Big Horn County, Wyoming
Natural disaster risk, federal disaster history and flood insurance facts.
Big Horn County, Wyoming has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 69% of US counties. It ranks 12th of 23 counties in Wyoming. The costliest hazards here are inland flooding, cold waves and landslides. FEMA estimates about $8.9 million a year in expected losses, or roughly $771 per resident. Since 1978 it has been included in 2 federal disaster or emergency declarations for natural events (2 major disasters). The most recent was in July 2011 (severe storms, flooding and landslides). Only 16 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 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.
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
- Look for cracks, tilting trees or fences on slopes nearby.
- Ask the county about past slides on the street.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 52.4 | $6M | ||
| Cold wave | 57.9 | $1M | ||
| Landslide | 97.9 | $493K | ||
| Earthquake | 61.4 | $425K | ||
| Tornado | 16.7 | $155K | ||
| Lightning | 37.0 | $126K | ||
| Hail | 26.6 | $88K | ||
| Wildfire | 61.4 | $81K | ||
| Strong wind | 12.0 | $80K | ||
| Drought | 39.3 | $54K | ||
| Winter weather | 45.9 | $49K | ||
| Heat wave | 8.8 | $12K | ||
| Ice storm | 8.9 | $4K | ||
| Avalanche | 32.3 | $110 | ||
| Volcanic activity | 33.2 | $3 |
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 relatively moderate 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
Wyoming also had 5 statewide declarations that did not name single counties.
Storm history since 1958
Tornado risk by county ›The National Weather Service has logged 214 storm reports in Big Horn County since 1958, with 1 death and 3 injuries and about $3.6 million in reported damage. The strongest on record here was an F3 tornado on August 2, 1985.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Aug 2, 1985 | F3 | – | 0 / 0 |
| Jun 26, 1959 | F2 | – | 1 / 1 |
| Jul 4, 1978 | F2 | – | 1 / 0 |
| Jun 3, 1958 | F2 | – | 0 / 0 |
| Jun 12, 1962 | F2 | – | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Jun 24, 2011 | Flood | Hyattville | $540K |
| Mar 7, 2014 | Flood | Rairden | $500K |
| Jul 22, 2011 | Flood | Kane | $352K |
| Jun 28, 2011 | Flood | Greybull | $300K |
| Jun 14, 2006 | Hail | Lovell | $287K |
| Jul 4, 1978 | Tornado | – | $250K |
Source: NOAA Storm Events Database, county-based reports through Jul 16, 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; 5,372 housing units.
Compare in Wyoming
All 23 ›| Largest counties | Overall risk | Top hazard |
|---|---|---|
| Laramie County | Inland flooding | |
| Natrona County | Inland flooding | |
| Campbell County | Cold wave | |
| Sweetwater County | Inland flooding | |
| Fremont County | Inland flooding | |
| Albany County | Inland flooding | |
| Sheridan County | Inland flooding | |
| Park County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Sheridan County | 5 | |
| Park County | 2 | |
| Big Horn County, MT | 7 | |
| Carbon County, MT | 11 | |
| Johnson County | 5 | |
| Washakie County | 3 |
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 $6.2 million a year in FEMA's estimate. Cold wave is second at $1.1 million.
How many federal disasters has Big Horn County had?
Big Horn County has been included in 2 federal disaster or emergency declarations for natural events since 1978, including 2 major disasters. The most recent was Severe Storms, Flooding, and Landslides in July 2011.
Is Big Horn County a high-risk place to live?
Its overall rating is Very Low, 12th highest of 23 in Wyoming. 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 500 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 33 tornadoes in Big Horn County since 1950. The strongest was an F3 tornado on August 2, 1985. The weather service has also logged 62 hail reports and 31 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.