Wyoming landslides and avalanches
Every recorded landslide or avalanche record since 1996 · 15 counties with a record
NOAA's Storm Events Database records 98 landslide and avalanche records in Wyoming from 1996 through June 30, 2026, about 4.1 a year since 2000. The deadliest was the February 27, 2009 avalanche in Sublette County and Teton County: 3 deaths. Wyoming ranks 8th of 37 states and territories by count and 10th of 37 per square mile.
Landslides and avalanches in Wyoming, 1996 to 2026
Landslide records per year (NOAA Storm Events); 2026 to June 30, 2026.
- recorded, no damage figure
- under $1 million
- $1 million or more
- $10 million or more
- $100 million or more, or 10 deaths
- $1 billion or more, or 100 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- Records
- 981996 to June 30, 2026
- A year since 2000
- 4.1average
- Deaths
- 5337 injuries
- Damage, 2025 dollars
- $1.7Mas filed
- Busiest year
- 20089 records
Source: NOAA NCEI Storm Events Database, records through June 30, 2026; deaths and damage as filed, damage in 2025 dollars. Search the record at NCEI.
Are landslide and avalanche records common in Wyoming?
Wyoming averages about 4.1 landslide and avalanche records a year since 2000, 8th of 37 states and territories by count. The busiest year on record was 2008 (9). Per 10,000 square miles of land, Wyoming records 10 landslide and avalanche records since 1996, 10th of 37 states and territories by that measure.
Source: NOAA NCEI Storm Events Database, records since 1996, per 10,000 square miles of land area (Census Bureau 2024 Gazetteer; places under 1,000 square miles not ranked). Damage colours: Storm Events damage, 2025 dollars.
Which counties in Wyoming have the most landslide and avalanche records?
Per square mile, Teton County leads Wyoming: 57 days with a landslide or avalanche record since 1996, 14.3 per 1,000 square miles of land. By raw count, Sublette County has the most landslide records (65 since 1996); large counties collect more records simply by covering more ground, so the ranking counts days with a record per unit of area (a storm filed for several forecast zones adds several records but one day).
Source: NOAA NCEI Storm Events Database, days with a record in the county since 1996 per 1,000 square miles of land (Census Bureau 2024 Gazetteer); in brackets, the count of records.
When is the slide season in Wyoming?
47% of its landslide and avalanche records since 1996 fell in January and February. The busiest month is February (25 records).
The values, month by month
Jan 21 · Feb 25 · Mar 9 · Apr 3 · May 4 · Jun 2 · Jul 2 · Aug 2 · Sep 1 · Oct 3 · Nov 2 · Dec 24 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began, since 1996.
What were the deadliest landslide and avalanche records in Wyoming?
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2009-02-27 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains A group of four snowmobilers triggered a mile long, 100 yard wide avalanche in the Deadhorse Creek drainage near Alpine in Lincoln County. The group rode into a draw after dropping off a ridge line and the slab broke loose taking the lives of three men as they tried to outrun the slide. The lone survivor was able to ... | 3 | 0 | – | |
| 2008-01-12 | AvalancheLincoln County and Sublette County · forecast zone Salt River & Wyoming Ranges Three men were killed near Cottonwood Lake when an avalanche enveloped them and their snowmobiles. The slide was estimated to have been one-half mile long, 400 yards wide at the bottom, and covered about 10 acres at an average depth of 10 feet in the runout zone. The snow was powerful enough to uproot or snap trees ... | 3 | 0 | – | |
| 2015-05-17 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains Four skiers were climbing the Sickle Couloir on Mount Moran in Grand Teton National Park on Sunday morning, May 17, when a shallow, wet avalanche broke from above. Three of the four skiers were swept 500 feet downhill over rock and ice. One man was killed on the mountain and another succumbed to his injuries three ... | 2 | 1 | – | |
| 2012-03-07 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains An avalanche on Ranger Peak killed two backcountry skiers Wednesday, March 7. The skiers were found the following day after a family member reported one of them missing. The avalanche occurred at 10,500 feet and swept the skiers 3,000 vertical feet down Waterfalls Canyon. Searchers found one skier 150 feet from the ... | 2 | 0 | – | |
| 2011-04-16 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains Two backcountry skiers were buried by a large avalanche shed from the north face of Nez Perce Peak the night of Saturday, April 16 as the skiers were sheltering in their tents for the night. Late Saturday, April 23, rescuers from the National Park Service and Teton County Search and Rescue discovered the bodies of the ... | 2 | 0 | – | |
| 2016-01-24 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains Two skiers were killed by an avalanche on Ralph's Slide. | 2 | 0 | – | |
| 2006-12-16 | AvalancheLincoln County and Sublette County · forecast zone Salt River & Wyoming Ranges An avalanche at 9,500 foot elevation occurred near Stewart Peak around 3:00 p.m. MST. The slide sent a slab of snow 400 feet long and 300 feet wide down a hillside. Two snowmobilers were caught in the snow which accumulated to nearly 10 feet in depth. One of the men was rescued after 20 minutes beneath the snow, while ... | 1 | 1 | – | |
| 2007-03-10 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains One skier was killed and another injured when an avalanche broke on the west slope of the Teton Mountains and ran for 1,500 feet. The slide occurred in Darby Canyon. | 1 | 1 | – | |
| 2025-01-04 | AvalancheFremont County and 3 more · forecast zone Teton & Gros Ventre Mountains Summary from the USDA FS Bridger Teton Avalanche Center report titled Radio Tower Peak Avalanche Accident: On Saturday, January 4 2025, at approximately 11 am, a group of four skiers unintentionally triggered an avalanche on a north-facing, sparsely treed slope above a steep-walled gully approximately one mile from ... | 1 | 1 | – | |
| 2024-02-09 | AvalancheCarbon County · forecast zone Sierra Madre Range Two snowmobilers west of Battle Pass triggered and were caught in a 2-8 feet deep avalanche the day after heavy snow fell in the area. Strong winds around 50 mph were reported nearby. One fatality was reported. | 1 | 1 | – |
Source: NOAA NCEI Storm Events Database: deaths direct and indirect, as filed by the National Weather Service, summed over each storm (one episode, or one named storm filed by several offices). Storm names from the titles of FEMA declarations that name the storm's counties.
The costliest landslide and avalanche records in Wyoming
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2011-05-14 | Debris FlowLincoln County and Teton County · forecast zone Jackson Hole | 0 | 0 | $656K | |
| 2004-07-18 | Debris FlowPark County and Teton County · forecast zone Yellowstone National Park | 0 | 0 | $430K | |
| 2011-04-18 | Debris FlowBig Horn County and 2 more · forecast zone Bighorn Mountains West | 0 | 0 | $311K | |
| 2008-12-29 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains | 0 | 5 | $21K |
Source: NOAA NCEI Storm Events Database: property and crop damage as estimated by the National Weather Service, in 2025 dollars.
Are landslide and avalanche records becoming more frequent in Wyoming?
Wyoming's count per decade against the whole country's, and its share. NOAA recorded every event type only from 1996, so earlier decades are not comparable; the share of the national total is the fairer comparison across decades.
| Decade | Wyoming | United States | Wyoming's share |
|---|---|---|---|
| 1996-99 | 0 | 98 | 0 |
| 2000s | 24 | 790 | 3.0% |
| 2010s | 55 | 1,304 | 4.2% |
| 2020-26 | 19 | 1,224 | 1.6% |
Source: NOAA NCEI Storm Events Database.
The most recent landslide and avalanche records in Wyoming
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2025-12-22 | AvalancheFremont County and 3 more · forecast zone Teton & Gros Ventre Mountains | 0 | 0 | – | |
| 2025-12-20 | AvalancheFremont County and 3 more · forecast zone Teton & Gros Ventre Mountains | 1 | 0 | – | |
| 2025-12-19 | AvalancheUinta County · forecast zone Uinta | 0 | 0 | – | |
| 2025-07-15 | Debris FlowDayton, Sheridan County | 0 | 0 | – | |
| 2025-01-04 | AvalancheFremont County and 3 more · forecast zone Teton & Gros Ventre Mountains | 1 | 1 | – | |
| 2024-02-09 | AvalancheCarbon County · forecast zone Sierra Madre Range | 1 | 1 | – | |
| 2024-01-14 | AvalancheLincoln County and Sublette County · forecast zone Salt River & Wyoming Ranges | 1 | 0 | – | |
| 2023-02-23 | AvalancheLincoln County and Sublette County · forecast zone Salt River & Wyoming Ranges | 1 | 0 | – | |
| 2022-03-17 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains | 1 | 1 | – | |
| 2022-03-12 | AvalancheCarbon County · forecast zone Sierra Madre Range | 1 | 0 | – | |
| 2021-02-22 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains | 1 | 0 | – | |
| 2021-02-18 | AvalancheSublette County and Teton County · forecast zone Teton & Gros Ventre Mountains | 1 | 0 | – |
Source: NOAA NCEI Storm Events Database, records through June 30, 2026; the newest months are revised by NCEI as reports arrive. Search the record at NCEI.
Federal disaster declarations for landslide and avalanche records in Wyoming
FEMA has declared 2 disasters in Wyoming for landslide and avalanche, counting its incident type and declarations that name landslide or mudslide in the title (FEMA files most storm disasters under Severe Storm); 2 were major disasters, the latest on July 22, 2011.
| Declared | Number | Title | Areas named |
|---|---|---|---|
| 2011-07-22 | DR-4007 | Severe Storms, Flooding, and Landslides | 16 |
| 1978-05-29 | DR-557 | Severe Storms, Flooding & Mudslides | 12 |
Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), through October 2, 2026. OpenFEMA dataset page.
Next
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