Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, December 30 at 7:30 a.m. Beartooth Powder Guides and Outlaw Partners sponsor today’s advisory. This advisory does not apply to operating ski areas.
Over the past 24 hours the mountains around Cooke City have received 6-8 inches of low density snow. The rest of the advisory area has remained dry.
Currently, temperatures are in the mid-teens to low twenties F and westerly winds are blowing 10-20 mph. Today, a northwest flow aloft will continue to push weak bands of moisture over the area. No major accumulations area expected, but skies will remain mostly cloudy with a slight chance of mountain snow showers. The exception is Cooke City where 1-3 inches is possible throughout the day.
Temperatures will warm into the mid-twenties to low thirties F and winds will continue to blow predominately out of the west at 10-20 mph. A more potent storm system is forecasted to impact the area tomorrow into Wednesday.
Bridger Range Gallatin Range Madison Range
Lionhead area near West Yellowstone
During my drive through Yellowstone Park last week, I encountered numerous groups of Bison on the road. These massive beasts were not the least bit concerned as I passed by in the truck.
As long as I did not disturb them, they were not likely to disturb me. If I decided to stop, get out and approach them, I'm sure the story would end differently.
The bison remind me of our current snowpack. It can seem docile on the surface, but if harassed or poked it can become a raging beast.
Today, I recommend keeping your distance from avalanche terrain. The snowpack structure is terrible and continues to produce obvious signs of instability (video, photos). Yesterday, Doug and I skied near Hebgen Lake and found a thick slab sitting over facets (video). We didn't dare touch slopes steeper than thirty degrees and skied our skin track back to the car.
Skiers found similar conditions in the northern Gallatin Range yesterday. They triggered a few small slides and experienced widespread cracking and collapsing. This scenario can be found throughout much of our advisory area. Check out this entertaining video from the Utah avalanche center for a different look at the same problem (video).
I'll end this section with a story from the Lionhead area new West Yellowstone. A few days ago (specific date unknown) a group of snowmobilers were riding on small but steep slopes. One rider proceeded to get stuck mid slope and was approached by his partner. The slope avalanched burying multiple sleds and one guy up to his neck (photo). Nobody in this group was carrying rescue gear - not smart!
Today, the combination of slabs and weak layers makes human triggered avalanches likely and the avalanche danger is rated CONSIDERABLE.
Cooke City
Cooke City is a different beast. This area has the unique ability to pull moisture out of every passing storm. Over the past 24 hours, this area picked up 6-8 inches light-fluffy powder with more on the way. This is not a huge load, but it’s enough to keep pressure on the pack.
Today, the primary avalanche problem around Cooke City will be wind slabs. Westerly winds will easily transport the new snow onto leeward slopes. Terrain facing the east half of the compass will be the most prone to wind slab development. Avalanches breaking within the new snow won’t be huge, but they shouldn’t be scoffed at either.
It only takes a small slide to burry or injure a human, plus small sides make great triggers for larger slide. It will be possible for avalanches to break on deeper layers in the pack. Over the past few days, human triggered avalanches failing on faceted layers near the ground have been observed near Lulu Pass (video, photo).
Today, new snow and wind combined with buried weak layers will make human triggered avalanches likely on wind loaded slopes and slopes steeper than 35 degrees which have a CONSIDERABLE avalanche danger. Less steep slopes without a wind load have a MODERATE avalanche danger.
Doug will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
EVENTS/EDUCATION
January 1, BOZEMAN: Wednesday, January 1, 10 a.m., Hyalite Tour at the Hyalite Resovoir. Classic skiing, free waxing and free lunch. More info HERE.
January 4, BOZEMAN: Saturday, 10:30 a.m. at Bridger Bowl, Free Avalanche Transceiver Workshop, next to rental shop at Jim Bridger Lodge.
January 7, BILLINGS: Tuesday, 6:30-8:30 p.m. at High Mountain Recreation, 90-Minute Rescue Presentation.
January 8, BOZEMAN: Wednesday, 6:30-8 p.m. at REI, Sidecountry IS Backcountry lecture.
January 9, BOZEMAN: Thursday, 6-7 p.m. at Mystery Ranch, 1-hour Avalanche Awareness lecture.
January 9, HELENA: Thursday, 6:30-7:30 p.m. at Exploration Works, 1-hour Avalanche Awareness lecture.
January 11, COOKE CITY: Saturday, 10 a.m. to 4 p.m., Companion Rescue Clinic for Snowmobilers, Pre-Registration is required. https://www.ticketriver.com/event/9445
January 11, WEST YELLOWSTONE: Saturday, 7-8 p.m. at Holiday Inn, 1-hour Avalanche Awareness lecture.
More information our complete calendar of events can be found HERE.