Lyon County
Iowa — Natural Disaster Risk Assessment
Very LowComposite Risk Score
National percentile: 19th
Lyon County faces very low composite natural disaster risk (NRI Risk Index score 19.2, 19th national percentile), driven primarily by hail and drought exposure. Expected annual loss across all 18 hazard types is $11M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Hail | Medium | 6.13 / yr | $3M |
| Drought | Medium | 19.94 / yr | $906K |
| Winter Weather | Medium | 18.42 / yr | $209K |
| Ice Storm | Medium | 1.20 / yr | $303K |
| Tornado | Low | 0.50 / yr | $2M |
| Cold Wave | Low | 8.58 / yr | $1M |
| Landslide | Very Low | 0.07 / yr | $615 |
| Heat Wave | Very Low | 5.11 / yr | $206K |
| Wildfire | Very Low | 0.00 / yr | $20K |
| Riverine Flood | Very Low | 2.36 / yr | $4M |
| Strong Wind | Low | 4.23 / yr | $248K |
| Lightning | Very Low | 38.95 / yr | $47K |
| Earthquake | Very Low | 0.00 / yr | $11K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Frequently Asked Questions
What is the overall natural disaster risk for Lyon County?
Lyon County has a composite FEMA National Risk Index score of 19.2 out of 100, placing it in the Very Low category and the 19th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Lyon County?
The three highest-rated hazards are Hail (Medium, $3M EAL), Drought (Medium, $906K EAL), Winter Weather (Medium, $209K EAL). These account for most of the county's expected annual losses.
How does Lyon County compare to other Iowa counties?
Lyon County ranks #86 of 99 Iowa counties for overall natural disaster risk, with a very low rating.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Lyon County's $11M EAL is a statistical average, not a guarantee for any specific year or address.