Sully County, SD
FEMA National Risk Index scores, disaster declarations & hazard data
Sully County has experienced 16 federally declared disasters since 1976, most recently Covid-19 in 2020. Its overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Sully County's highest-rated hazards are wildfire, cold wave, and winter weather, with its top risk rated "Relatively Low" by FEMA's National Risk Index. Recorded storm events have decreased 66% over the past five years compared to the prior five-year period. Community vulnerability is relatively low (3rd percentile nationally), indicating stronger recovery capacity than most US counties.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Sully County has been designated in 16 declarations since 1976, covering 6 disaster types including flood (6), severe storm (5), biological (2).
| Year | Type | Event name |
|---|---|---|
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2019 | Flood | Severe Winter Storm, Snowstorm, And Flooding |
| 2017 | Severe Storm | Severe Winter Storm |
| 2011 | Flood | Flooding |
| 2010 | Severe Storm | Severe Winter Storm |
| 2010 | Flood | Flooding |
| 2005 | Severe Storm | Severe Storm |
| 2005 | Coastal Storm | Hurricane Katrina Evacuation |
| 1997 | Severe Storm | Severe Winter Storms And Blizzard Conditions |
Showing the 10 most recent of 16 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 | 70.6 | 0 | 0 | — |
| Inland Flooding | Very Low | 14.1 | 4 | 0 | $181K |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Very Low | 6.8 | 2 | — | — |
| Heat Wave | Very Low | 7.5 | 6 | 0 | — |
| Tornado | Very Low | 14.6 | 1 | 0 | — |
| Hurricane | Not Applicable | — | 0 | 0 | — |
| Hail | Relatively Low | 34.7 | 28 | 0 | — |
| Strong Wind | Very Low | 8.9 | 0 | 0 | — |
| Winter Weather | Relatively Low | 50.1 | 0 | 0 | — |
| Ice Storm | Very Low | 24.2 | — | — | — |
| Cold Wave | Relatively Low | 51.1 | — | — | — |
| Lightning | Very Low | 2 | 0 | 0 | — |
| Drought | Relatively Low | 44.9 | 0 | 0 | — |
| Landslide | Very Low | 7 | 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
Sully County ranks in the 3rd percentile (Very low) 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 | 3rd | Very low |
| Socioeconomic status | 3rd | Very low |
| Household characteristics | 22nd | Very low |
| Racial & ethnic minority status | 21st | Very low |
| Housing type & transportation | 4th | Very low |
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 | 53rd | Relatively Moderate |
| Risk to homes | 62nd | Relatively High |
| Buildings in direct exposure zone | 59.3% | — |
NOAA tracked 39 weather events in this county over 2016–2025: 29 in 2016–20 vs 10 in 2021–25 (-66% — 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 Sully County?
According to the FEMA National Risk Index, the highest-risk hazards in Sully County, South Dakota are wildfire, cold wave, and winter weather. The county's overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Has Sully County received federal disaster declarations?
Yes. Sully County has received 16 federal disaster declarations since 1976, including declarations in 2020. The most common disaster type on record is flood (6 declarations).
Has Sully County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for Sully County since the start of 2024. Its most recent declaration on record is Covid-19 in 2020.
How does Sully County's natural hazard risk compare to nearby counties?
Among neighboring counties, Dewey County, SD has the highest overall natural hazard risk (Relatively Low) and Stanley County, SD has the lowest (Very Low). Sully County is rated Very Low overall.
How is Sully County's composite disaster risk index calculated?
Sully 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. Sully County's composite score of 6 means its overall natural hazard risk is higher than 6% of US counties.