Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Forecast on Monday, February 3rd at 7:00 a.m. Today’s forecast is sponsored by Grizzly Outfitters and Highline Partners. This forecast does not apply to operating ski areas.
Snow started yesterday morning and dropped 14” in the Bridger Range and 7-10” elsewhere. Overnight, wind shifted east-northeast at 5-15 mph with gusts of 20-30 mph. In the Bridger Range east wind is 15-25 mph with gusts to 50 mph. This morning temperatures are single digits to low teens F and today will reach mid-teens F. Wind will remain 15-30 mph out of the east-northeast and decrease to 5-15 mph this afternoon. Snow showers taper with a couple more inches this morning followed by partly sunny skies this afternoon.
Since yesterday morning the Bridger Range received 14” of snow equal to 1.4” of snow water equivalent (SWE). Strong east wind drifted snow into thicker slabs that are easy to trigger. These slabs formed in less common locations, like along west facing ridgelines or upslope of rolling terrain on east aspects. Today avoid wind loaded slopes where natural avalanches are possible and human triggered avalanches are likely.
Yesterday Doug skied in the northern Bridger Range and didn’t see signs of instability in the new snow, but skied conservative terrain due to the rapid, heavy load (video). He is tired of talking about sugary snow at the ground, but continues to remind us it makes larger avalanches possible. Remain diligent and avoid slopes where this weak layer is suspect.
On Mt. Ellis weak sugary snow makes up most of the shallow snowpack (video, photo). The northern Gallatin Range received about half as much snow as the Bridgers (9”=0.6” SWE) and in Hyalite avalanches are not as likely, but still possible. However, on Mt. Ellis the weak snowpack makes larger avalanches likely where new snow is drifted into thicker slabs. Today avalanche danger is CONSIDERABLE on wind loaded slopes and MODERATE on other slopes.
Near Big Sky, West Yellowstone and Cooke City the mountains received 7-10” of snow equal to 0.4-0.8” of SWE. Avalanches are possible to trigger, especially where east wind grew fresh wind slabs. On non-wind loaded steep slopes dry loose avalanches and slabs of new snow are possible to trigger. On Thursday near Cooke City I triggered a fresh wind slab, similar to what is possible today (details and media). Watch for cracking of the snow surface around your skis as a sign new snow or drifts are unstable.
A less likely, but higher consequence avalanche can break deeper and wider on sugary weak layers near the base of the snowpack (photo). Ian discusses this problem in his recent video from Lionhead. Dave was in Cooke City over the weekend and found unstable test results on this layer, and his video shows the thick, heavy slab that could break. On Saturday near Big Sky a cornice fall triggered a deep avalanche (details and photo), and in the southern Madison Range a snowmobiler triggered a deep and wide avalanche, and luckily was not caught (details and photo).
Be extra cautious of wind loaded slopes, and carefully evaluate the snowpack and terrain before riding any steep slope. Avalanches are possible to trigger and the avalanche danger is rated MODERATE.
If you get out, please send us your observations no matter how brief. You can fill out an observation form, email us (mtavalanche@gmail.com), leave a VM at 406-587-6984, or Instagram (#gnfacobs).
Thank You, King and Queen of the Ridge Hikers!
Thanks to the 52 hikers and 9 Teams who rallied their supporters and fundraised for the event. "Strange Cattle of Map Brewing" raised the most money and Mountain Project hiked the most. New Age Artisans and Highline Partners rallied together for the second most hikes. The entire board of the Friends of the Avalanche Center and the avalanche forecasters thank you!
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out and plan to attend one or two: Events and Education Calendar.
COOKE CITY
Every Friday and Saturday, Snowpack Update and Rescue Training. Friday, 6:30-7:30 p.m. at the Soda Butte Lodge. Saturday anytime between 10-2 @ Round Lake.
BOZEMAN
February 4, Sidecountry Avalanche Awareness. 6-7 p.m. at the Story Mill Community Center.
February 5, Women’s Specific Avalanche Awareness. 6-7 p.m. at REI.
February 7, Companion Rescue Clinic, 6 - 8 pm at REI followed by a field day February 8. More info and Register Here.
February 10, 1-hr Avalanche Awareness. 5:30 p.m. at Gallatin Valley YMCA.
WEST YELLOWSTONE
February 8, 1-hr Avalanche Awareness, 7-8 p.m. at West Yellowstone Holiday Inn.
See our mid-season snowpack summary for a review of the deep slab avalanche problem and general (conservative) travel advice.