Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Leap Year, Wednesday, February 29 at 7:30 a.m. Mystery Ranch, in partnership with the Friends of the Avalanche Center, sponsor today’s advisory. This advisory does not apply to operating ski areas.
Yesterday two inches of snow fell in the southern mountains while the northern areas got a trace to one inch. Temperatures are in the high single digits this morning with increasing southwest winds. Currently ridgetop winds are averaging 20-30 mph with gusts near 45 mph. Clouds will increase today, temperatures will not rise much and winds will continue to blow strong out of the southwest. Snowfall will start later this morning with accumulations of 2-4 inches in the southern mountains and 1-2 inches up north.
The Bridger Range, northern Madison Range, southern Gallatin Range, the Lionhead area near West Yellowstone and mountains around Cooke City:
The Bridger Range has weak snow. Most of the avalanches from Friday through Sunday released on large facets (depth hoar) near the ground. Many avalanches near Fairy and Frazier Lake (video), Saddle Peak, Wolverine Bowl (video) and others broke naturally with storm snow and also with the help of human triggers.
The mountains near Big Sky had limited natural avalanche activity, but weak snow was remotely triggered by skiers north of the ski areas this weekend. In one instance a low angled slope less than 35 degrees avalanched. Small grained facets buried 1 ½ to 2 feet under the surface is the weakest layer on most slopes in southwest Montana. We found this also to be true above Hebgen Lake on Monday when we got cracking and collapsing as we skied (video, photo). Two inches of new snow (.2” SWE) around West Yellowstone and Cooke City, coupled with strong winds loading slopes, are enough to keep the snowpack on edge.
Although avalanche activity is diminishing, the snowpack is still weak, unstable and suspect until proven otherwise. Furthermore, strong west to southwest winds are building thick wind slabs that can be easily triggered. For today, the avalanche danger is rated CONSIDERABLE on all slopes.
The northern Gallatin and southern Madison Ranges:
The northern Gallatin Range, especially in Hyalite drainage, has slightly better stability than the surrounding areas. Facets at the ground are still easy to find, yet have gotten stronger with time. The layer of small grained facets buried 1 ½ to 2 feet deep is our primary concern. The same holds true for the southern Madison Range. Mark was riding in Cabin Creek and Taylor Fork yesterday and only saw one small recent avalanche and one larger, but older slide on Skyline Ridge. His stability tests showed strengthening of the depth hoar and confirmed the presence of the smaller facets which propagated fractures (snowpit profile). Strong winds today will load slopes and add stress to this layer. Consequently, the avalanche danger is rated CONSIDERABLE on all slopes steeper than 35 degrees and MODERATE on less steep slopes.
Mark 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.
Accident Reports
The accident reports for the avalanche fatality near Cooke City on February 22 and Friday’s avalanche on Saddle Peak are available on our website.
Events/Education
FREE 1-hr Avalanche Awareness Lecture, Friday, March 2, 7-8 p.m. at the West Yellowstone Holiday Inn in the room next to the bar.
Come to Bridger Bowl on Saturday, March 17th (St. Patrick’s Day) with telemark skis, AT skis, alpine skis, snowboards, split boards, or even snow blades. The theme is Snowpocalypse based on the wildly popular Mayan 2012 apocalypse. $30 gets you into the races, a pint glass, t-shirt, a good time, a raffle ticket, and food by Cafe Fresco. Pre-register at Mystery Ranch or Grizzly Ridge March 11-16. Visit http://pinheadclassic.com/ or the Pinhead Facebook page for more info.