Mellette County, SD
FEMA National Risk Index scores, disaster declarations & hazard data
Mellette County has experienced 17 federally declared disasters since 1976, most recently Severe Winter Storms And Snowstorm in 2023. Its overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Mellette County's highest-rated hazards are wildfire, winter weather, and cold wave, with its top risk rated "Relatively Low" by FEMA's National Risk Index. Recorded storm events have decreased 25% over the past five years compared to the prior five-year period. Community vulnerability is elevated (86th percentile nationally), suggesting residents may face greater difficulty recovering from major disasters.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Mellette County has been designated in 17 declarations since 1976, covering 7 disaster types including biological (5), flood (4), severe storm (4).
| Year | Type | Event name |
|---|---|---|
| 2023 | Winter Storm | Severe Winter Storms And Snowstorm |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2019 | Flood | Severe Winter Storm, Snowstorm, And Flooding |
| 2019 | Flood | Severe Storms And Flooding |
| 2010 | Severe Storm | Severe Winter Storm And Snowstorm |
| 2009 | Snowstorm | Severe Winter Storm And Record And Near Record Snow |
Showing the 10 most recent of 17 total declarations since 1976.
Source: FEMA OpenFEMA Disaster Declarations Summaries. A single disaster can produce more than one record per county. Data current through September 2026.
Risk by hazard type
| Hazard | Risk rating | Risk score | Recorded events | Deaths | Prop. damage |
|---|---|---|---|---|---|
| Wildfire | Relatively Low | 83.2 | 0 | 0 | — |
| Inland Flooding | Very Low | 8.1 | 5 | 0 | $10K |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Very Low | 15.9 | 1 | — | — |
| Heat Wave | Very Low | 15.1 | 0 | 0 | — |
| Tornado | Very Low | 19.4 | 0 | 0 | — |
| Hurricane | Not Applicable | — | 0 | 0 | — |
| Hail | Very Low | 22.5 | 44 | 0 | — |
| Strong Wind | Relatively Low | 16.9 | 0 | 0 | — |
| Winter Weather | Relatively Low | 60.2 | 0 | 0 | — |
| Ice Storm | Relatively Low | 33.1 | — | — | — |
| Cold Wave | Relatively Low | 43.4 | — | — | — |
| Lightning | Very Low | 11.2 | 0 | 0 | — |
| Drought | Very Low | 30.8 | 0 | 0 | — |
| Landslide | Very Low | 23.2 | 0 | 0 | — |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic Activity | Not Applicable | — | — | — | — |
Scores are 0–100 percentiles relative to all US counties — higher means more exposed, not that a disaster is likely this year. Event counts: NOAA Storm Events 2016–2026; earthquake counts from USGS ComCat (M3.0+, 1996–2026). See the methodology page for details.
Community vulnerability
Mellette County ranks in the 86th percentile (High) for community vulnerability — a measure of how hard disaster impacts tend to hit residents. Higher vulnerability means more displacement, worse health outcomes, and slower recovery after a disaster.
| SVI theme | Percentile | Vulnerability level |
|---|---|---|
| Overall | 86th | High |
| Socioeconomic status | 93rd | High |
| Household characteristics | 30th | Low |
| Racial & ethnic minority status | 95th | High |
| Housing type & transportation | 84th | High |
Source: CDC/ATSDR Social Vulnerability Index 2022. Percentiles compare counties nationally — higher means more vulnerable relative to other counties. See CDC SVI for full methodology.
Future risk outlook
| Wildfire metric | National percentile | Level |
|---|---|---|
| Burn probability | 78th | Relatively High |
| Risk to homes | 79th | Relatively High |
| Buildings in direct exposure zone | 80.6% | — |
NOAA tracked 49 weather events in this county over 2016–2025: 28 in 2016–20 vs 21 in 2021–25 (-25% — frequency decreasing).
Wildfire: USDA Forest Service Wildfire Risk to Communities (RDS-2020-0016-2) — modeled values, not annual forecasts. See wildfirerisk.org. Inland flood and heat projections pending data availability; coastal sea-level projections are available for select coastal counties below — see the data page.
Nearby counties
Frequently asked questions
What natural hazards pose the greatest risk in Mellette County?
According to the FEMA National Risk Index, the highest-risk hazards in Mellette County, South Dakota are wildfire, winter weather, and cold wave. The county's overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Has Mellette County received federal disaster declarations?
Yes. Mellette County has received 17 federal disaster declarations since 1976, including declarations in 2023. The most common disaster type on record is biological (5 declarations).
Has Mellette County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for Mellette County since the start of 2024. Its most recent declaration on record is Severe Winter Storms And Snowstorm in 2023.
How does Mellette County's natural hazard risk compare to nearby counties?
Among neighboring counties, Todd County, SD has the highest overall natural hazard risk (Very Low) and Jones County, SD has the lowest (Very Low). Mellette County is rated Very Low overall.
How is Mellette County's composite disaster risk index calculated?
Mellette County's composite disaster risk index — officially FEMA's National Risk Index (NRI) — scores every US county on a 0–100 percentile scale across 18 natural hazard types, factoring in expected annual loss, social vulnerability, and community resilience. Mellette County's composite score of 5 means its overall natural hazard risk is higher than 5% of US counties.