Custer County
Idaho — Natural Disaster Risk Assessment
LowComposite Risk Score
National percentile: 52th
Custer County faces low composite natural disaster risk (NRI Risk Index score 52.4, 52th national percentile), driven primarily by landslide and avalanche 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
| Landslide | High | 7.27 / yr | $414K |
| Avalanche | Very High | 0.23 / yr | $3M |
| Wildfire | Low | 0.00 / yr | $544K |
| Earthquake | Low | 0.03 / yr | $951K |
| Riverine Flood | Low | 0.57 / yr | $5M |
| Winter Weather | Low | 20.28 / yr | $40K |
| Lightning | Low | 28.35 / yr | $115K |
| Cold Wave | Low | 0.84 / yr | $266K |
| Volcanic Activity | Very Low | 0.00 / yr | $1 |
| Heat Wave | Very Low | 0.30 / yr | $40K |
| Strong Wind | Very Low | 0.25 / yr | $82K |
| Drought | Very Low | 93.94 / yr | $387 |
| Ice Storm | Very Low | 0.01 / yr | $2K |
| Tornado | Very Low | 0.13 / yr | $4K |
| Hail | Very Low | 0.08 / yr | $2K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Frequently Asked Questions
What is the overall natural disaster risk for Custer County?
Custer County has a composite FEMA National Risk Index score of 52.4 out of 100, placing it in the Low category and the 52th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Custer County?
The three highest-rated hazards are Landslide (High, $414K EAL), Avalanche (Very High, $3M EAL), Wildfire (Low, $544K EAL). These account for most of the county's expected annual losses.
How does Custer County compare to other Idaho counties?
Custer County ranks #13 of 44 Idaho 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. Custer County's $11M EAL is a statistical average, not a guarantee for any specific year or address.