Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Advisory issued on Saturday, January 2, at 7:30 a.m. Today’s advisory is sponsored by Mystery Ranch and Cooke City Motorsports. This advisory does not apply to operating ski areas.
At 4 a.m. the bank’s thermometer across the street is showing 4 degrees F and temperatures in the mountains are in the 20s F. Wind is blowing 5-15 mph out of the E-SE. Today will be sunny and the inversion will continue with mountain temperatures in the 20s to low 30s F. Wind will be 10-15 mph out of the southeast and shift to the south throughout the day. Clear skies and dry conditions will continue through the first half of the week.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
The mountains throughout our advisory area contain an unstable snowpack structure. A layer of sugary, weak depth hoar that formed on the ground in November is capped by a slab of snow that is at least 2-4 feet thick. Visit our video page for explanations of this poor structure in the areas we have visited. Avalanches were observed or triggered every day between December 14 and the new year (what’s been happening, photo page), and there was a fatality in Cooke City exactly two weeks ago on December 19 (video). Snowfall and wind were minimal this past week and avalanche activity has subsided, but avalanches were triggered by snowmobilers in Cooke City (video, photo, photo, photo, photo) and a skier in the Northern Gallatin range (photo).
Obvious signs of instability are scarce, partly because people are being conservative and avoiding steep terrain. When we don’t see avalanches or get collapsing and cracking of the snowpack we feel more comfortable with the stability. Without obvious signs of instability you have to dig a snowpit to look for the depth hoar at the ground, or assume that it is there. Avalanches are becoming less likely and more difficult to trigger, but human triggered avalanches are still possible.
If you trigger an avalanche it could be deep and large, so for today the avalanche danger is rated CONSIDERABLE on all slopes steeper than 35 degrees and MODERATE on less steep slopes.
Eric will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations to share, drop us a line at mtavalanche@gmail.com or leave a message at 587-6984.
EVENTS and AVALANCHE EDUCATION
A complete calendar of classes can be found HERE.
TONIGHT!! West Yellowstone: 1hr Avalanche Awareness, West Yellowstone Holliday Inn, 7-8:30 p.m.
Bozeman: January 6, Women’s Avalanche Awareness and Beacon 101, Beall Park, 6-8 p.m.
January 9 and 10, Companion Rescue Clinic, REI, Fri 6-8p.m., Sat 10a.m.-2p.m.
January 13, 1hr Avalanche Awareness, REI, 6-7:30 p.m.
Livingston: January 14, 1hr Avalanche Awareness, Neptune’s Brewery, 6-7:30 p.m.
Dillon: January 19, 1hr Avalanche Awareness, UM Western Library, 6:30-8 p.m.
ASMSU Intro to Avalanches w/ Field Course
January 20, 21 and 23 or 24: https://www.ticketriver.com/event/16861
The workshops will be held on Wednesday and Thursday evenings, with a field course on either Saturday or Sunday. Different topics will be presented each evening. Topics include: avalanche terrain recognition, the effect weather has on avalanche hazard, the development of the mountain snowpack, decision making skills, and basic search and rescue procedures.