Big Horn County, Montana
Natural disaster risk, federal disaster history and flood insurance facts.
Big Horn County, Montana has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 57% of US counties. It ranks 13th of 56 counties in Montana. The costliest hazards here are inland flooding, wildfires and strong wind. FEMA estimates about $11 million a year in expected losses, or roughly $863 per resident. Since 1978 it has been included in 7 federal disaster or emergency declarations for natural events (5 major disasters). The most recent was in April 2026 (severe winter storm and straight-line winds). Only 6 homes here carry federal flood insurance. Since 1978, federal flood insurance has paid about $245,000 on 16 claims here.
FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.
Top risks in Big Horn 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.
- Clear dry plants and debris within 5 feet of the house.
- Get home insurance quotes early; availability varies by area.
- Secure outdoor furniture and trash bins before storms.
- Have trees near the house checked.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 55.1 | $4M | ||
| Wildfire | 94.8 | $2M | ||
| Strong wind | 95.9 | $2M | ||
| Cold wave | 76.9 | $2M | ||
| Lightning | 83.2 | $493K | ||
| Winter weather | 88.5 | $212K | ||
| Hail | 51.8 | $164K | ||
| Heat wave | 34.9 | $103K | ||
| Earthquake | 39.6 | $86K | ||
| Tornado | 12.1 | $54K | ||
| Drought | 38.5 | $34K | ||
| Landslide | 73.8 | $5K | ||
| Ice storm | 12.5 | $4K | ||
| Avalanche | 36.3 | $101 | ||
| Volcanic activity | 9.4 | $0 |
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 Big Horn County. 2020s bar runs to November 2026.
By type
Most recent
Montana also had 36 statewide declarations that did not name single counties.
Storm history since 1956
Tornado risk by county ›The National Weather Service has logged 444 storm reports in Big Horn County since 1956, with 6 deaths and 18 injuries and about $4.7 million in reported damage. The strongest on record here was an F1 tornado on June 21, 1984.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Jun 21, 1984 | F1 | – | 0 / 0 |
| Jun 21, 1991 | F1 | – | 0 / 0 |
| Jul 9, 1991 | F1 | – | 0 / 0 |
| Jun 21, 1984 | F1 | – | 0 / 0 |
| Jun 22, 1996 | F1 | Hardin | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| May 21, 2011 | Flood | Big Horn Wye | $4M |
| Jun 21, 1984 | Tornado | – | $250K |
| Jun 21, 1991 | Tornado | – | $250K |
| Jul 5, 1998 | Hail | Hardin | $100K |
| Jul 9, 1991 | Tornado | – | $25K |
| Jul 23, 2000 | Thunderstorm Wind | Hardin | $10K |
Source: NOAA Storm Events Database, county-based reports through Jun 27, 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 Big Horn 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 Big Horn 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; 4,527 housing units.
Compare in Montana
All 56 ›| Largest counties | Overall risk | Top hazard |
|---|---|---|
| Yellowstone County | Inland flooding | |
| Gallatin County | Earthquake | |
| Missoula County | Inland flooding | |
| Flathead County | Inland flooding | |
| Cascade County | Inland flooding | |
| Lewis and Clark County | Cold wave | |
| Ravalli County | Wildfire | |
| Silver Bow County | Cold wave |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Yellowstone County | 12 | |
| Sheridan County, WY | 5 | |
| Big Horn County, WY | 2 | |
| Carbon County | 11 | |
| Rosebud County | 13 | |
| Powder River County | 10 | |
| Treasure County | 9 |
Common questions about Big Horn County
What is the biggest natural hazard in Big Horn County?
Inland flooding has the highest expected yearly losses in Big Horn County, about $4.5 million a year in FEMA's estimate. Wildfire is second at $2 million.
How many federal disasters has Big Horn County had?
Big Horn County has been included in 7 federal disaster or emergency declarations for natural events since 1978, including 5 major disasters. The most recent was Severe Winter Storm and Straight-Line Winds in April 2026.
Is Big Horn County a high-risk place to live?
Its overall rating is Relatively Low, 13th highest of 56 in Montana. 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 Big Horn County?
Standard home insurance does not cover flooding. About 1 in 1000 homes in Big Horn 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 Big Horn County had?
NOAA records list 10 tornadoes in Big Horn County since 1950. The strongest was an F1 tornado on June 21, 1984. The weather service has also logged 248 hail reports and 24 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.