This is Dave Zinn with the avalanche forecast for Monday, March 10th, at 7:00 a.m. sponsored by Uphill Pursuits and Klim. This forecast does not apply to operating ski areas.
This morning, temperatures are in the 20s to low-30s F, with 15-40 mph winds from the west and southwest. There is no new snow.
Today, temperatures will be in the 30s to low-40s F, with 15-40 mph winds from the west and southwest and increasing clouds throughout the day. There is a chance for a trace of new snow later today, but the next significant snowstorm moves into the area on Wednesday afternoon.
In the Lionhead area and the Southern Gallatin and Southern Madison Ranges, smaller avalanches on slopes with recent drifts of wind-loaded snow and larger avalanches breaking on buried weak layers are possible.
The primary concern is persistent slab avalanches breaking 2-3’ deep on weak layers formed in late January. The last avalanches failing on these weak layers occurred over a week ago and triggering one has become less likely. These slides mostly failed on treed, mid-elevation slopes, leading to several burials and close calls (Lionhead, Cabin Creek, Tepee Basin). Yesterday, Alex rode through the Lionhead area and described in his video why the snowpack structure remains a concern.
Wind slab avalanches will be smaller, generally breaking less than a foot deep, and suspect terrain at upper elevations and below cornices is identifiable. Avoid these specific areas or watch for indicators of instability, such as shooting cracks.
Carry and train with rescue equipment and ensure only one person at a time is exposed to terrain steeper than 30 degrees. Consider the potential outcomes of an avalanche on a given slope and avoid those with higher consequence features such as trees, cliffs and gullies. The danger is rated MODERATE
The snowpack is generally stable in the mountains around Bozeman, Big Sky, Cooke City and Island Park. Small avalanches are possible on slopes with isolated instability related to recently wind-drifted snow. Cooler temperatures and cloud cover will limit wet loose avalanches.
Yesterday, I toured Hyalite Canyon and assessed for wind slab instability by digging extended column tests and watching for shooting cracks. I found that wind drifts have generally stabilized (observation). The primary concern resides in the isolated areas where they have not bonded. Two days ago, skiers in the Bridger Range triggered wind slabs 8-10” deep and 10-20’ wide, with one person caught and carried ten feet (details and photos).
Some people are choosing to ski and ride in very steep and technical terrain. While this is a reasonable time to consider more committing objectives, the margin for error is razor-thin in these spaces, with slight miscalculations (avalanches) having significant consequences. Assess the snowpack for isolated instability in this terrain and back off if conditions don’t feel right (video).
While most slopes are stable, the fundamentals of safe travel in avalanche terrain always apply–beacon, shovel, probe and one at a time on steep slopes. The avalanche danger is LOW.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
Avalanche awareness focused on springtime avalanche conditions: Thursday, March 13 at the Bozeman REI from 6-7:30 p.m. The event is free but has limited space and requires registration HERE.