Grant County, South Dakota
Natural disaster risk, federal disaster history and flood insurance facts.
Grant County, South Dakota has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 81% of US counties. It ranks 34th of 66 counties in South Dakota. The costliest hazards here are cold waves, inland flooding and tornadoes. FEMA estimates about $11 million a year in expected losses, or roughly $1,420 per resident. Since 1969 it has been included in 20 federal disaster or emergency declarations for natural events (18 major disasters). The most recent was in July 2023 (flooding). Only 8 homes here carry federal flood insurance. Since 1978, federal flood insurance has paid about $314,000 on 41 claims here.
FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.
Top risks in Grant County
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
- 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.
- Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
- Turn on emergency alerts on your phone and keep a weather radio.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Cold wave | 78.4 | $5M | ||
| Inland flooding | 17.3 | $3M | ||
| Tornado | 34.6 | $1M | ||
| Hail | 53.3 | $466K | ||
| Strong wind | 20.2 | $281K | ||
| Ice storm | 62.6 | $230K | ||
| Heat wave | 30.9 | $217K | ||
| Winter weather | 59.0 | $134K | ||
| Wildfire | 54.6 | $94K | ||
| Drought | 35.2 | $64K | ||
| Lightning | 2.6 | $14K | ||
| Earthquake | 6.3 | $9K | ||
| Landslide | 36.3 | $771 |
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 low and community resilience is relatively high in FEMA's measures.
Federal disaster history
Recent disasters nationwide ›Declarations by decade
Federal declarations for natural events that included Grant County. 2020s bar runs to November 2026.
By type
Most recent
Show all 20
South Dakota also had 46 statewide declarations that did not name single counties.
Storm history since 1955
Tornado risk by county ›The National Weather Service has logged 284 storm reports in Grant County since 1955, with 1 death and 2 injuries and about $11.5 million in reported damage. The strongest on record here was an F2 tornado on August 28, 1955.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Aug 28, 1955 | F2 | – | 0 / 0 |
| Aug 3, 1981 | F1 | – | 0 / 0 |
| May 23, 1973 | F1 | – | 0 / 0 |
| May 16, 1962 | F1 | – | 0 / 0 |
| Aug 15, 1973 | F1 | – | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Jun 1, 2019 | Flood | Hiland | $10M |
| Jul 7, 1994 | Hail | Labolt | $550K |
| Jun 11, 2008 | Flash Flood | Hiland | $350K |
| Apr 10, 2023 | Flood | Hiland | $300K |
| Aug 3, 1981 | Tornado | – | $250K |
| Jun 21, 2013 | Thunderstorm Wind | Milbank | $131K |
Source: NOAA Storm Events Database, county-based reports through Jul 19, 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 Grant 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 Grant 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; 3,456 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 |
|---|---|---|
| Codington County | 21 | |
| Roberts County | 22 | |
| Lac qui Parle County, MN | 19 | |
| Day County | 23 | |
| Big Stone County, MN | 18 | |
| Deuel County | 22 |
Common questions about Grant County
What is the biggest natural hazard in Grant County?
Cold wave has the highest expected yearly losses in Grant County, about $5 million a year in FEMA's estimate. Inland flooding is second at $3.2 million.
How many federal disasters has Grant County had?
Grant County has been included in 20 federal disaster or emergency declarations for natural events since 1969, including 18 major disasters. The most recent was Flooding in July 2023.
Is Grant County a high-risk place to live?
Its overall rating is Very Low, 34th 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 Grant County?
Standard home insurance does not cover flooding. About 1 in 500 homes in Grant County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.
How many tornadoes has Grant County had?
NOAA records list 22 tornadoes in Grant County since 1950. The strongest was an F2 tornado on August 28, 1955. The weather service has also logged 129 hail reports and 40 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.