This is Ian Hoyer with the avalanche forecast for Friday, January 17th, at 7:00 a.m. sponsored by Highline Partners and Gallatin County Sheriff Search and Rescue. This forecast does not apply to operating ski areas.
There is a trace to an inch of new snow and it’s snowing lightly this morning. Winds blew 25-35 mph, gusting to 50-60 mph, out of the west around Bozeman and Big Sky yesterday, backing off a little overnight. Winds are 10-20 mph with gusts to 30 mph around West Yellowstone, Island Park and Cooke City. Winds today will be moderate, shifting to the northwest.
Temperatures are in the teens and 20s F this morning. Temperatures today will only rise a few degrees before they begin to fall as a cold front moves through the area.
Light snowfall will continue today and tonight, with 1-3” accumulating by tomorrow morning.
Temperatures will be frigid through the long weekend, with high temperatures in the single digits above or below 0 F.
You could still trigger a Persistent Slab avalanche on weak layers 1-2 ft off the ground. As we get further out from the end of the last loading event, the likelihood of triggering a slide is going down. Still, it’s worth remaining alert, because if you do trigger one of these slides it’ll take out most of the season’s snowpack and be big and destructive. A recent, large, natural avalanche on Red Mountain in the southern Madison Range, is a good example of the sort of big slide you could still trigger. You’re most likely to trigger one of these slides from a thinner area, whether that’s a lower elevation slope, a thin spot near rocks, or somewhere in the zones around West Yellowstone that generally have a thinner snowpack.
Assessing the likelihood of triggering one of these slides on any given slope is difficult, so your most reasonable options are either to continue avoiding slopes steeper than 30 degrees or to go into avalanche terrain and accept that there is some residual risk of triggering a big slide. If you are getting into avalanche terrain, ride one at a time while your partners wait in a safe spot and make sure everyone in the group has avalanche rescue gear so you are in a good position to respond if you do end up triggering a slide.
Human triggered avalanches are possible and the avalanche danger is MODERATE today.
Wind slab avalanches are the primary concern near Bozeman and Big Sky. Yesterday, skiers on Mt. Blackmore observed a fresh slide on the north face with a 1-2 ft deep crown that was already filling back in (observation). Plumes of snow were visibly drifting off the high peaks in the Bridger, N. Madison and N. Gallatin ranges. Winds have also been blowing at lower elevations, so stay on alert for drifting and cross-loaded gullies down low as well.
New snow falling today will provide more fuel for ongoing wind loading and could also mask signs of loading from previous days. Keep your eyes out for both new and old wind drifts and either avoid them or assess how well they’re bonded before getting onto a steep slope.
Persistent slab avalanches have become mostly unlikely in many areas where the snowpack has gotten deeper, but they are a lingering concern in places with shallower snow (see Mark’s video from Beehive for a good example).
The avalanche danger is MODERATE.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
January 21, 6-7:30 p.m., Women and Girls Avalanche Awareness + Beacon Drills. Story Mill Community Center.
January 23, 6-8 p.m. & January 25, 10 a.m.-2 p.m., Women’s Companion Rescue w/ Sisters of Snow. Required pre-registration and more information HERE.
January 25 or 26, 9 a.m.-3 p.m. Avalanche Fundamentals Field Course. Required pre-registration and more information HERE.
Every weekend in Cooke City: Friday at The Antlers at 7 p.m., Free Avalanche Awareness and Current Conditions talk, and Saturday from 10 a.m.-2 p.m. at Round Lake Warming Hut, Free Rescue Practice.
Thank you for sharing observations. Please let us know about avalanches, weather or signs of instability via the form on our website, or you can email us at mtavalanche@gmail.com, or call the office phone at 406-587-6984.