Natural disaster risk in Dewey County, South Dakota
South Dakota · population 5,228 · FIPS 46041
Overall: relatively low risk
Dewey County has a composite risk score of 78.7 out of 100 — higher than 78% of US counties. It ranks 2 of 66 in South Dakota (1 = highest risk). Its highest-rated hazards are cold wave, winter weather, ice storm.
Drought now: Yes: D2 Severe Drought, 14 weeks
Yes. On the U.S. Drought Monitor map valid 13 October 2026, 52.87% of Dewey County is in D2 Severe Drought. Some of it has been at D2 or worse for 14 weeks in a row. In all, 100% of the county is in drought (D1 to D4).
Drought in Dewey County: the last 52 weeks · droughtmonitor.unl.edu
The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration. Map courtesy of NDMC.
Risk, loss, vulnerability and resilience
| Measure | Rating and score |
|---|---|
| Overall risk Expected annual loss, adjusted for social vulnerability and community resilience. |
Relatively low 78.7 |
| Expected annual loss About $22.1 million a year, on average, across all 18 hazards. |
Relatively low 63.6 |
| Social vulnerability Higher means people may find it harder to prepare and recover. |
Very high 98.7 |
| Community resilience Higher means a stronger ability to prepare, adapt and recover. |
Very low 6.9 |
Risk by hazard
FEMA's risk rating for each of 18 natural hazards in Dewey County, highest first. "Not applicable" means the hazard is not modelled here.
| Hazard | Risk rating and score |
|---|---|
| Cold wave | Very high 99 |
| Winter weather | Relatively high 85 |
| Ice storm | Relatively moderate 65 |
| Wildfire | Relatively low 82 |
| Hail | Relatively low 57 |
| Strong wind | Relatively low 22 |
| Landslide | Very low 31 |
| Drought | Very low 28 |
| Tornado | Very low 24 |
| Heat wave | Very low 23 |
| Inland (riverine) flooding | Very low 17 |
| Lightning | Very low 16 |
| Earthquake | Very low 12 |
| Avalanche | Not applicable |
| Coastal flooding | Not applicable |
| Hurricane | Not applicable |
| Tsunami | Not applicable |
| Volcanic activity | Not applicable |
FEMA disaster declarations for Dewey County
Federal declarations that designated Dewey County, since 1 Jan 2024 (the period this site keeps from OpenFEMA). Older declarations are in FEMA's own dataset.
Not since 1 Jan 2024: no FEMA disaster declaration in the records this site read names Dewey County.
All FEMA declarations in South Dakota, with estimated apply-by dates · Open FEMA deadlines
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s). Dataset: Disaster Declarations Summaries - v2.
How to read these ratings
- Ratings run in five steps: very low, relatively low, relatively moderate, relatively high and very high. They compare a county with every other US county; they are not a measure of danger on their own.
- Scores run from 0 to 100 and are national percentiles. The bar shows the score: a score of 80 means a higher value than 80% of US counties.
- Overall risk combines the expected annual loss with social vulnerability and community resilience.
- Expected annual loss is the average yearly loss to buildings, people and agriculture the model expects from all 18 hazards.
- Social vulnerability describes how hard it may be for people to prepare for and recover from a disaster. Higher is worse.
- Community resilience describes a community's ability to prepare, adapt and recover. Higher is better.
- "Not applicable" means FEMA does not model that hazard there (for example, hurricanes far inland).
About this data
Source: FEMA National Risk Index, version 1.20, released December 2025, published by the Federal Emergency Management Agency (US public domain). About the National Risk Index. The index is a model of relative risk built from historical hazard records, what is exposed and community factors. It is not a forecast, it does not describe any single property, and it is not insurance or financial advice. For decisions about a specific address, check FEMA's flood maps and your local emergency management office.
Questions
What is the natural disaster risk in Dewey County, South Dakota?
FEMA's National Risk Index rates the overall risk in Dewey County as relatively low, with a score of 78.7 out of 100 (higher than 78% of US counties). That is a comparison with other US counties, not a forecast.
What are the biggest natural hazards in Dewey County?
The hazards rated highest for Dewey County are cold wave (very high), winter weather (relatively high), ice storm (relatively moderate).
What is the flood risk in Dewey County?
FEMA rates inland (river and rain) flooding risk in Dewey County as very low. For a specific property, check the FEMA flood map and your local floodplain office.
Has Dewey County had a FEMA disaster declaration?
Not since 1 Jan 2024: no FEMA disaster declaration in the records this site read names Dewey County.
Is Dewey County in a drought?
Yes. On the U.S. Drought Monitor map valid 13 October 2026, 52.87% of Dewey County is in D2 Severe Drought. Some of it has been at D2 or worse for 14 weeks in a row. In all, 100% of the county is in drought (D1 to D4).
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