Big Horn County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Big Horn County: 1.
2. Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.

Storm Prediction Center severe weather database, 1950 to 2025.

Every large fire

1. Large fires mapped by the Monitoring Trends in Burn Severity program since 1984: 1,000 acres or more in the West, 500 or more in the East. Prescribed burns are excluded. Acres here are the part of each perimeter inside this place.

Monitoring Trends in Burn Severity (USGS and U.S. Forest Service), 1984 to 2026.

Smoke overhead

1. A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.

NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.

NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.

Every earthquake of magnitude 4 or more within 50 miles

1. Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
2. Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).

USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.

Volcanoes within 100 miles

1. U.S. volcanoes within 100 miles, from the USGS Volcano Hazards Program. The threat category is the USGS 2018 National Volcanic Threat Assessment, which ranks volcanoes by how hazardous their past eruptions were and how many people and how much infrastructure lie near them. It is not a forecast of eruption.

USGS Volcano Hazards Program, retrieved October 30, 2026.

Mapped landslides

Mapped by WY WSGS (427), USGS Conterminous (1).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. Mar 7, 2014Flood$500,000
   National Weather Service narrative

   An ice jam caused flooding around the town of Manderson near the confluence of the Big Horn and Nowood rivers. The National Guard was called in to assist with sandbagging and other protective measures on March 9 and 10.

2. Jun 24, 2011Flood$440,000
   National Weather Service narrative

   Medicine Lodge Creek rose rapidly during the early morning hours of Friday, June 24 as a result of snowmelt in the western Bighorn Mountains. The rising creek completely flooded the campground area and washed out portions of the main road at Medicine Lodge State Archaeological Site northeast of Hyattville. Water from the creek also ran down State Highway 31 which serves as Main Street in Hyattville. The basement of at least one home was inundated by flood waters from the creek. Officials dug a trench across the highway in Hyattville to relieve flood waters on the upstream side of the road. Flooding of agricultural land also occurred in areas between Hyattville and Manderson along…

3. Jul 22, 2011Flood$352,000
   National Weather Service narrative

   Excessive snowmelt runoff caused flooding at Big Horn Lake. The lake elevation hovered about 15 feet above full pool at 3,655 feet. High water neared the level of the US Highway 14A causeway across the southern end of the lake. Wind gusts to 45 mph caused waves that eroded some of the embankment along the causeway and deposited debris onto the highway. On Friday night, July 22, the waves deposited enough debris to necessitate snowplows to come and clear the highway. County Road 20 along the west shore of the lake was inundated and sustained significant damage as a result of the prolonged period of high water.

4. Jun 28, 2011Flood$300,000
   National Weather Service narrative

   Shell Creek and its tributaries caused flooding in and around the community of Shell. The flooding was a result of continued snowmelt in the western Bighorn Mountains as the warmest temperatures of the season were attained. Damage was reported on the Kedesh Guest Ranch and a county road along Trappers Creek.

5. Mar 7, 2014Flood$250,000
   National Weather Service narrative

   Flooding of the Spence Oil Field and other areas north of Greybull occurred along the Big Horn River. Three homes outside the Greybull levee system had minor flooding.

6. Apr 18, 2011Debris Flow, Bighorn Mountains West$237,000
   National Weather Service narrative

   A rockslide on US Highway 14A east of Lovell in the Bighorn Mountains deposited at least 7,500 cubic yards of rock on the roadway. The slide occurred near milepost 73.4 and was witnessed and recorded by at least one person. The slide along with record snowpack kept the road closed beyond its typical Memorial Day opening. The cost of rock removal and road repair exceeded $200,000.

7. Jun 10, 2011Debris Flow, Bighorn Mountains West$165,000
   National Weather Service narrative

   The melting of record snowpack combined with heavy rain to saturate soils in the western Bighorn Mountains. Land below a section of U.S. Highway 14 above Shell Falls gave way near milepost 31.5 making travel on the highway unsafe. The slide, which measured at least 100 feet long, closed the highway for about three weeks.

8. Jun 24, 2011Flood$150,000
   National Weather Service narrative

   Flooding occurred on Shell, Horse, and Trapper creeks as snowmelt runoff increased. Lowland near the creeks and at least one guest ranch were impacted by the rising waters. No bridges were damaged by the high waters but several area roads were inundated and damaged.

9. Jun 28, 2011Flood$145,000
   National Weather Service narrative

   Snowmelt waters traveled down the Greybull River and combined with heavy rain from thunderstorms to create lowland flooding along the river upstream of Greybull. Lane 40 1/2 and Road 5 southwest of Burlington were both inundated by water. The river tried to reroute itself in the vicinity of Road 5. This led county road and bridge employees to construct a new dike to protect one residence and a road.

10. Sep 1, 2007Wildfire, Bighorn Mountains West$100,000
    National Weather Service narrative

    The Bone Creek Wildfire that began on Monday, August 13 continued until Saturday, September 15. The fire scorched approximately 13,670 acres of forest, almost all of which resided within the borders of Big Horn County. The passage of a cold front shortly after midnight on Wednesday, September 5 shifted winds to the north allowing the blaze to jump U.S. Highway 14 west of Shell Falls. Six-tenths of a mile of guardrail burned along the highway which was closed for most of September 5 and 6. Firefighting costs were estimated at $2.8 million. No structures were burned in the blaze. More information about the origins of this wildfire are contained in the August 2007 Storm Data publication.

1. Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.

NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.

All-time high

111°FJun 29, 1919

All-time low

−48°FFeb 5, 1899

Warmest night

75°FJul 12, 2021

Coldest day

−20°FFeb 3, 1989

Wettest day

1.78 inMay 9, 1926

Snowiest day

12.0 inJan 11, 2017

Hottest year

2021mean 49.7°F

Coldest year

1978mean 40.3°F

Wettest year

194011.11 in

Driest year

19192.49 in

Snowiest season

34.4 in1947-48

Station Lovell (USC00485770), 3,847 ft elevation, 15.9 miles from the population centre. Daily records from 1897 to August 31, 2026; 91.8% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.

NOAA NCEI Global Historical Climatology Network Daily.

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.

Neighbouring counties

• Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
• Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
• Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
• Storm events NOAA NCEI Storm Events Database, through 2026.
• Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
• Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
• Weather records NOAA NCEI Global Historical Climatology Network Daily, station USC00485770.
• River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
• Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
• Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
• Volcanoes USGS Volcano Hazards Program, U.S. volcanoes and 2018 threat assessment.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.

Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.