Rock County Disaster Risk

Rock County has a FEMA National Risk Index rating of Relatively Moderate, placing it in the 86th 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.

Rock County is evaluated for five major natural hazard types: tornado (94th percentile), flooding (88th percentile), earthquake (59th percentile), wildfire (27th percentile), hurricane (15th percentile). The highest-risk hazard is tornado at the 94th 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.

Rock County's composite risk percentile is 86th, compared to the Wisconsin state average of 59th percentile. The state's overall risk rating is Relatively Low. This means Rock County faces higher natural disaster risk than the typical county in Wisconsin.

Yes, Rock County's tornado risk is at the 94th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Rock County is at the 88th 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.

Rock County's composite risk score of 86th percentile is above the Wisconsin state average of 59th percentile. This elevated risk is driven by tornado exposure (94th 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.