Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday, January 9th at 7:00 a.m. This information is sponsored by World Boards and Mystery Ranch. This forecast does not apply to operating ski areas.
The mountains near Cooke City, West Yellowstone and the southern Madison Range have 4-5” of new snow, and elsewhere there is no new snow. This morning temperatures are teens to mid-20s F and wind is southwest-west at 15-25 mph with gusts of 35-50 mph. Today temperatures will reach high 20s to low 30s F with southwest wind at 15-35 mph. Snow is expected this afternoon and tonight. By tomorrow morning there is a chance for 3-5” of new snow near Bozeman, Big Sky and Cooke City with 6-10” possible near West Yellowstone.
Southwest wind is drifting 4-5” of new snow into fresh wind slabs. These slabs can break under the weight of a person and avalanche on steep slopes, and possibly be large enough to bury or injure a person. It is also possible to trigger large or very large avalanches on weak layers buried up to 4 feet deep. In the southern mountains, the most recent avalanches of this type (that we know of) occurred last weekend in the southern Madison Range (photos/details, video) and near Cooke City, including a tragic fatal avalanche on Crown Butte (accident report, video). New snow and fresh drifts will add weight to buried weak layers and make it possible to trigger a large, potentially destructive avalanche. Be extra cautious of wind-loaded slopes, such as near cornices along ridgelines, or where you see a wind-textured snow surface or rounded, thick deposits of snow. Watch for cracks shooting across the snow around your feet, skis or snow machine as a sign fresh drifts are unstable. Avalanche danger is MODERATE.
Near Bozeman and Big Sky a person can trigger avalanches that break on weak layers buried 1-4 feet deep. On Saturday skiers in the northern Bridger Range saw a recent large natural avalanche (photo), and on Friday a very large avalanche on Saddle Peak broke 550 feet wide and almost 2 feet deep on a buried weak layer (photo of crown up close). It caught and partially buried a person who was hitting a jump in the runout zone (photos and details). No new snow with minimal wind-loading over the last few days has allowed buried weak layers to adjust and made avalanches less likely. However, if you plan to travel in avalanche terrain carefully assess the snowpack for buried weak layers and avoid steep slopes where you suspect they exist (as Dave explained in his video from the Bridger Range yesterday). Be extra cautious of wind-loaded slopes, and slopes where snow depth is variable and a large avalanche may be triggered from a relatively shallow spot. Today, human-triggered avalanches are possible and the avalanche danger is MODERATE.
Please share avalanche, snowpack or weather observations via our website, email (email@example.com), phone (406-587-6984), or Instagram (#gnfacobs).
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
Tuesday, January 10th, 6PM, Women’s Specific Avalanche Awareness + Beacon Practice at Story Mill Park in Bozeman. Free.
Thursday, Jan 12th, 6:30 PM, 1hr avalanche awareness for mechanized users at BSCO BASE in Big Sky. Free.
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.
On Saturday in Colorado, two snowmobilers were caught, buried, and killed in a large avalanche on the east face of Mount Epworth, about 6 miles east of Winter Park. Grand County Sheriff's Deputies and search and rescue were unable to locate the second rider before dark, but found the second rider deceased yesterday. (Preliminary report).