Good morning. This is Dave Zinn with the Gallatin National Forest Avalanche Forecast on Monday, January 23rd at 7:00 a.m. Today’s forecast is sponsored by Yellowstone Ski Tours, the Community Food Co-op and Werner Wealth Management (Advisors with DA Davidson). This forecast does not apply to operating ski areas.
The Bridger Range received 4” of new snow, with 2” near Big Sky and nothing elsewhere. This morning, temperatures are in the single digits to low teens F with 5-15 mph winds from the northwest to northeast. Today, temperatures will be around 20 degrees F with 5-20 mph winds from the west to southwest. The mountains near Bozeman will receive 1-2” of new snow by morning, with a trace to 1” elsewhere. Snowfall will continue tomorrow, favoring the mountains around Bozeman.
In the mountains near Big Sky, West Yellowstone and Cooke City, human-triggered avalanches breaking 1-2 feet deep on a weak stripe of buried surface hoar and within the recently wind-drifted snow are possible. Two days ago, a skier triggered a slide outside the boundary of Big Sky Resort that broke 8-12” deep on a wind-drifted slope (details and photo). Turn back if you observe signs of recent wind-loading such as a hard, hollow-feeling snow surface, see lenses of drifted snow or signs of instability, such as shooting cracks or collapsing.
Making accurate assessment challenging, a persistent weak layer of surface hoar buried 1-2 feet deep is not on all slopes and is not yielding unstable results in all tests. Yet, it can result in avalanches (Cooke City video, Lionhead video). A skier triggered an avalanche on this layer near Cooke on Saturday (details). In the past week, riders triggered slides breaking on the surface hoar layer at Two top and Lionhead, and avalanches failed naturally at Buck Ridge and near Cooke City.
Today, avoid recently wind-drifted slopes where the two avalanche concerns overlap. Assess and test the upper several feet of the snowpack for instability related to surface hoar or, keep it simple by avoiding slopes steeper than 30 degrees (Hebgen Lake video). Avalanches breaking deeper in the snowpack are unlikely but triggering weak snow near the ground from shallow spots in the snowpack is a lingering possibility.
The danger is rated MODERATE.
In the mountains around Bozeman, triggering an avalanche that breaks on recently wind-drifted slopes is possible. On Saturday, Alex and Ian found a hard slab of drifted snow sitting on weaker snow on Saddle Peak, south of Bridger Bowl (video). Yesterday, similar drifts concerned my partner and me north of Bridger Bowl near the Playground (video). Avoid rounded deposits of drifted snow where triggering a slide is most likely, and use added caution in terrain where features like trees, rocks and cliffs increase the consequences of getting caught in an avalanche.
The deeper snowpack is weak, but slides breaking on these deeper layers are unlikely without additional snowfall. However, digging to test these layers is prudent. Yesterday, in our snowpit, they failed and propagated, the two ingredients needed for an avalanche (video).
Today the avalanche danger is MODERATE on wind-loaded slopes and LOW on non-wind-loaded slopes.
Please share avalanche, snowpack or weather observations via our website, email (email@example.com), phone (406-587-6984), or Instagram (#gnfacobs).
In Island Park, human-triggered avalanches breaking 1-2 feet deep on a weak stripe of buried surface hoar and within recently wind-drifted snow are possible. Avoid wind-drifted slopes where the two avalanche concerns overlap. Assess and test the upper several feet of the snowpack for instability related to surface hoar, remembering that this can be tricky due to the spotty nature of its distribution. The simple solution is to avoid slopes steeper than 30 degrees.
Follow safe travel protocols and carry an avalanche beacon, shovel and probe during every trip to the backcountry.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
January 26, 6-7 p.m., FREE Avalanche Awareness in Cody, WY. Information HERE.
January 27, 6:30 p.m., DILLON Avalanche Fundamentals. Information and course registration HERE.
February 3, 9 a.m.-3 p.m., LIVINGSTON Avalanche Fundamentals. Information and course registration HERE.
February 9, FREE Avalanche Awareness at REI Bozeman.
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.
KING AND QUEEN OF THE RIDGE, FEBRUARY 4TH
Do you like to hike? Do you like to ski? Then the King & Queen of the Ridge is for you. Hike, ski and raise money for the Friends of the Avalanche Center in their 2nd biggest fundraiser of the year. Join the effort to promote and support avalanche safety and awareness! Fundraising prizes for the top 5 individuals who raise over $500. No racing is necessary to compete for the fundraising prizes. Info is HERE. Race participants for the February 4th event must register separately with Bridger Bowl HERE.
Full accident reports have been released for most of this season’s avalanche fatalities. Take a few minutes to read back through them and see what lessons you can learn from these tragic accidents (accident report archive).