Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Forecast on Wednesday, February 15th at 6:45 a.m. This information is sponsored by Bridger Bowl, Cooke City Motorsports and Werner Wealth Management (Advisors with DA Davidson). This forecast does not apply to operating ski areas.
Before shutting down yesterday, the snowstorm dropped 3” in the Bridgers, 11” in Hyalite, 5” around Big Sky, 8” in Taylor Fork and an inch in West Yellowstone and Cooke City. Wind is blowing north to west at 10-20 mph with gusts of 30 mph, and mountain temperatures are zero to minus 8F. Today will be sunny, winds will lessen to 5-15 mph (N-W) and temperatures will climb into the teens. No new snow is expected until early Sunday morning.
What a storm. Snowfall totals were 9” in the Bridger Range, 18” in Hyalite, 12” around Big Sky, and 14” in Taylor Fork. The snow measured .6-1” of snow water equivalent, which means it was mostly 6-8% powder. Avalanches were widespread throughout the Bridger, Gallatin and Madison Ranges and involved only new snow. We have not heard of deeper layers in the snowpack breaking, which is welcome news.
The ski patrols were on the front lines fighting avalanches, a whumpf was felt in Lick Creek in Hyalite, and small natural slides were seen on History Rock, in Flanders and Sourdough Creek, and a skier triggered a small slide in Beehive Basin. Our observations page has details and pictures of this activity. Ian and I skied into Mt. Ellis and dug a snowpit on the ridge. We found 12-14’” of new snow that easily propagated in our stability test (ECTP2). With all the new snow we planned on staying out of avalanche terrain and this test result confirmed our assumption that triggering slides would be likely (video). It has been less than 24 hours since the storm ended and slopes need time to adjust. Wind is loading a few slopes near the ridgelines and I expect folks will trigger avalanches. Most will involve the new snow, but a deeper slide could break too. I sank to the ground in weak, faceted snow, a blaring sign that some slopes have a thin and weak structure (photo). Our to-do list is simple: measure slope angles and stay out of avalanche terrain.
For today, the avalanche danger is rated CONSIDERABLE on all slopes.
The mountains around West Yellowstone and Cooke City received 5” of new snow in the last 36 hours. The snowpack can handle this load and I do not expect natural avalanche activity. Wind is blowing north to northeast at 5-15 mph, and gusting to 30 mph in Lionhead. Wind slabs will grow with 5” of new snow. In the top 3 feet of the snowpack are a few weak layers that have not been a widespread problem, but they avalanched a week ago (Island Park video) in isolated areas. With new snow, wind and a few areas of lingering weak snow, it’s a good idea to dig and make sure a slope is stable before getting into avalanche terrain, especially slopes above terrain traps.
With 9” of fresh snow, slabs of new and wind-drifted snow will be sensitive to human triggers. Wind is blowing and drifts will grow thicker even as snowfall tapers off (Island Park video). Buried weak layers in the upper three feet of the snowpack could result in avalanches breaking deep and wide. Our to-do list is simple: measure slope angles and stay out of avalanche terrain.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
February 16, FREE Avalanche Awareness night for women at REI Bozeman. Time TBD.
February 19, 10 a.m.-2p.m. Companion Rescue Clinic Field Day in the Bozeman area. Required Online Classroom Session at 6 p.m. on Feb 18. Information and course registration are HERE.
March 3-5, Bozeman Splitfest. More info and register here.
Every Saturday, 10 a.m. - 2:00 p.m. Avalanche Rescue Training, drop in for any amount of time. Round Lake Warming Hut, Cooke City. Free.
Loss in the Outdoors, is a support group for those who have been affected by grief and loss related to outdoor pursuits. Check out the link for more information.
Bruce Jamieson’s videos on Snow Science explain heady topics to the layman. Understanding the avalanche dragon helps keep us alive.