Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Thursday, November 30th at 6:30 a.m. Today’s advisory is sponsored by Cooke City Motorsports and Buck Products 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.
Yesterday morning a few inches of snow fell in the mountains around Bozeman and Big Sky. At 5 a.m. temps are in the teens under mostly clear skies and winds are blowing 10-20 mph out of the west. Today, skies will start out mostly clear, but will become increasingly cloudy as the day progresses. Winds will continue to blow 10-20 mph out of the west and temperatures will warm into the 20s F. There is a slight chance for snow showers in the southern mountains tonight, but only light accumulations are expected. Friday looks to be another nice, sunny day.
The snowpack took multiple steps backwards during the warm weather around Thanksgiving. Since then, intermittent storms and below freezing temps have helped the snowpack recover. Since Monday, 4-8” of snow has fallen in most mountain locations. This new snow has been transported by strong westerly winds, which loaded slopes at many elevations. Today, wind loaded slopes will be primary avalanche concern.
On Tuesday, a skier up Hyalite triggered a small avalanche 1’ deep and 25’ wide on a slope well below the ridgeline (photo). He also noted large cornices, which are clear indicators of wind loading (photo). A skier outside of Cooke City also triggered a small wind slab yesterday in high alpine terrain (photo). Winds have dropped over the past 24 hours, but recently formed wind slabs could still be triggered by skiers or riders. It’s important to remember that even small slides can be dangerous, especially in steep high consequence terrain.
Besides new snow and wind-loading the underlying snowpack is mostly stable. On Tuesday my partners and I skied Saddle Peak in the Bridger Range and found mostly stable conditions (video). Our biggest concern was wind slabs along the ridgeline. Doug rode into Lionhead on the same day and found similar conditions, with the exception of one pit that produced unstable results on a layer or facets near the ground (video, facets photo). This layer is not widespread and shouldn’t last long. However, finding it illustrates the need to dig and test even when the snowpack is generally stable.
Today, human triggered avalanches are possible on wind loaded slopes which have a MODERATE avalanche danger. Non-wind loaded slopes have a LOW avalanched danger.
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
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.
The Last Word:
Check out our playlist of videos from last April’s Professional Development Workshop. The topic of the day was “Avalanche Science, Avalanche Stories”.