Mellette County, South Dakota
Natural disaster risk, federal disaster history and flood insurance facts.
Mellette County, South Dakota has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 95% of US counties. It ranks 58th of 66 counties in South Dakota. The costliest hazards here are inland flooding, cold waves and wildfires. FEMA estimates about $1.9 million a year in expected losses, or roughly $992 per resident. Since 1976 it has been included in 12 federal disaster or emergency declarations for natural events (10 major disasters). The most recent was in February 2023 (severe winter storms and snowstorm). No homes here carry federal flood insurance.
FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.
Top risks in Mellette County
- Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
- Price a flood policy now. Most new federal policies take 30 days to start.
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
- Clear dry plants and debris within 5 feet of the house.
- Get home insurance quotes early; availability varies by area.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 8.1 | $657K | ||
| Cold wave | 43.4 | $443K | ||
| Wildfire | 83.2 | $348K | ||
| Tornado | 19.4 | $133K | ||
| Strong wind | 16.9 | $88K | ||
| Winter weather | 60.2 | $54K | ||
| Hail | 22.5 | $48K | ||
| Ice storm | 33.1 | $23K | ||
| Lightning | 11.2 | $22K | ||
| Heat wave | 15.1 | $21K | ||
| Drought | 30.8 | $16K | ||
| Earthquake | 15.9 | $11K | ||
| Landslide | 23.2 | $97 |
Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is very high and community resilience is very low in FEMA's measures.
Federal disaster history
Recent disasters nationwide ›Declarations by decade
Federal declarations for natural events that included Mellette County. 2020s bar runs to November 2026.
By type
Most recent
Show all 12
South Dakota also had 46 statewide declarations that did not name single counties.
Storm history since 1966
Tornado risk by county ›The National Weather Service has logged 307 storm reports in Mellette County since 1966, with 0 deaths and 1 injury and about $992,500 in reported damage. The strongest on record here was an F2 tornado on June 4, 1971.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Jun 4, 1971 | F2 | – | 0 / 0 |
| May 19, 1974 | F1 | – | 0 / 0 |
| Jul 4, 1973 | F1 | – | 0 / 0 |
| Sep 24, 1986 | F0 | – | 0 / 0 |
| Jul 10, 1987 | F0 | – | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| May 19, 1974 | Tornado | – | $250K |
| Aug 20, 2000 | Thunderstorm Wind | White River | $200K |
| Jun 5, 2008 | Flood | Mosher | $100K |
| Jul 9, 2007 | Thunderstorm Wind | White River | $75K |
| Jul 22, 2012 | Thunderstorm Wind | Wood | $60K |
| May 3, 1994 | Hail | Mosherand | $55K |
Source: NOAA Storm Events Database, county-based reports through Jun 29, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.
Flood insurance in Mellette County
Check your address flood zone ›National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.
Homes in Mellette County
Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 779 housing units.
Compare in South Dakota
All 66 ›| Largest counties | Overall risk | Top hazard |
|---|---|---|
| Minnehaha County | Tornado | |
| Pennington County | Inland flooding | |
| Lincoln County | Tornado | |
| Brown County | Cold wave | |
| Brookings County | Inland flooding | |
| Meade County | Inland flooding | |
| Codington County | Inland flooding | |
| Lawrence County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Todd County | 11 | |
| Tripp County | 18 | |
| Lyman County | 14 | |
| Bennett County | 13 | |
| Jackson County | 20 | |
| Jones County | 13 |
Common questions about Mellette County
What is the biggest natural hazard in Mellette County?
Inland flooding has the highest expected yearly losses in Mellette County, about $657,180 a year in FEMA's estimate. Cold wave is second at $442,542.
How many federal disasters has Mellette County had?
Mellette County has been included in 12 federal disaster or emergency declarations for natural events since 1976, including 10 major disasters. The most recent was Severe Winter Storms and Snowstorm in February 2023.
Is Mellette County a high-risk place to live?
Its overall rating is Very Low, 58th highest of 66 in South Dakota. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.
Do I need flood insurance in Mellette County?
Standard home insurance does not cover flooding. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.
How many tornadoes has Mellette County had?
NOAA records list 12 tornadoes in Mellette County since 1950. The strongest was an F2 tornado on June 4, 1971. The weather service has also logged 164 hail reports and 14 floods here.
Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.