Natural disaster risk in Brown County, South Dakota
South Dakota · population 38,265 · FIPS 46013
Overall: relatively low risk
Brown County has a composite risk score of 73.5 out of 100 — higher than 73% of US counties. It ranks 4 of 66 in South Dakota (1 = highest risk). Its highest-rated hazards are winter weather, cold wave, hail.
Drought now: Yes: D1 Moderate Drought, 3 weeks
Yes. On the U.S. Drought Monitor map valid 13 October 2026, 2.3% of Brown County is in D1 Moderate Drought. Some of it has been at D1 or worse for 3 weeks in a row.
Drought in Brown 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 73.5 |
| Expected annual loss About $36.6 million a year, on average, across all 18 hazards. |
Relatively low 77.6 |
| Social vulnerability Higher means people may find it harder to prepare and recover. |
Relatively low 24.1 |
| Community resilience Higher means a stronger ability to prepare, adapt and recover. |
Very high 85.6 |
Risk by hazard
FEMA's risk rating for each of 18 natural hazards in Brown County, highest first. "Not applicable" means the hazard is not modelled here.
| Hazard | Risk rating and score |
|---|---|
| Winter weather | Very high 98 |
| Cold wave | Relatively high 96 |
| Hail | Relatively moderate 86 |
| Strong wind | Relatively moderate 82 |
| Ice storm | Relatively moderate 81 |
| Tornado | Relatively moderate 70 |
| Wildfire | Relatively low 77 |
| Inland (riverine) flooding | Relatively low 63 |
| Heat wave | Relatively low 48 |
| Landslide | Very low 44 |
| Drought | Very low 30 |
| Earthquake | Very low 27 |
| Lightning | Very low 7 |
| Avalanche | Not applicable |
| Coastal flooding | Not applicable |
| Hurricane | Not applicable |
| Tsunami | Not applicable |
| Volcanic activity | Not applicable |
FEMA disaster declarations for Brown County
Federal declarations that designated Brown 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 Brown 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 Brown County, South Dakota?
FEMA's National Risk Index rates the overall risk in Brown County as relatively low, with a score of 73.5 out of 100 (higher than 73% of US counties). That is a comparison with other US counties, not a forecast.
What are the biggest natural hazards in Brown County?
The hazards rated highest for Brown County are winter weather (very high), cold wave (relatively high), hail (relatively moderate).
What is the flood risk in Brown County?
FEMA rates inland (river and rain) flooding risk in Brown County as relatively low. For a specific property, check the FEMA flood map and your local floodplain office.
Has Brown County had a FEMA disaster declaration?
Not since 1 Jan 2024: no FEMA disaster declaration in the records this site read names Brown County.
Is Brown County in a drought?
Yes. On the U.S. Drought Monitor map valid 13 October 2026, 2.3% of Brown County is in D1 Moderate Drought. Some of it has been at D1 or worse for 3 weeks in a row.
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