Good morning and Merry Christmas. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, December 25 at 7:30 a.m. This advisory is sponsored by Bridger Bowl in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
Unseasonably warm and dry conditions will remain over southwest Montana through Christmas Day. Currently mountain temperatures are in the high teens to mid 20s and winds are blowing out of the west at 10-20 mph. Today temperatures will climb into the mid 30s under partly cloudy skies. Winds will gradually increase from the west blowing 20-30 mph by this evening. A weak cold front will arrive later tonight bringing cloudy and cooler conditions tomorrow. Unfortunately very little precipitation will be associated with this front.
The Gallatin and Madison Ranges, the Lionhead area near West Yellowstone and mountains around Cooke City:
Big snow appears to be number one on the Christmas wish list, but unfortunately this wish is backordered. As a result, the snowpack has not changed much over the past few days. Strong winds out of the west continue to load slopes on the east half of the compass, forming stiff and punchy wind slabs, specifically on upper elevation slopes below ridgelines. While recently formed slabs may feel strong and supportable, they likely rest over lower density faceted snow, making them sensitive to the weight of a skier or rider.
Yesterday, the Moonlight Basin Ski Patrol triggered multiple avalanches during control work, some of which failed on facets near the ground. Also, skiers in Beehive Basin on Friday triggered an avalanche on a west facing slope around 9,000 ft (photo1, photo2). This slide also failed on facets near the ground and occurred on a non-wind loaded slope.
Today, wind slabs resting over weak faceted snow make human triggered avalanches likely in wind loaded terrain where the avalanche danger is rated CONSIDERABLE. Non-wind loaded slopes have MODERATE avalanche danger.
The Bridger Range:
Though the weather outside is delightful
The rocks under the snow are frightful
So, if you're heading to Bridger Bowl
Do a dance for snow, snow, and more snow
Bottom line is the Bridger Range just doesn't have enough snow to harbor widespread instability (photo). The limited snow that did fall during last week's storm has either been blown to North Dakota or has formed stiff and punchy wind slabs below the ridgelines. Yesterday, Mark and I skied Hidden Gully to the Apron and found wind slabs to be isolated and stubborn. However, we both felt it could be possible to trigger a wind loaded slope, specifically in steep terrain below ridgelines.
Today - human triggered avalanches are possible on wind loaded slopes where the avalanche danger is rated MODERATE. Non-wind loaded slopes have a LOW avalanche Danger.
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.
EVENTS/EDUCATION
To check out all our education programs: http://www.mtavalanche.com/workshops/calendar
BOZEMAN
Women’s 1-hour Avalanche Awareness Lecture. Wednesday, January 4, 6:30- 8 p.m. at REI.
Snowmobiler Introduction to Avalanches with Field Course. Lectures on Saturday, January 7, with an all day field session Sunday, January 8. Advanced registration IS REQUIRED.
1-hr Avalanche Awareness Lecture. Wednesday, January 11, 6:30-7:30 p.m at REI.
BIG TIMBER
1-hr Avalanche Awareness Lecture. Tuesday, January 10, 7-8 p.m at Big Timber High School.
HELENA
1-hr Avalanche Awareness Lecture. Thursday, January 12, 6:30-8:30 p.m at Exploration Works.
CODY, WYOMING
Snowmobiler Introduction to Avalanches with Field Course. Lectures on Saturday, January 14 at Mountain Valley Motorsports with an all day field session near Cooke City on Sunday, January 15. Advanced registration IS REQUIRED.