Plymouth County Disaster Risk

Plymouth County has a FEMA National Risk Index rating of Relatively Low, placing it in the 49th 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.

Plymouth County is evaluated for five major natural hazard types: tornado (77th percentile), wildfire (71th percentile), flooding (45th percentile), earthquake (14th percentile). The highest-risk hazard is tornado at the 77th 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.

Plymouth County's composite risk percentile is 49th, compared to the Iowa state average of 40th percentile. The state's overall risk rating is Very Low. This means Plymouth County faces higher natural disaster risk than the typical county in Iowa.

Yes, Plymouth County's tornado risk is at the 77th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Plymouth County is at the 45th 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.

Plymouth County's composite risk score of 49th percentile is above the Iowa state average of 40th percentile. This elevated risk is driven by tornado exposure (77th percentile), along with wildfire risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.