Story County
Iowa — Natural Disaster Risk Assessment
LowComposite Risk Score
National percentile: 69th
Story County faces low composite natural disaster risk (NRI Risk Index score 68.8, 69th national percentile), driven primarily by drought and tornado exposure. Expected annual loss across all 18 hazard types is $36M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Drought | High | 6.44 / yr | $4M |
| Tornado | High | 0.59 / yr | $10M |
| Winter Weather | High | 15.89 / yr | $533K |
| Hail | Medium | 6.20 / yr | $2M |
| Strong Wind | Medium | 6.05 / yr | $1M |
| Riverine Flood | Low | 2.68 / yr | $16M |
| Ice Storm | Medium | 0.68 / yr | $209K |
| Lightning | Low | 42.95 / yr | $380K |
| Landslide | Very Low | 0.07 / yr | $1K |
| Cold Wave | Low | 7.79 / yr | $692K |
| Earthquake | Very Low | 0.00 / yr | $142K |
| Wildfire | Very Low | 0.00 / yr | $19K |
| Hurricane | Very Low | 0.01 / yr | $5K |
| Heat Wave | Very Low | 5.37 / yr | $37K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | 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 Story County?
Story County has a composite FEMA National Risk Index score of 68.8 out of 100, placing it in the Low category and the 69th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Story County?
The three highest-rated hazards are Drought (High, $4M EAL), Tornado (High, $10M EAL), Winter Weather (High, $533K EAL). These account for most of the county's expected annual losses.
How does Story County compare to other Iowa counties?
Story County ranks #9 of 99 Iowa counties for overall natural disaster risk, with a 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. Story County's $36M EAL is a statistical average, not a guarantee for any specific year or address.