Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Center’s early season avalanche information issued on Thursday, December 1st at 7:30 a.m. Today’s bulletin is sponsored by World Boards and Katabatic Brewing Co.
Over the past 24 hours 3-5 inches of snow fell in the mountains around Bozeman and Big Sky. The mountains around West Yellowstone and Cooke City picked up 1-2 inches. At 5 a.m. temperatures are in the teens F and winds are blowing 10-15 mph out of the W-NW. Today, highs will warming into the 20s under mostly cloudy skies and winds will remain light to moderate out of the W-NW. Light snow showers are expected throughout the day and the mountains should pick up an additional 1-3 inches by tomorrow morning. A weak ridge of high pressure builds over the area tomorrow, but another storm is expect to impact the area Sunday and Monday.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
It’s starting to look and feel like winter in the mountains. Small but frequent storms are starting to add up. In the mountains around Bozeman, Big Sky and Cooke City, snow depths ranging from 18” to 24” can be found in terrain above 8,000 ft. The mountains around West Yellowstone have about a foot of snow on the ground (video, photo).
Deeper snow exists on wind loaded slopes, which also hold the highest avalanche danger video. Unfortunately, wind loaded slopes hold the deepest and most consistent skiing conditions. If you’re out looking for turns, pay close attention to obvious signs of instability such as cracking and collapsing. These are Mother Nature’s clues the snowpack is unstable. Yesterday, both the Bridger Bowl and Big Sky Ski Patrols reported cracking and collapsing in wind loaded terrain. The Big Sky Ski Patrol also triggered a sizable avalanche on a north facing slope during control work. This slide failed on weak, faceted snow near the ground.
Although wind loaded slopes are the most prone to producing avalanches, steeper, non-wind loaded slopes also need to be approached with caution. I would be especially careful on north facing slopes, which may have more of a cohesive slab sitting over weaker snow near the ground. With more snow and wind on the way, I expect the avalanche danger to remain elevated. Pay close attention to changing conditions and always be thinking about the consequences of a slide.
I will update this bulletin tomorrow morning. We will begin issuing daily advisories and danger ratings when we get more snow.
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
6 December, Avalanche Awareness, 6-7:30 p.m. at MSU with Backcountry Squatters Ski Club, SUB Procrastinator Theater.
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.
BUTTE
TOMORROW! 1 December, Snowmobiling In and Identifying Avalanche Terrain, 6-7 p.m. at Redline Sports
HELENA
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, Cooke City Chamber of Commerce 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., location TBA