GNFAC Avalanche Advisory for Thu Jan 22, 2015

Not the Current Forecast

Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Thursday, January 22, at 7:30 a.m. Grizzly Outfitters in partnership with the Friends of the Avalanche Center sponsor today’s advisory which is dedicated to Andrew Greicar who was killed in an avalanche outside Cooke City twelve years ago. This advisory does not apply to operating ski areas.


Mountain Weather

This morning with another inversion, temperatures in the mountains were in the mid-teens F in most places but single digits near West Yellowstone and Cooke City. Near Bozeman winds were blowing 20-30 mph from the W, and in all other areas blowing 15-20 mph. Today should have sunshine and temperatures will warm into the 20’s and low 30’s F.


Snowpack and Avalanche Discussion

Southern Gallatin Range   Southern Madison Range  

Lionhead area near West Yellowstone  Cooke City

In areas near West Yellowstone, a layer surface hoar is buried 8 inches deep (photo). Yesterday, Doug and I were hunting for this layer on Lionhead and found it on most slopes. It would not propagate fractures in most of our snowpits (video) and may not be a problem on most slopes for now. HOWEVER, earlier this week two small skier triggered avalanches occurred on this layer. We also found a small avalanche that broke at the ground (photo). It is not a widespread problem but a good reminder to be prepared.

Near Cooke City, small facets near an ice crust are buried 2 feet deep. On Tuesday, I found it mostly below treeline and it only propagated in a few of my stability tests (video). Also on Tuesday, skiers on Barronette Peak experienced collapsing on this layer and triggered a small avalanche (photo1, photo2). It’s not widespread and will only be a problem in small pockets. With a buried weak layer present that has produced some small avalanches, more are possible and the danger is rated MODERATE.


Bridger Range   Northern Gallatin Range

Northern Madison Range

Eric was skiing in Hyalite Canyon yesterday and was surprised to find quite a bit of new snow (photo). He found very stable conditions but observed increasing winds (photo) in the afternoon which continued overnight. Yesterday the Bridger Bowl Ski Patrol easily ski cut small cornices and wind slabs. Except for fresh wind slabs, the snowpack is strong and stable, and there has not been any avalanche activity involving old layers in the snowpack or signs of instability for over a week. Today the avalanche danger is rated MODERATE on wind loaded slopes and LOW on all others.


I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.


Doug wrote a short piece about surface hoar for The Avalanche Review. It won’t be printed until April, but read it on our blog since it’s relevant to the current stability. http://www.mtavalanche.com/blog/some-thoughts-surface-hoar


Avalanche Forecaster’s Beer Social Fundraiser

The Friends of the Avalanche Center and Montana Ale Works are hosting an Avalanche Forecaster’s Beer Social Fundraiser the evening of January 27th. Get more information and buy tickets here: https://www.ticketriver.com/event/14010


AVALANCHE EDUATION and EVENTS

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

Advanced Avalanche Workshop with Field Course, MSU Bozeman, evening lectures 7-9:30 p.m. Wednesday and Thursday, January 28 and 29, with an all-day field session on Saturday. Get more information and register here: https://www.ticketriver.com/event/12445

Gallatin Valley Snowmobile Association Poker Ride, Buck Ridge, Highway 191, Saturday, January 24. Beacon clinic too! More information here: http://gvsa.net/

1-hour Avalanche Awareness for Snowmobilers, West Yellowstone, 7 p.m., Saturday, January 24, Holiday Inn.

1-hour Avalanche Awareness, Dillon, UM Western, 6:30 p.m., Tuesday, January 27.

1-hour Avalanche Awareness for Snowmobilers, West Yellowstone, 7 p.m., Saturday, January 31, Holiday Inn.

1-hour Avalanche Awareness for Snowmobilers, Lewistown, 9 a.m. and 11:30 a.m., Saturday, January 31, Fergus Country Trade Center. More info here: http://www.mtavalanche.com/images/15/thunderstruck-13-premiere-and-avalanche-classes