Our website is having issues. The danger map and some weather station links are not working and we are looking into it. I’m blaming it on the cold temperatures.
Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, December 7th at 6:45 a.m. Today’s advisory is sponsored by Yellowstone Club Community Foundation and Montana State Parks. This advisory does not apply to operating ski areas.
Last night a trace of snow fell with light winds out of the southwest to west. Mountain temperatures rose to the single digits yesterday before dropping to -10F this morning. Under mostly sunny skies temperatures will warm to a few degrees above zero and fall to -15F early tomorrow morning. Winds will remain light and no new snow is expected in the next 24 hours, but Thursday night into Friday looks promising for snowfall and warmer temperatures.
Southern Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone
The southern mountains from West Yellowstone to Big Sky have less than 3 feet of snow with the bottom layer consisting of weak, faceted crystals (video, photo). This week’s frigid temperatures will help these facets grow bigger and weaker. A sledder near West Yellowstone reported sinking to the dirt with his sled, a sure sign of unsupportable, weak snow. Strong winds Sunday and Monday loaded slopes with additional weight creating a CONSIDERABLE avalanche danger. Slopes without a wind-load have a MODERATE danger.
Cooke City
The mountains around Cooke City have lots of snow with 2+ feet falling over the weekend. On the heels of the storm a skier triggered an avalanche in this new snow (photo). A couple days without wind and snowfall means slopes won’t be as hair-trigger to avalanching. There is close to 5 feet of snow in the higher elevations and snowpits have revealed a couple weak layers of sugary-grained facets near the ground. Time will tell if this structure gets stronger before the next wallop of snow. Triggering avalanches is still possible today and the danger is rated MODERATE.
Northern Gallatin Range Northern Madison Range Bridger Range
The mountains around Big Sky and Bozeman have close to 3 feet of snow. These mountains also have a weak layer of facets near the ground that will become weaker with the sub-zero temperatures. This layer is prominent above treeline and also north aspects (video). Alex and I were able to feel for it with our ski poles in the Bridger Range on Sunday and our snowpit revealed it to be unstable (video). Yesterday, the Big Sky Ski Patrol was able to trigger a couple avalanches on this layer with explosives, a sign of its inherent instability. For today, triggering avalanches is still possible and the danger is rated MODERATE.
I will issue the next advisory tomorrow morning at 7:30 a.m.
We rely on your field observations. Send us an email with simple weather and snowpack information along the lines of what you might share with your friends: How much new snow? Was the skiing/riding any good? Did you see any avalanches or signs of instability? Was snow blowing at the ridgelines? If you have snowpit or test data we'll take that too, but this core info is super helpful! Email us at mtavalanche@gmail.com or leave a message at 406-587-6984.
BOZEMAN
TONIGHT! 7 December, Avalanche Awareness, 6-7:30 p.m. at REI.
15 December, Avalanche Awareness and Beacon Practice, 6-8 p.m. at Beall Park.
BIG TIMBER
TONIGHT! 7 December, Snowmobiling In and Identifying Avalanche Terrain, 6-8 p.m., American Legion.
HELENA
TOMORROW! 8 December, Avalanche Awareness, 6-7:30 p.m. at The Basecamp.
WEST YELLOWSTONE
15 and 16 December, Snowmobile Introduction to Avalanches w/ Field Day, West Yellowstone Holiday Inn Conference Hotel. More info and sign up HERE.
COOKE CITY
Every Friday and Saturday, Weekly rescue training and snowpack update, Super 8 on Friday 6-7:30 p.m. and field location TBA for Saturday.
BILLINGS
15 December, Snowmobiling In and Identifying Avalanche Terrain, 6-8 p.m., Big Horn Resort.