This is Eric Knoff from the Gallatin National Forest Avalanche Center with an early season Avalanche Information Bulletin issued at 3 p.m. on Monday, November 23. ProLite Gear in cooperation with the Friends of the Avalanche Center sponsor this bulletin. This information will be updated as conditions change. Uphill traffic is not allowed at Big Sky or Moonlight Basin Ski areas. Bridger Bowl has backcountry conditions since the ski area is not open.
Southwest Montana got a nice shot of winter over the weekend. A moist cold front came through in two distinct waves. The first came in Friday night into Saturday with the second showing up on Sunday morning. These two bouts of precipitation delivered a total of six to eight inches of snow in the Bridgers and the Northern Gallatins. Big Sky, Moonlight and the Yellowstone Club picked up around eight to ten inches. The Southern Madison Range and mountains around Cooke City recorded the most with ten to twelve inches. Lingering energy will continue to move through the area giving the mountains a slight chance of precipitation today and tonight. Moderate to strong winds will continue to blow along the ridge tops, but will die down this evening. A ridge of high pressure will build on Tuesday giving us dry and warm conditions through Thanksgiving.
Thanks to the new snow skiers were hitting the slopes hard this weekend with no avalanche activity reported in our advisory area. The Bridgers and northern Gallatins have a relatively stable snowpack, however some facets and surface hoar developed on and near the surface before this storm. Mark Staples found a small layer of facets on both north and south facing aspects on Sacajewea in the northern Bridgers. A skier reported surface hoar in the Hyalite area in the northern Gallatins as well. Both the surface hoar and facets are shallowly buried and will pose the greatest threat on wind loaded slopes.
Further South conditions are different. A thinner, faceted snowpack in the Madison Range and mountains around West Yellowstone and Cooke City offered a weaker foundation for this new snow to fall on. In Beehive and Bear Basin near Big Sky, a skier reported triggering loose snow avalanches on many slopes. Additionally, wind slabs will continue to grow and add stress to an already weak snowpack.
We need more snowpack data before we issue danger ratings. Our field days have been limited so we need your help. If you get out in the backcountry give us a call or send us an email with your observations. You can reach us at 587-6984 or at mtavalanche@gmail.com.
AVALANCHE EDUCATION
Basic Avalanche Awareness at MSU (12 Hour Course):
Evening Sessions: December 2 and 3, 2009, 7:00pm to 9:30pm, at MSU in Leon Johnson Hall, room 339.
Field Session: December 5, 2009, 9:15am to 3:00pm, at Bridger Bowl Ski Area.
Cost for the entire workshop is $25.00 ($5 each evening and $15 for the field session). Registration is not required for the evening sessions, but is required for the field session, which can be done at either of the evening sessions.
Basic Avalanche Awareness for Snowmobilers (12 hour Course):
Bozeman: Evening Sessions: Wed and Thursday, December 2 and 3, 2009, 7-9:30 pm; Team Bozeman
December 13 is an all day field session, exact location TBD. ($30 Donation)
No Registration Required.
One Hour Awareness:
A basic one hour awareness class will be offered at Red Line Sports in Butte, Dec 9th at 6 p.m.
A full listing of the avalanche classes offered in southwest Montana can be found on the education page of our website: http://www.mtavalanche.com/education