Good Morning. This is Doug Chabot with early season snowpack information issued at 7:30 a.m. on Wednesday, December 2. Today’s information is sponsored by Yellowstone Arctic Yamaha in partnership with the Friends of the Avalanche Center. This information will be updated late Friday.
High pressure, sunny skies and cold temperatures have dominated our weather. Strong east winds blew through the weekend before changing westerly where they are currently averaging 15 mph with gusts to 25 mph. Temperatures are in the single digits to teens in the mornings and warming into the 20s during the day. This will continue for the next few days with some clouds rolling through, but in general the weather is uneventful for the immediate future: seasonal temperatures, moderate westerly winds and no snow forecasted until the middle of next week.
There has been no snow or avalanche activity since Thanksgiving. East winds created a few slabs near the ridgetops, but these are not an avalanche issue any more. The mountains have 1 ½ to 3 feet of snow on the ground. Regardless of depth, cold temperatures are weakening the snowpack (video explaining this process). Thin snow cover and cold temperatures create sugary facets which can grow into large, crumbly depth hoar crystals. The sun is low, the temperatures are cold, the snow is thin and conditions are ripe for facet growth. My partner and I skied into Lionhead outside West Yellowstone on Sunday and found the entire 45 cm deep snowpack made up of facets (video, snowpit).
No matter the mountain range, the cold, clear, snowless weather is weakening the snowpack. The sugary facets are not a strong foundation and I anticipate avalanches when we finally get a snowstorm dropping more than a few inches.
Alex will issue the next information bulletin late Friday for this weekend. We will begin issuing daily advisories and danger ratings once we get more snow. In the meantime, we need your field observations so please drop us a line at mtavalanche@gmail.com.
EVENTS and AVALANCHE EDUCATION
A complete calendar of classes can be found HERE.
TONIGHT Bozeman: MSU - Introduction to Avalanches with Field Course
December 2, 3 and 5 or 6, 2015: https://www.ticketriver.com/event/16858
Workshops are held on Wednesday and Thursday evenings, with a field course on Saturday. Different topics are presented each evening. Topics include: avalanche terrain recognition, the affect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures.
Butte: December 6, Sunday, Avalanche Awareness for Snowmobilers, Redline Sports, 12-1 p.m.
Billings: December 8, Tuesday, Avalanche Awareness, MSU, 6-7 p.m.
Great Falls: December 9, Wednesday, Avalanche Awareness, Back Alley Pub, 6-7 p.m.
Bozeman: December 9, Wednesday, Avalanche Awareness, REI, 6-7:30 p.m.
Helena: December 10, Thursday, Avalanche Awareness, The Basecamp, 6-7:30 p.m.
West Yellowstone: Snowmobiler Introduction to Avalanches with Field Course
December 17 and 18, 2015: https /www.ticketriver.com/event/17356
Five hours of lectures are followed by a full day field course. Topics include: avalanche terrain recognition, the affect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures.