Sioux County
North Dakota — Natural Disaster Risk Assessment
LowComposite Risk Score
National percentile: 62th
Sioux County faces low composite natural disaster risk (NRI Risk Index score 62.1, 62th national percentile), driven primarily by cold wave and winter weather exposure. Expected annual loss across all 18 hazard types is $12M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Cold Wave | High | 12.95 / yr | $10M |
| Winter Weather | Medium | 19.79 / yr | $123K |
| Wildfire | Low | 0.00 / yr | $236K |
| Hail | Medium | 2.84 / yr | $422K |
| Strong Wind | Medium | 1.97 / yr | $436K |
| Ice Storm | Low | 0.94 / yr | $41K |
| Tornado | Very Low | 0.29 / yr | $201K |
| Drought | Very Low | 22.28 / yr | $5K |
| Lightning | Very Low | 31.37 / yr | $37K |
| Landslide | Very Low | 0.30 / yr | $45 |
| Heat Wave | Very Low | 1.95 / yr | $24K |
| Riverine Flood | Very Low | 0.43 / yr | $726K |
| Earthquake | Very Low | 0.00 / yr | $3K |
| 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 Sioux County?
Sioux County has a composite FEMA National Risk Index score of 62.1 out of 100, placing it in the Low category and the 62th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Sioux County?
The three highest-rated hazards are Cold Wave (High, $10M EAL), Winter Weather (Medium, $123K EAL), Wildfire (Low, $236K EAL). These account for most of the county's expected annual losses.
How does Sioux County compare to other North Dakota counties?
Sioux County ranks #4 of 53 North Dakota 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. Sioux County's $12M EAL is a statistical average, not a guarantee for any specific year or address.