Current Advisory

GNFAC Avalanche Advisory for Wed Nov 26, 2014

Update 3:00 p.m.: AVALANCHE FATALITY


Henderson Peak Avalanche

11/26/14 1430 hours

On November 26, 2014 at about 1331 hours, the Park County Sheriff’s Office received a report of an individual partially buried in an avalanche in the Henderson Peak area near Cooke City. The individual, a snowmobilier, was reported as not breathing. Search & Rescue members were dispatched from Cooke City. CPR was performed but life saving measures were not successful. The individual was pronounced dead at the scene. The incident is under investigation. No further information is available at this time.

Skiers and snowmobiliers are asked to use extreme caution due to the recent heavy snowfall.

Undersheriff Scott Hamilton

Update 1:17 p.m.: Added Video taken this morning at Bridger Bowl.

Update12:00 p.m.: Added Photos to the photo page.

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, November 26 at 7:30 a.m. Today’s advisory is sponsored by Mystery Ranch in partnership with the Friends of the Avalanche Center. This advisory will be updated tomorrow morning. Until they start doing avalanche mitigation, backcountry conditions exist within the ski area boundary of Bridger Bowl and this advisory is relevant to that area.


We are issuing a Backcountry Avalanche Warning for our entire advisory area. Heavy snowfall with strong winds created widespread instability and natural avalanche activity is likely on all slopes. The avalanche danger is rated HIGH in the Bridger, Gallatin and Madison Ranges along with the Lionhead area outside West Yellowstone and mountains around Cooke City. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended and avalanche runout zones should be avoided.

This warning will be terminated by 6:30 a.m. on Friday, November 28.


Mountain Weather: 

The mountains got fire hosed with snow. Estimates are 14+inches in the northern mountains, close to a foot from Big Sky to West Yellowstone and 1 ½ to 2 feet in Cooke City. Winds blew westerly at 20-40 mph, but they are increasing at the ridgetops this morning with speeds of 40-60 mph up Hyalite. The snowfall will taper off this morning as high pressure pushes in. Thanksgiving Day will be sunny with mountain temperatures in the thirties under calm skies.

Snowpack and Avalanche Discussion: 

Bridger Range   Madison Range   Gallatin Range  

Lionhead area near West Yellowstone   Cooke City

Avalanche season is here. Yesterday was an active one and today will be even more so. Skiers triggered slides remotely, hunters got widespread cracking and collapsing and ice climbers turned around when fractures shot across the slope. Mark rode in Cooke City and stuck to the trails, and even then he was very careful about runout zones. Pictures of avalanche activity can be seen here.

This storm was impressive not because of its total snowfall, but from its weight, or snow water equivalency. Since the storm began early yesterday morning 3.3 inches of water fell in the Bridger Range, 2 inches up Hyalite, an inch around Big Sky and West Yellowstone and almost 2 inches in Cooke City. Typically we estimate an inch of water to be a foot of snow, but the warm temperatures skewed this. The snow at the ground is weak and faceted and will avalanche under all this weight. Even though snow depths may vary, the snow structure is similar: an unstable, poorly bonded foundation is struggling to support slabs of storm snow and windblown snow.

When avalanche conditions are bad my recommendation is simple: avoid avalanche terrain. Recent avalanches, whumphing, and shooting cracks are signs that the snowpack is failing. Avalanches are being triggered from far away and can catch unsuspecting travelers at the bottom of a slope. 

Tomorrow looks to be sunny, warm, and a lovely Thanksgiving. Fresh snow and sunny skies are a dangerous combination because nice weather will lure you into thinking the snow is stable. It most certainly is not. Avoid avalanche terrain (slopes steeper than 30 degrees) and runout zones no matter how small. And don’t get gobbled up in an avalanche (I couldn’t resist).

If you get out please let us know what you find. Pictures, snowpits, and a general narrative of conditions are super helpful. Drop us a line at

Have a Smartphone or Tablet? The Friends of the Avalanche Center just published two FREE apps so you can get the latest avalanche information, videos and photos: iOS 8 GNFAC App; Android app


Take a look at our Education Calendar for all our classes being offered.

MSU - Introduction to Avalanches with Field Course

The workshops are held on Wednesday and Thursday evenings, with a field course on Saturday. Different topics are presented each evening. Topics include: avalanche terrain recognition, the affect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures.

December 3, 4 and 6 or 7, 2014:

Snowmobiler Introduction to Avalanches with Field Course

Five hours of lectures are followed by a full day field course. Topics covered include: avalanche terrain recognition, the affect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures.

West Yellowstone: Dec 18 and 19, 2014:

  <<   This is the most recent advisory.