Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, November 29th at 7:00 a.m. Today’s advisory is sponsored by Yellowstone Arctic Yamaha and Yamaha Motor Corp in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
NEW THIS SEASON: Regional Conditions Pages. Links at top of advisory and in the ‘advisory’ dropdown menu.
At 4:30 a.m. snow started falling in Bozeman. By 6 a.m. 4” fell at Bridger Bowl and 2” near Big Sky. This is a fast moving storm and in the next few hours snowfall will total 3-5” accompanied by strong winds and followed by clearing, sunny skies. Temperatures are currently in the mid-teens and winds are blowing steady from the west to south at 25-40 mph with gusts of 70 at Lulu Pass outside Cooke City and mid 50s everywhere else. Today will start snowy and end sunny with wind speeds decreasing after the storm passes.
At 6 a.m. SNOTEL is down, so snowfall totals outside ski areas are unknown.
Today’s avalanche concern involves wind and new snow. Last night, gusts of 50-70 mph with strong, steady winds have loaded slopes at many elevations, not just the ridgelines. Snowfall from Monday morning and this morning will drift into wind slabs that could be triggered. Yesterday, a skier up Hyalite triggered a small avalanche 1’ deep and 25’ wide on a slope well below the ridgeline (photo). He also noted cornices growing quite large for this early in the season (photo). Cornices are a sign of wind-loading and are also triggers for avalanches when they break. Wind-loaded slopes should be approached carefully. Recent avalanches, cracking and collapsing are warning signs to stay out of avalanche terrain.
Besides new snow and wind-loading the underlying snowpack is mostly stable. We are still gathering our first field data, but all findings are similar: there is no widespread weak layer buried in the snowpack. Eric was on Saddle Peak in the Bridger Range yesterday and found stable conditions (video). I rode into Lionhead yesterday and found mostly stable snow, but got lucky in my search for instability and dug on a slope with a layer of weak snow on the ground that broke in my stability tests (video, facets photo, pit photo). I was surprised to see this. This layer was moist, only 5 cm thick and will likely not last long. However, finding it illustrates the need to dig and test even during times of stability.
This morning’s snowfall and strong winds make avalanches possible and a MODERATE avalanche danger throughout our entire advisory area.
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).
Get Avalanche Smart Video Series
The Avalanche Center and Friends group work hand-in-hand to bring you daily avalanche information and education. This last video in series of 4 shows how we create a culture of being safe in the backcountry: Get Avalanche Smart – Episode 4: The GNFAC
Upcoming Avalanche Education and Events
BOZEMAN
Nov. 29, 30 and Dec. 2, 3 or 9, Introduction to Avalanches w/ Field Day, Info and Register Here
Dec. 6, Avalanche Awareness, 6-7:30 p.m. at REI Bozeman
Dec. 7, Avalanche Awareness and Beacon Practice, 6-8 p.m. at Beall Park, Bozeman
Dec. 13, Avalanche Awareness, 6:30-8 p.m. at Gallatin Valley Snowmobile Association, 4-Corners
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
HELENA
7 December, Avalanche Awareness, 6-7:30 p.m. at Basecamp, Helena
WEST YELLOWSTONE
Dec. 14 and 15, Snowmobiler Introduction to Avalanches with Field Course, Info and Register Here
COOKE CITY
1 and 2 December, Current Conditions and Avalanche Rescue, 6:30-7:30 p.m. Friday @ the Super 8, and anytime between 10-2 on Saturday 2 Lulu Pass road.
Check out our playlist of videos from last April’s Professional Development Workshop. The topic of the day was “Avalanche Science, Avalanche Stories”.