Good morning. This is Doug Chabot with early season snowpack information issued on Sunday, November 13 at 7:30 a.m. Today’s information is sponsored by Montana Import Group in partnership with the Friends of the Avalanche Center. This information will be updated as conditions change.
A cold front pushed through yesterday morning dropping 6-7 inches of snow by noon. Last night another pulse dropped two more inches, except Cooke City which got closer to 4 inches. These snowfall amounts were measured at SNOTEL sites and ski area weather stations. Even more snow fell at higher elevations with 12” measured yesterday afternoon near Big Sky. Winds have been blowing steady and strong out of the west to northwest. They are averaging 20-30 mph with gusts exceeding 40 mph. Strong winds and scattered snow showers will continue into the middle of the week as mountain temperatures stay in the low 20s. Winter is here.
Yesterday’s snowfall fell onto a weak, faceted snowpack. On Friday, before this storm, Mark was able to trigger small wind slabs on these sugary facets on Sphinx Mountain (photo1, photo2 ). He was headed to ice climb the north face, but turned around when he determined this instability was widespread. New snow and wind since then has made the avalanche conditions even worse. Skiers in Middle Basin north of Big Sky triggered two small soft slab avalanches on sugary facets (30 feet wide, 300 feet vertical). They also found two natural slides on west facing slopes breaking on this layer. The observer wrote, “Wind tonight will create some slabbier conditions and maybe fractures will propagate even further.” Yup. And the snowpit profile he dug confirmed his field observations: weak, faceted snow underlying a slab.
Be careful venturing into avalanche terrain. Slopes with the most snow and best skiing will also be the best spots to trigger slides. Hunters need to be focused on open terrain and gullies where wind slabs likely formed overnight. Hunters and ice climbers should be especially wary of gullies and open slopes, especially exposed terrain at higher elevations where the facets are the weakest and most unstable.
If you get out in the backcountry, please drop us a line at mtavalanche@gmail.com or call us at 587-6984. Any snowpack or avalanches information is especially valuable this time of year.
Wednesday, November 16, BIG SKY
Avalanche Awareness lecture at Grizzly Outfitters, 7 p.m.
Thursday, November 17, BOZEMAN
Avalanche Awareness lecture at Northern Lights Trading Company, 7 p.m.
Thursday, November 17, BILLINGS
Avalanche Awareness lecture at the Basecamp, 6:30 p.m.
Wednesday, November 30, BOZEMAN
Introduction to Avalanches with Field Course at MSU. Wednesday and Thursday evening lectures with a field course on Saturday. More info at http://www.mtavalanche.com/education/classes/workshops