Corson County
South Dakota — Natural Disaster Risk Assessment
Very LowComposite Risk Score
National percentile: 38th
Corson County faces very low composite natural disaster risk (NRI Risk Index score 38.1, 38th national percentile), driven primarily by cold wave and wildfire exposure. Expected annual loss across all 18 hazard types is $7M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Cold Wave | High | 10.11 / yr | $5M |
| Wildfire | Low | 0.00 / yr | $188K |
| Winter Weather | Medium | 16.95 / yr | $108K |
| Hail | Low | 2.65 / yr | $268K |
| Ice Storm | Low | 0.66 / yr | $28K |
| Strong Wind | Low | 1.97 / yr | $213K |
| Drought | Very Low | 33.27 / yr | $12K |
| Tornado | Very Low | 0.57 / yr | $194K |
| Landslide | Very Low | 0.70 / yr | $82 |
| Heat Wave | Very Low | 2.42 / yr | $30K |
| Riverine Flood | Very Low | 1.71 / yr | $1M |
| Lightning | Very Low | 32.24 / yr | $30K |
| Earthquake | Very Low | 0.00 / 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 Corson County?
Corson County has a composite FEMA National Risk Index score of 38.1 out of 100, placing it in the Very Low category and the 38th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Corson County?
The three highest-rated hazards are Cold Wave (High, $5M EAL), Wildfire (Low, $188K EAL), Winter Weather (Medium, $108K EAL). These account for most of the county's expected annual losses.
How does Corson County compare to other South Dakota counties?
Corson County ranks #19 of 66 South Dakota 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. Corson County's $7M EAL is a statistical average, not a guarantee for any specific year or address.