F0/EF0 1 2 3 4 5 · Lines run from where each tornado touched down to where it lifted; dots are short paths. Neighboring counties are outlined.
When tornadoes hit Big Horn County
June has brought the most, 20 of 32. About 88% touched down between 1 pm and 7 pm (Central Standard Time, as the Storm Prediction Center records it).
By decade
More tornadoes in recent decades mostly reflects better detection and reporting (Doppler radar, storm spotters, damage surveys), especially for weak EF0 tornadoes, not necessarily more storms. The 2020s bar covers only 2020 to 2024.
How strong they were
| Rating | Estimated 3-second gust | Tornadoes |
|---|---|---|
| F0 / EF0 | Light damage: 65 to 85 mph (EF scale) | 15 |
| F1 / EF1 | Moderate: 86 to 110 mph | 10 |
| F2 / EF2 | Considerable: 111 to 135 mph | 6 |
| F3 / EF3 | Severe: 136 to 165 mph | 1 |
| F4 / EF4 | Devastating: 166 to 200 mph | 0 |
| F5 / EF5 | Incredible: over 200 mph | 0 |
Tornadoes before February 2007 were rated on the original Fujita (F) scale; since then the National Weather Service uses the Enhanced Fujita (EF) scale. Wind speeds above are EF-scale estimates from damage, not measurements. See what the EF scale means.
The strongest tornadoes in Big Horn County
| Date | Rating | Path length | Path width | Deaths | Injuries |
|---|---|---|---|---|---|
| August 2, 1985 | F3 | 0.2 mi | 10 yd | ||
| June 26, 1959 | F2 | 9.2 mi | 333 yd | 1 | 1 |
| July 4, 1978 | F2 | 5 mi | 200 yd | 1 | |
| June 3, 1958 | F2 | 0.2 mi | 17 yd | ||
| June 12, 1962 | F2 | 0.5 mi | 33 yd | ||
| July 9, 1962 | F2 | 0.5 mi | 17 yd | ||
| July 24, 1967 | F2 | 0.1 mi | 50 yd | ||
| June 5, 1964 | F1 | 2 mi | 100 yd | ||
| June 20, 1974 | F1 | 0.1 mi | 10 yd | ||
| June 20, 1974 | F1 | 0.1 mi | 10 yd |
Deaths and injuries are for each tornado’s whole path, which can cross other counties.
The deadliest
The deadliest tornado to touch Big Horn County was an F2 on June 26, 1959. It killed 1 person and injured 1 along its 9.2-mile path.
Most recent tornadoes
| Date | Rating | Path length | Path width | Deaths | Injuries |
|---|---|---|---|---|---|
| June 12, 2017 | EF0 | 3.1 mi | 30 yd | ||
| May 24, 2014 | EF0 | 0.8 mi | 20 yd | ||
| August 12, 2010 | EF0 | 2.4 mi | 30 yd | ||
| June 1, 2009 | EF1 | 0.4 mi | 35 yd | ||
| June 1, 2005 | F0 | 10 mi | 20 yd | ||
| June 1, 2005 | F0 | 4 mi | 30 yd | ||
| June 1, 2005 | F0 | 4 mi | 30 yd | ||
| June 26, 2001 | F1 | 0.7 mi | 400 yd |
The official database ends with 2024. For storms since then, see the Storm Prediction Center’s reports and your local National Weather Service office.
FEMA’s tornado risk rating
FEMA’s National Risk Index rates the tornado risk in Big Horn County as very low, with a score of 17 out of 100 compared with every other U.S. county. It estimates about 0.24 tornadoes a year here and an expected annual loss of about $155,238 to buildings, people and farming. The index mixes how often tornadoes strike with what is exposed and how well a community can recover, so a busy rural county can rate lower than a less active city.
Neighboring counties
- Johnson County, WY: 22 tornadoes
- Sheridan County, WY: 11 tornadoes
- Big Horn County, MT: 11 tornadoes
- Park County, WY: 10 tornadoes
- Washakie County, WY: 8 tornadoes
- Carbon County, MT: 3 tornadoes
Staying safe
When a tornado warning is issued, act at once. Go to a basement, storm shelter or safe room. With none, use a small windowless room on the lowest floor, as far from outside walls as you can, and cover your head and neck. Mobile homes and cars are not safe places to ride out a tornado: leave early for a sturdy building or shelter. Read the full tornado safety guide and the National Weather Service advice linked below.
Sources
- NOAA Storm Prediction Center: Severe Weather Database, tornadoes 1950 to 2024 (public domain)
- FEMA National Risk Index, tornado county data (December 2025 release)
- NOAA Storm Prediction Center: The Enhanced Fujita Scale (EF scale)
- National Weather Service: Tornado safety
Sources last checked 1 November 2026.