1 p.m.
This morning proved difficult to get accurate snowfall totals in some areas since SNOTEL and some weather stations were not updating. Here are the totals:
Bridgers: 6"snow, .5" SWE
Hyalite: 4" snow, .2" SWE
Yellowstone Club: 8.5" snow, .44" SWE
Cooke City: 3" snow, .2" SWE
Carrot Basin: 3", .3" SWE
Lionhead: 3", .2 SWE
Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Saturday, December 5, at 9 a.m. Today’s advisory is sponsored by Mystery Ranch in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
Late last night the mountains picked up 6-9 inches of snow. Winds blew westerly at 10-20 mph with gusts of 25 mph. The storm was fast moving and skies cleared pre-dawn. Today will mostly clear with partly cloudy skies tonight. Temperatures will warm from the teens this morning into the upper 20s this afternoon with southwest to west winds blowing 10-20 mph.
Bridger Range Gallatin Range Madison Range
Lionhead area near West Yellowstone Cooke City
The storm dropped .5-.6 inches of snow water which equated to 6-9 inches of powder. The snowpack is thin and measuring 18-30 inches deep and consists of at least a few layers of facets. In the Lionhead area around West Yellowstone I found the entire snowpack to be sugary, faceted snow, likely the worst in our forecast area (video). Around Big Sky, Bozeman and Cooke City the facets are sandwiched in between a few layers, but are weak and will strain to support this new load. Skiers in the southern Gallatin yesterday triggered a small wind pocket on a low angled slope (photo). It was very windy yesterday and plenty of snow moved around loading slopes. Eric was at the Yellowstone Club and made a video of the wind-loading. Last night’s storm came in with winds too. Are you noticing a theme here? Wind slabs are sitting on weak, faceted snow and will avalanche. At the first sign of cracking or collapsing you should go elsewhere. These are red flags that the snow is unstable.
For today, the avalanche danger is rated CONSIDERABLE since it’s likely you could trigger an avalanche, especially on wind-loaded slopes.
Eric will issue the next advisory tomorrow morning at 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.
EVENTS and AVALANCHE EDUCATION
A complete calendar of classes can be found HERE.
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.
Bozeman: December 15, Tuesday, Avalanche Awareness and Beacon 101, Beall Park, 6-8 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.