Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, March 14, at 7:00 AM. Today’s advisory is sponsored by Spark 1 and Alpine Orthopedics. This advisory does not apply to operating ski areas.
Over the past 24 hours the mountain around West Yellowstone including the southern Madison Range picked up 8-12 inches of new snow. Cooke City picked up 6-8 inches while the mountains around Bozeman and Big Sky received 3-5 inches. At 5 a.m. it’s still snowing and temperatures are in the 20s F. Winds are blowing 15-30 mph out of W-SW with gusts up to 40 mph. Today, snow will continue and another 1-3 inches is expected by this afternoon. Snow tapers off later in the day and skies will become partly to mostly cloudy. Temps will warm into the upper 20s to low 30s F and winds will continue to blow 15-30 mph out of the W-SW. There will be a break in the weather tonight, but another round of moisture is forecasted to impact the area tomorrow into Wednesday.
Southern Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone
The mountains near West Yellowstone have been favored by this latest storm. Since yesterday morning Carrot Basin Snotel site in the southern Madison Range has received up to a foot of snow totaling 1.2 inches of SWE. Madison Plateau Snotel site is recording .9 inches of SWE. This new snow has been accompanied by strong west-southwest winds which will create unstable and dangerous avalanche conditions.
Yesterday, my partner and I rode in the Taylor Fork and triggered numerous small avalanches with only a few inches of new snow (video, photo). Conditions will be even more unstable today and I expect natural avalanches to occur on wind loaded slopes. If naturals are occurring, it’s very likely that human triggered avalanches will occur as well.
Given the heavy amount of new snow, slopes will not need to be wind loaded to produce avalanches. Weak interfaces within the storm snow along with weak layers buried deeper in the pack both hold the potential to produce natural and human triggered slides.
Today, very dangerous avalanche conditions exist on wind loaded slopes which have a HIGH avalanche danger. Non-wind loaded slopes have a CONSIDERABLE avalanche danger.
Cooke City
Surprisingly, the mountains around Cooke City did not get hit quite as hard. Fisher Creek Snotel site is recording .5 inches of SWE in the past 24 hours. This storm is producing strong winds - Lulu Pass weather station is showing a gust of 50 mph this morning. Today, wind slabs will be the primary avalanche concern. Evaluate snowpack and terrain carefully and avoid all slopes with wind deposited snow. There are a few weak interfaces buried 1-3 feet deep that make human triggered avalanches possible on non-wind loaded slopes. It’s worth digging down to assess these layers before committing to steeper terrain.
Today, 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 Northern Madison Range
Northern Gallatin Range
This storm was a bit of a bust for the northern ranges – so I thought. When I arrived at the office at 4 a.m. both Big Sky and Bridger Bowl were only reporting a few inches of new snow. Since I sat down the storm has kicked in and both areas have picked up an additional 2-3 inches. As the storm rages on, wind slabs are growing by the minute. Today, I expect slopes with wind deposited snow to be sensitive to human triggers. Storm slabs and lose snow avalanches in steep terrain will also be a growing concern. Outside of new snow instabilities the snowpack is mostly stable.
Today, human triggered avalanches are likely on wind loaded slopes which have a CONSIDERABLE avalanche danger. Non-wind loaded slopes have a MODERATE avalanche danger.
Doug 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.
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