Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Advisory issued on Sunday, December 10th at 6:45 a.m. Today’s advisory is sponsored by Cooke City Super 8/Bearclaw Bob’s and Bridger Bowl. This advisory does not apply to operating ski areas.
This morning, temperatures are high 20s to low 30s F in the mountains and 5-10 degrees colder in the valleys. Wind is west-northwest at 15-25 mph with gusts near Bozeman and Big Sky up to 35 mph. Today, temperatures will reach the high 30s to low 40s F, and wind will be west-northwest at 15-25 mph near Bozeman and 5-15 mph elsewhere. A strong ridge of high pressure continues to block precipitation this week. Late this week, a shift to cooler, unsettled weather will bring a chance for snow next weekend.
Strong cross-slope winds last week, and strong downslope winds prior to yesterday, drifted snow into slabs in unusual locations in the Bridger Range. Wind slabs one to two feet deep are located below ridgelines and across mid-elevation terrain. Carefully assess terrain for the presence of hard, thick drifts of snow, and avoid these features today. Less wind and limited snow transport yesterday allowed these slabs to gain strength, and they will be difficult to trigger today, but remain possible. Today, avalanche danger is MODERATE on wind loaded slopes and LOW on all other slopes.
A generally stable snowpack exists, and avalanches are unlikely without recent loading from snow and wind. I found these stable conditions in Beehive on Friday (video), and Doug and Eric had similar findings in Hyalite on Thursday (video). Watch for isolated wind slabs, and assess terrain for the consequences of being caught in even a small slide.
Small wet loose avalanches were observed during the heat of the day on Friday (photo, photo), and are possible today. Sunny slopes will have a firm crust on the surface this morning, which will inhibit wet avalanche activity. If this crust softens, be cautious of small wet loose slides on sunny slopes this afternoon.
Conditions are generally stable, but it is important to continue safe travel habits. Expose no more than one person at a time to avalanche terrain. Practice clear communication and identifying safe zones. Take time to practice with your rescue gear.
Today, a generally stable snowpack without recent snow or wind-loading makes avalanche danger LOW.
If you get out and have any avalanche or snowpack observations to share, drop a line via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
Upcoming Avalanche Education and Events
BILLINGS
Dec. 12, Avalanche Awareness for Snowmobilers, 6-7:30 p.m. at Red Lion Hotel and Convention Center, Billings
BOZEMAN
Dec. 13, Avalanche Awareness, 6:30-8 p.m. at Gallatin Valley Snowmobile Association, 4-Corners
Dec. 21, Avalanche Awareness, 6-7:30 P.m. at Play It Again Sports, Bozeman
Jan. 12 and 13, Companion Rescue Clinic, Info and Register
Jan. 17, 18 and 20 or 21, Introduction to Avalanches w/ Field Day, Info and Register Here
Jan. 24, 25 and 27, Advanced Avalanche Workshop w. Field Day, Info and Register Here
Feb. 9 and 10, Companion Rescue Clinic, Info and Register
WEST YELLOWSTONE
Dec. 14 and 15, Snowmobiler Introduction to Avalanches with Field Course, Info and Register Here
COOKE CITY
15 and 16 December, Weekly Current Conditions and Avalanche Rescue, 6:30-7:30 p.m. Friday @ the Super 8, and anytime between 10-2 on Saturday @ Lulu Pass road.
Check out this 2-minute video on the snowpack. Great graphics illustrate the process of sintering and faceting. Thanks to SINTR Visual Communications!