa.

Yes, Sioux County's tornado risk is at the 79th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Sioux County is at the 49th 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.

Sioux County's composite risk score of 52th percentile is above the Iowa state average of 40th percentile. This elevated risk is driven by tornado exposure (79th percentile). Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.