Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Forecast on Thursday, December 5th at 7:00 am. This information is sponsored by the Bozeman Ice Festival, Bridger Bowl, and Yellowstone Ski Tours. This forecast does not apply to operating ski areas.
This morning under clear skies, temps are mostly in the upper 20s F, and winds from the W & NW are averaging 5-10 mph with gusts up to 20 mph.
Today will have more warm beautiful weather with mild temps rising into the low to mid 30s F at upper elevations. Winds will be decreasing and barely blowing by afternoon.
This weekend a trough of low pressure will descend over Montana bringing cold air and snowfall on Sunday. At the moment, forecast models are only showing brief ridging (aka warm & dry weather) in the middle of next week followed by a series of troughs (aka storms) rolling across the western U.S. The main point is that there are no large ridges of high pressure in the long term forecast which is promising.
Two things are happening in the snowpack:
(1) Stability is steadily increasing the longer the snow sits without loading from snowfall or wind. A good example is at Big Sky where the ski patrol triggered decent avalanches a week ago, but now is not triggering much as they work around Lone Mountain on a snowpack that resembles the backcountry.
(2) The snow surface continues to weaken and facet under crystal clear, night skies. A good crop of surface hoar has been growing as well. We’ve certainly seen worse, but the current snow surface could easily become the weak layer for future avalanches. For now, it makes for nice skiing and riding.
With clear skies and more sunshine today, wet loose avalanches are a remote possibility but unlikely because the snow on sunny slopes has been through several melt-freeze cycles.
On average the snowpack is only about two feet deep and you can find weak layers in the bottom foot of snow as Ian and Dave found in the Taylor Fork on Tuesday, and Ian and his partner found yesterday along Buck Ridge near Big Sky.
With no notable recent avalanche activity, no recent loading from snowfall or wind, and no other obvious signs of instability, all indications are that human triggered avalanches are unlikely and the avalanche danger is LOW. The greatest danger is hitting rock and stumps.
Conditions near Cooke City are very similar to the rest of the forecast area. The one main difference is that the snowpack produced audible collapses for an experienced skier on Monday in the valley bottom and near ridgetops on east and west aspects south of town. These obvious signs of instability can’t be ignored and mean that persistent slab avalanches about a foot deep are possible. Wet loose avalanches are unlikely but watch for signs that the snowpack is getting wet under today’s sunshine. Today the avalanche danger is MODERATE.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
Tuesday, December 10, 9 a.m.-3 p.m., West Yellowstone Avalanche Fundamentals: Motorized Guide Cert Course, Pre-registration required.
For an intro class with a field day, Register for our Avalanche Fundamentals course.
Friends of the Avalanche Center: Fall Fundraiser!
We’re still counting on your support and the online Fall Powder Blast fundraiser is 79% of the way to our goal. Please consider making even a small donation HERE or via Venmo