Custer County
Montana — Natural Disaster Risk Assessment
Very LowComposite Risk Score
National percentile: 42th
Custer County faces very low composite natural disaster risk (NRI Risk Index score 42.1, 42th national percentile), driven primarily by cold wave and winter weather exposure. Expected annual loss across all 18 hazard types is $10M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Cold Wave | Medium | 6.32 / yr | $4M |
| Winter Weather | High | 15.79 / yr | $230K |
| Wildfire | Low | 0.01 / yr | $550K |
| Lightning | Medium | 31.02 / yr | $493K |
| Strong Wind | Medium | 0.97 / yr | $575K |
| Landslide | Very Low | 2.88 / yr | $2K |
| Hail | Low | 1.78 / yr | $184K |
| Heat Wave | Very Low | 2.21 / yr | $162K |
| Riverine Flood | Low | 0.93 / yr | $4M |
| Earthquake | Very Low | 0.00 / yr | $68K |
| Drought | Very Low | 61.45 / yr | $13K |
| Tornado | Very Low | 0.26 / yr | $126K |
| Ice Storm | Very Low | 0.01 / yr | $4K |
| 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 Custer County?
Custer County has a composite FEMA National Risk Index score of 42.1 out of 100, placing it in the Very Low category and the 42th 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 Cold Wave (Medium, $4M EAL), Winter Weather (High, $230K EAL), Wildfire (Low, $550K EAL). These account for most of the county's expected annual losses.
How does Custer County compare to other Montana counties?
Custer County ranks #23 of 56 Montana 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. Custer County's $10M EAL is a statistical average, not a guarantee for any specific year or address.