Day County
South Dakota — Natural Disaster Risk Assessment
Very LowComposite Risk Score
National percentile: 28th
Day County faces very low composite natural disaster risk (NRI Risk Index score 27.6, 28th national percentile), driven primarily by winter weather and strong wind 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
| Winter Weather | Medium | 22.58 / yr | $217K |
| Strong Wind | Medium | 2.91 / yr | $1M |
| Wildfire | Low | 0.00 / yr | $259K |
| Ice Storm | Medium | 0.51 / yr | $243K |
| Cold Wave | Medium | 14.11 / yr | $2M |
| Hail | Low | 3.98 / yr | $416K |
| Landslide | Very Low | 0.15 / yr | $599 |
| Tornado | Low | 0.59 / yr | $695K |
| Heat Wave | Very Low | 2.47 / yr | $65K |
| Riverine Flood | Very Low | 1.11 / yr | $2M |
| Earthquake | Very Low | 0.00 / yr | $12K |
| Drought | Very Low | 0.10 / yr | $126 |
| Lightning | Very Low | 32.54 / yr | $8K |
| 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 Day County?
Day County has a composite FEMA National Risk Index score of 27.6 out of 100, placing it in the Very Low category and the 28th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Day County?
The three highest-rated hazards are Winter Weather (Medium, $217K EAL), Strong Wind (Medium, $1M EAL), Wildfire (Low, $259K EAL). These account for most of the county's expected annual losses.
How does Day County compare to other South Dakota counties?
Day County ranks #26 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. Day County's $7M EAL is a statistical average, not a guarantee for any specific year or address.