GNFAC Avalanche Forecast for Wed Nov 25, 2015

Not the Current Forecast

Good Morning. This is Alex Marienthal with early season snowpack information issued at 7:30 a.m. on Wednesday, November 25th. Today’s information is sponsored by Bridger Bowl in partnership with the Friends of the Avalanche Center. This information will be updated tomorrow morning.

Mountain Weather

The Bridger Range and Hyalite have 3 inches of new snow this morning while other areas have 1-2 inches. Winds have been 10-20 mph out of the east. Temperatures are in the single digits F and will remain cold through today and drop below zero tonight. Today, I expect 1-2 more inches of snow in the Bridger Range and 3-5 inches in other areas. Winds will remain out of the east around 20 mph with gusts exceeding 30 mph through Friday, and temperatures will be in the single digits and teens F.

Snowpack and Avalanche Discussion

Snowfall will continue today in all areas. Easterly winds will transport the new snow and create slabs on west facing slopes. East winds are rare and can create unusual patterns of instability. Look for slabs in uncommon locations such as the west aspect of ridgelines and at mid elevations.

Yesterday, Doug and I toured north of Bridger Bowl and found variable stability. We found weak faceted snow, but unstable conditions were not widespread (video). A skier found similar patterns of stability in the northern Madison Range on Monday (photo). Look for unstable snow where windblown snow has formed a dense slab above a weak layer (photo).

Weak faceted snow has been found in the Bridger Range, Hyalite, and the northern Madison Range. Similar conditions likely exist in the southern Madison and southern Gallatin ranges. Eric went to Beehive yesterday and found a shallow snowpack full of very weak sugary facets (video). The new snow is low density and has totaled .1 inches of snow water equivalent (SWE), which is not enough to decrease stability. However, more snow and wind could make avalanches possible in areas that have this weak layer of facets.

Initial reports from Cooke City are showing a relatively strong three foot deep snowpack. The season is early and we have limited snowpack data. This is a good time to be conservative and not take chances. Avalanche danger will increase in areas that receive more snow today. Look for recent avalanches and collapsing or cracking. These are obvious signs that the snow is unstable. If signs of instability are not obvious, take a few minutes to dig and look for buried weak layers. Treat avalanche terrain the same all winter. Carry rescue gear, travel with a partner, and travel one at a time in avalanche terrain. Have a safe and happy thanksgiving.

Doug will issue an advisory tomorrow morning. We will begin issuing danger ratings as we get more snowpack data. We need your observations, so please drop us a line at mtavalanche@gmail.com if you get out.

AVALANCHE EDUCATION

A complete calendar of classes can be found HERE.

MSU - Introduction to Avalanches with Field Course

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.

December 2, 3 and 5 or 6, 2015: https://www.ticketriver.com/event/16858

West Yellowstone: Snowmobiler Introduction to Avalanches with Field Course

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.

December 17 and 18, 2015: https /www.ticketriver.com/event/17356

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