GNFAC Avalanche Advisory for Sat Nov 29, 2014

Not the Current Forecast

Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Saturday, November 29 at 7:30 a.m. Today’s advisory is sponsored by the Community Food Co-op in partnership with the Friends of the Avalanche Center. Backcountry conditions exist within the ski area boundary of Bridger Bowl and this advisory is relevant to that area. All the other ski areas are closed to uphill travel.

Mountain Weather

This morning temperatures in most areas were in the high 20s F. In the Bridger Range temperatures were in the low 30s F. Strong winds were blowing 25 mph gusting 40-50 mph from the SW. Temperatures will begin dropping today and should be in the teens F by late afternoon and even colder tonight. Snow should start falling around mid-day. By tomorrow morning most areas will receive 3-5 inches of new snow.

Snowpack and Avalanche Discussion

Bridger Range   Gallatin Range   Madison Range  

Lionhead area near West Yellowstone   Cooke City

Yesterday 2 snowmobilers were caught in an avalanche on the north end of Henderson Mountain above Fisher Creek. One deployed his airbag and was not buried but received minor injuries. The other was buried 7 feet deep but found and dug out quickly by his five partners. He survived and was able to ride back to town. They likely triggered the avalanche as they crossed run out zones under steep slopes. A snowmobiler was killed on Wednesday on the other side of Henderson Mountain when he triggered an avalanche on relatively flat terrain under a steep slope. Read more below.

Also yesterday, the Big Sky Ski Patrol easily triggered many avalanches. All broke at the ground on facets. Some were triggered with explosives and some were remotely triggered as patrollers approached the starting zones on skis. The snowpack at ski areas is identical to the snowpack in the backcountry right now.

Avalanche activity especially remotely triggered avalanches (ones triggered by a person some distance away) is bull’s eye information that the snowpack remains unstable. Strong winds overnight and this morning will make wind-loaded slopes especially unstable. Layering in the snowpack is fairly simple: new snow, 1-3 feet deep, sits on weak facets at the ground. With this snowpack structure, continued avalanche activity, and strong winds, the danger today is HIGH on all wind loaded slopes. All other slopes have a CONSIDERABLE danger.

AVALANCHE FATALITY

(Video, Five Photos, Snowpit)

A snowmobiler died in an avalanche outside Cooke City on Wednesday. The victim, a 31 year old male from North Dakota, remotely triggered a slide on the southwest side of Henderson Mountain off the Miller Road. He was a very experienced rider and had been coming to Cooke City for the last eight years. The victim remotely triggered the avalanche from a flat area which released steeper slopes and buried him under five to six feet of debris. He and his partner had rescue gear and the partner made a heroic effort to dig him out uncovering his head in about 20 minutes. CPR was unsuccessful and Cooke City SAR responded within 10 minutes of the call-out and helped evacuate the victim. The avalanche broke on facets at the ground. The crown was 37 degrees steep and broke two to three feet deep, 300 feet wide and 500 feet vertical. We will have a detailed report in the coming days.

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 mtavalanche@gmail.com.

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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

AVALANCHE EDUATION:

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: https://www.ticketriver.com/event/13089

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: https://www.ticketriver.com/event/12955

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