Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, January 19, at 7:30 a.m. Today’s advisory is sponsored by Bountiful Table and World Boards. This advisory does not apply to operating ski areas.
Over the past 24 hours the mountains around Cooke City picked up eight inches of new snow. The Bridger Range received a surprise three inches while the mountains around Big Sky and West Yellowstone picked up a trace to one inch. This morning, mountain temperatures range from the upper teens to mid-twenties F under mostly clear skies. Winds are strong out west blowing 15-30 mph with gusts reaching close to 50 mph in many locations. Today, temperatures will warm into the mid to upper twenties F and winds will remain moderate to strong out of the west. Skies will become mostly cloudy as the day progresses and there is an increasing chance of mountain snow showers by this afternoon. Accumulations of 1-2 inches are possible by this evening.
Cooke City
Cooke City is a snow magnet. Over the past three days Fisher Creek Snotel site has recorded over a foot of snow totaling 1.7 inches of SWE (snow water equivalent). This new snow has provided plenty of ammunition for transport and wind slab development.
Upper elevation slopes leeward to west-southwest winds will be likely locations to encounter wind-drifted snow. With temperatures on the warm side, newly created wind-slabs will be stiff and stubborn. Although not hair trigger, recently formed wind slabs will likely fail under the weight of a skier or rider.
A secondary avalanche concern is a layer of buried surface hoar. The distribution of this layer is questionable, but it likely survived in isolated areas. With over a foot of new snow now capping it, this layer has the ability to catch you by surprise. I would be especially wary of buried surface hoar if skiing or riding on steep, sheltered slopes below treeline.
Today for the mountains around Cooke City, Human triggered avalanches are likely on wind loaded slopes which have a CONSIDERABLE avalanche danger. Non-wind loaded slopes have a MODERATE avalanche danger.
Bridger Range Gallatin Range Madison Range
Lionhead area near West Yellowstone
Winds slabs are today's primary avalanche problem in the mountains around Bozeman, Big Sky and West Yellowstone. An few inches of new snow combined with gusty west winds will create dense slabs in upper elevation, leeward terrain. Recognizing and avoiding wind loaded slopes will be the best way to avoid triggering a slide today.
Another avalanche problem to look out for will be a layer of buried surface hoar. Doug found this layer at Bacon Rind yesterday (video, photo). Another skier also found this layer a few miles north of Bacon Rind. Without a significant load this layer is not a major problem, but will be something to keep an eye out for as we get more snow.
Aside from new snow issues, the snowpack is looking strong over much of our advisory area (video).
Today, human triggered avalanches are possible on steep, wind loaded slopes which have a MODERATE avalanche danger. All other slopes have a LOW avalanche danger.
Doug 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.
AVALANCHE EDUATION and EVENTS
Take a look at our Education Calendar for all our classes being offered.
Introduction to Avalanches with Field Course, MSU Bozeman, evening lectures 7-9:30 p.m. Wednesday and Thursday, January 21 and 22, with an all-day field session on Saturday or Sunday (your choice). Get more information and register here: https://www.ticketriver.com/event/13090
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
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