GNFAC Avalanche Forecast for Tue Jan 12, 2016

Not the Current Forecast

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, January 12, at 7:00 AM. Today’s advisory is sponsored by Grizzly Outfitters. This advisory does not apply to operating ski areas.


Mountain Weather

At 5 a.m. under partly cloudy skies, mountain temperatures are in the teens in the north and single digits in the south with westerly winds averaging 20-25 mph and gusting to 40 mph. A moist flow will keep the south partly cloudy with the north getting mostly sun as mountain temperatures warm into the high 20s. Tonight, winds will continue, cloud cover will increase and the mountains could get dusted with snow. Wednesday night and Thursday might deliver a few more flakes, but don’t get your hopes up.


Snowpack and Avalanche Discussion

Bridger Range   Madison Range   Gallatin Range  

Lionhead area near West Yellowstone   Cooke City  

Winds have increased across our forecast area and according to ski patrols at Big Sky and Bridger Bowl they have scoured slopes more than loaded them. Any wind drifts would be small and isolated to ridgelines or gullies. I expect a skier could get unlucky and trigger a small wind slab, but this problem is not widespread.

Facets and depth hoar near the ground are our main concern (video). This layer is weak and continues to break in our stability tests. Since Friday, tests in the Bridger Range, Mt Ellis, Beehive Basin, Bacon Rind, Hebgen Lake and Cooke City all resulted in propagation, a sign that triggering slopes is still possible (video).  On Sunday, Eric and I rode into Tepee Basin to look at an avalanche that was triggered on Friday, low on the slope that buried a snowmobile but not the rider (photo). Many of the bigger, popular slopes that are usually tracked are still pristine. As the days go by without new snow these large stashes of powder become tempting and folks will get away with riding and skiing them because the likelihood of triggering avalanches has decreased. However, the ability to identify these tenuous slopes has become much more difficult. During times like this it is not uncommon to have one slope avalanche while an adjacent one does not. Assessment is tricky and we only really have three choices, one of which is bad:  

  1. Avoid avalanche terrain,
  2. Dig into the snow and test it knowing that any propagation is bad news,
  3. Play dumb and risk it all.  I say “play” dumb because you’ve read this far and are well aware of the dangers.

(I wrote an article on facets and these three points for an upcoming issue of Carve.)

Today, a weak layer of facets near the ground and newly formed wind slabs are creating a MODERATE avalanche danger.      


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


EVENTS and AVALANCHE EDUCATION

A complete calendar of classes can be found HERE.

EVENT in Bozeman: January 19, 5:30-7 p.m. and 7:30-9 p.m., Avi Center Beer Social at Montana Ale Works. This event is a fundraiser for the Friends of the Avalanche Center, $35. Tickets here: https://www.ticketriver.com/event/18542

EVENT at BRIDGER BOWL: February 6, King and Queen of the Ridge. A day of hiking and skiing the Ridge as a fundraiser for the Friends of the Avalanche Center.  Teams and individuals are welcome! More info here: http://bridgerbowl.com/event/king-and-queen-of-the-ridge

Bozeman: January 13, 1hr Avalanche Awareness, REI, 6-7:30 p.m.

Four Corners: January 13, 1hr Avalanche Awareness for Snowmobilers, GVSA Groomer Building, 7-8 p.m.

West Yellowstone: January 9, 23, and 30, 1hr Avalanche Awareness, West Yellowstone Holliday Inn, 7-8:30 p.m.

Livingston: January 14, 1hr Avalanche Awareness, Neptune’s Brewery, 6-7:30 p.m.

Cooke City: January 16, 1hr Avalanche Awareness, Visitor’s Center, 6-7:30 p.m.

January 30, Companion Rescue for Snowmobilers, https://www.ticketriver.com/event/18078

Dillon: January 19, 1hr Avalanche Awareness, UM Western Library, 6:30-8 p.m.

January 23 and 24, Intro to Avalanches w/ Field Course, https://www.ticketriver.com/event/18441

ASMSU Intro to Avalanches w/ Field Course

January 20, 21 and 23 or 24: https://www.ticketriver.com/event/16861

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

Advanced Avalanche Workshop w/ Field Course

January 27, 28, and 30: https://www.ticketriver.com/event/16862

Course content includes: snowpack metamorphism, the mechanics of avalanche failure and fracture, and decision-making. Different topics are covered each evening session. The field session includes snowpack analysis and avalanche rescue scenarios.