GNFAC Avalanche Advisory for Tue Jan 2, 2018
Not the Current Advisory - ARCHIVED

Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on 
Tuesday, January 2nd, 2018 at 7:00 a.m. This advisory does not apply to operating ski areas.

Mountain Weather

There has been no snowfall in the last 24 hours. At 5 a.m. under clear skies, mountain 
temperatures are in the teens with near zero in the valleys. Wind is west at 10-20 mph in the 
southern ranges and 20-30 mph in the north. Today will be sunny with temperatures reaching the 
low 20s before dropping to near zero tonight and winds will ease to 10-20 mph from the west.

Snowpack and Avalanche Discussion

All Regions

The storm ended on Saturday and dropped over 4’ of snow outside Cooke City, 2-3’ in other ranges 
and a foot near West Yellowstone. Yesterday was the first day in almost a week without recent 
avalanches or signs of instability. Many natural avalanches and human triggered slides occurred 
during the storm. There were a couple of close calls when a skier was caught and injured in 
Truman Gulch on the west side of the Bridger Range on Friday and a skier was partially buried 
outside Cooke City after remotely triggering an avalanche from below on Thursday. 

Avalanches were especially numerous on slopes with a shallow snowpack, typically at lower 
elevations, since they harbor weak snow near the ground and also around an ice crust that 
formed over Thanksgiving. Some avalanches in the alpine were large and deep and broke on weak, 
faceted snow that formed at the surface mid-December.

On Sunday skiers reported collapsing and cracking near Lionhead (Hebgen Lake area) and Cooke 
City. As the days pass without new snow or significant wind-loading, the likelihood of triggering 
avalanches decreases, but my hackles are raised. Seeing avalanche crowns is exciting, but should 
serve as a reminder to be extra careful, even with stability getting better. Yesterday, folks 
in the northern Bridger Range did not ski their intended line after seeing avalanches from the 
storm and facets in the snowpack.