GNFAC Avalanche Forecast for Thu Feb 10, 2022

Not the Current Forecast

Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Forecast on Thursday, February 10th, at 6:45 a.m. This information is sponsored by Gallatin County Sheriff Search and Rescue and Grizzly Outfitters. This forecast does not apply to operating ski areas.

AVALANCHE FATALITY REPORT AND VIDEO

We completed our investigation of the avalanche fatality at Ski Hill in Lionhead. A detailed report is HERE, the field video is on our YouTube channel and the incident is recorded on our Accident Reports page.

Mountain Weather

Big Sky is reporting 1-2” of new snow along with an inch in Hyalite and Cooke City. Everywhere else either got missed or received a dusting. Wind remains steady from the W-N averaging 10-20 mph with gusts of 35 mph and 53 mph on the Bridger ridge. Under partly cloudy skies, mountain temperatures are in the mid 20s and will reach above freezing today. Clouds will stream in later today but snowfall will only be a trace to 1” overnight. :(

Snowpack and Avalanche Discussion

It remains possible to trigger avalanches in the mountains around Cooke City. The reason is two-fold. First, there is a buried weak layer of sugary, faceted snow (and surface hoar) a foot and a half under the surface. This layer is responsible for many days of collapses, cracks, avalanches and poor test scores in snowpits (details). Yesterday a skier felt large collapses south of town in Wyoming Creek (details). This matches the concerns Alex had during his visit this week (video). Second, it has been windy enough to move snow around which loads slopes even when it is not snowing. 

Collapses (whumpfs), shooting cracks, and the mother of bulls-eye information, avalanches, are blinking signs to avoid avalanche terrain. Even without those signs, remember to only expose 1 person at a time to avalanche terrain. For today the avalanche danger is rated MODERATE on all slopes.

 

Last night’s minor snowfall around Big Sky and Hyalite will not affect the general stable conditions we are finding in the mountains from Bozeman to West Yellowstone. Weak layers of small, sugary facets and two stripes of feathery surface hoar crystals can be found 12-18” under the surface (photo, snowpit profile). This layer is widespread yet only unstable in small, isolated areas where wind drifting has capped it with a dense slab of snow. This recipe is what allowed a snowmobiler to trigger a small but deadly slide on Sunday in Lionhead (details). Once snowfall resumes, this weak layer will become unstable over wide swaths of our forecast area, but until then, avalanches are unlikely. Even with a stable snowpack we have to keep up our safety rituals. Just like buckling a seat-belt for a short drive, we need to always carry our rescue gear (beacon, shovel and probe) and literally only expose one person at a time in avalanche terrain. For today the avalanche danger is rated LOW on all slopes. 

If you get out, please send us your observations no matter how brief. You can submit them via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).

 

Upcoming Education Opportunities

See our education calendar for an up-to-date list of all local classes. Here are a few select upcoming 

TONIGHT! Forecaster Chat at Uphill Pursuits, “Beyond the Beacon”, 6:30 p.m., with GNFAC forecaster Dave Zinn. 

February 11-12, Avalanche Fundamentals + Field Day in ENNIS is perfect as a refresher or an introduction to avalanches. We are introducing a new format with four pre-recorded lectures to watch at your convenience, a live question and answer session, and an in-person field day. Pre-register HERE.

February 19, Women's only Companion Rescue Clinic sponsored in partnership with SheJumps! Register Here.

Every Saturday near Cooke City, 10 a.m.-3 p.m. FREE snowpack update and transceiver/rescue training. Stop by for 20 minutes or more at the Round Lake Warming Hut.

The Last Word

On Sunday, one snowmobiler in a group of four was caught and killed in a small avalanche on Ski Hill at the south end of Lionhead Ridge. We made a video explaining the event and will post a detailed report very soon. We also uploaded more pictures from our investigation to the Avalanche Incidents page.


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