This is Ian Hoyer with the avalanche forecast for Friday, January 10th, at 7:00 a.m. sponsored by Polaris and Cooke City Super 8/Bearclaw Bob’s. This forecast does not apply to operating ski areas.
A dusting of snow fell yesterday morning as snowfall tapered off and skies cleared, but there were not significant accumulations. Overnight, winds picked up around Bozeman and Big Sky, now blowing 20-30 mph out of the west, with gusts of 40-45 mph. Winds elsewhere are a bit lighter (10-15 mph) out of the northwest and north. Temperatures are in the teens F this morning (single digits F around Cooke City).
Today, winds will continue to be strongest in the northern ranges, perhaps picking up a bit everywhere as snowfall begins late this afternoon. High temperatures will be in the 20s and 30s F.
Snowfall tonight will add up to 3-6” by tomorrow morning across most areas, with snowfall continuing tomorrow. Island Park will get a bit less, with 1-3” expected.
Deep avalanches, breaking on weak layers near the ground, continue to be triggered in the mountains around Cooke City. Yesterday afternoon, a 6 ft deep slide was triggered on Mt. Abundance either by snowmobilers from 1000 ft away or by snow falling off a tree (video). Either way, this is a good indication that conditions remain touchy. Another recent slide (that may also have broken yesterday) of similar depth was also seen on the east side of Henderson Mtn. (photo). With Persistent Slab avalanches being likely to trigger today, conditions remain dangerous and our recommendation is to continue to avoid travelling on or beneath slopes steeper than 30 degrees. The avalanche danger is CONSIDERABLE.
Winds picked up overnight in the mountains around Bozeman and Big Sky. With plenty of soft snow to blow around, new wind drifts will form and Wind Slab avalanches will be easily triggered today. There may also be some wind drifts that formed on Wednesday that haven’t bonded yet. These slides could break 1-3 ft deep and be large enough to bury you or sweep you into rocks or trees.
Persistent Slab avalanches breaking deeper in the snowpack are a secondary, but still very real concern. As Mark explains in his video from yesterday near Mt. Blackmore, you’re most likely to trigger one of these slides from thinner snowpack areas. It could then propagate out into the deep areas, making for quite large avalanches.
Today, avoid freshly wind-loaded slopes where the avalanche danger is CONSIDERABLE. Carefully evaluate the potential consequences of triggering a slide before riding all other steep slopes, which have a MODERATE avalanche danger.
Around Island Park and West Yellowstone, triggering Persistent Slab avalanches on weak layers low in the snowpack is still possible, but with little recent snowfall it has become somewhat less likely (Island Park video). Thinner areas are where you’re most likely to trigger one of these slides. If you’re going to start poking into avalanche terrain, start out with smaller slopes with mellower slope angles that have few obstacles beneath them, to further minimize both the likelihood and consequences of triggering a slide.
There may also be pockets where you could trigger Wind Slab avalanches, so it’s worth keeping your eyes out for signs of wind loading as well.
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
Avalanche Fundamentals with Field Session for non-motorized travelers THIS WEEKEND. Sign up ASAP or sign up for one on the last weekend of January.
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.
On Tuesday, a skier was killed in an avalanche in Colorado (initial report from CAIC). On Sunday a skier was killed, and a second sustained injuries in an avalanche in western Wyoming (preliminary information from BTAC). Our hearts go out to the skiers’ friends and family, backcountry partners, and the rescue teams.
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.