Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Saturday, March 7, at 7:30 a.m. Mystery Ranch in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas.
Mountain temperatures this morning were in the mid-20s F with westerly winds blowing 10-20 mph. Today should have some clouds, temperatures rising into the 30s and 40s F, and winds continuing 10-20 mph.
Bridger Range Madison Range Gallatin Range
Lionhead Area near West Yellowstone Cooke City
While the big problem is a lack of fresh powder, the main avalanche problem is wind slabs up to a foot thick resting on small, weak facets. During these dry and mostly stable conditions, I tend to park my sled and ski steep lines in the alpine, but this is exactly the terrain where wind slabs will be a problem. Yesterday in the northern Madison Range my partner and I found several skier triggered wind slabs (photo1, photo2) and one naturally triggered one. A large one was triggered on Lone Mountain on Wednesday (photo), one was triggered on Thursday in the northern Gallatin Range (photo), and several were triggered by skiers near Cooke City during the last few days (photo).
Debris from these avalanches has been 1-3 feet deep and the main danger of these slides is being injured if they push you into trees or rocks or knock you off your sled. The other issue with these wind slabs is that many of them rest on weak, faceted snow like Doug found early this week near West Yellowstone (video). Facets will keep these wind slabs unstable for longer than normal.
Most slopes have stable snow, and these wind slabs have a spotty distribution but you need to be looking for them especially if riding in steep exposed terrain. Their location depends on localized wind patterns and less on aspect. Despite the recent avalanche activity, I’m rating the avalanche danger LOW based on the travel advice in the Avalanche Danger Scale because conditions are generally safe and stable.
Believe it or not, the snowpack is near average for water content even though low elevation snow is very thin or non-existent. Check out this image of Montana drainage basins or get the full report from the NRCS.
Eric will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
AVALANCHE EDUCATION and EVENTS
1-hour Avalanche Awareness, Bozeman, REI, 6:30 - 8 p.m., Wednesday, March 11.