Good morning. This is Doug Chabot with pre-season avalanche, weather and event information for the Gallatin National Forest Avalanche Center on Wednesday, December 8th at 7 a.m. This information is sponsored by Cooke City Motorsports and Alpine Orthopedics & Sports Medicine. We will update this bulletin on Friday.
Yesterday morning there was 7” of new snow in the Bridger Range, Big Sky area and Cooke City. Other areas got 3-4” with amounts dwindling to an inch outside West Yellowstone. Since then, west to southwest wind increased to 20-30 mph with gusts of 50 mph. Temperatures this morning are near 20F and will reach 30F, but cool into the teens tomorrow. Winds will continue to be strong today and taper off this evening. By tomorrow morning a trace to 1” of snow is expected with Cooke City getting 2”.
The snow that fell yesterday was a welcome relief; every little bit helps. Up to 7” fell (.7” of snow water equivalent), but a few places like the Lionhead area only got an inch. In all mountains the strong westerly wind is loading slopes at ridgelines and in gullies. Above 9,000 feet snow depth is about 24-30”. Below that it gets thinner. Recently, Dave has been on a low-elevation tour of thin snowpacks. On Saturday he and Alex skinned over dirt patches to get the weather station up on Flanders Mountain in Hyalite (video). On Monday, in Beehive Basin, he left his skis in the car and took a hike instead. His video shows low elevation grimness. And yesterday, he hopped on a sled at Lionhead to teach an avalanche class on 8-10” of snow.
The higher you climb the more snow there is. The difference between low and high elevations is stark, and so is the avalanche potential. On slopes that hold early season snow there is a layered snowpack. Some of these layers are getting weak as sugary, faceted snow develops. Wind-loaded slopes and gullies are cracking and avalanching. Alex and Ian are in Cooke City and rode up Fisher Creek and ski toured higher (video). They had 2-3 feet of snow, a couple weak layers in their pit and noticed wind slabs were cracking (photo) and avalanching (photo). Expect to find similar conditions across the forecast area.
On Sunday, ice climbers in Hyalite triggered a wind slab in a gully (photos and report). Since then, new snow and very strong wind has increased the chances of triggering an avalanche, especially in gullies or near ridges. Retreat as soon as you see cracks shooting out in front of you and be extra careful around smooth wind pillows. Small avalanches are indicative that more, possibly bigger ones are possible. Ice climbers are susceptible to being swept away by small avalanches. If you see a slide in a gulley you should assume there are more, untriggered drifts above you.
Ian will update this bulletin on Friday morning. If you have avalanche, snowpack or weather observations to share please submit them via our website, email (email@example.com), phone (406-587-6984), or Instagram (#gnfacobs).
Upcoming Education Opportunities:
Get your avalanche brain ready for the season at one of the many classes listed on our education calendar, and list of upcoming events below. Don’t delay preparing and inspecting your avalanche gear. Get some tips from Dave Zinn in this Pre-Season gear check video.
TONIGHT, 7-8 p.m. Online FREE 1-hr Avalanche Awareness in partnership with OnX maps. Link to Join Here.
TONIGHT, 6:30 p.m. The BROADcast, at Uphill Pursuits (women only). Avalanche conditions update by GNFAC intern Hannah Marshall folllowed by 5 women's short adventure presentations including Brett Harrington and Chantel Astorga. Beer, pizza raffle and laughs; https://bozemanicefest.com/in-town-events
Wednesday, December 15, 6-7 p.m. FREE Sidecountry Avalanche Awareness for Families (and Friends). In partnership with Bozeman Parks and Recreation at Beall Park. A 1-hr avalanche awareness talk with an emphasis on “Sidecountry Terrain and Snowpack.”
Friends of GNFAC Powder Blast Fundraiser
The Friends of the Avalanche Center are hosting the Virtual Powder Blast fundraiser. With only $3,500 left to go, help us reach the $65,000 goal. Your donations support free and low-cost avalanche education, beacon checkers at trailheads, beacon parks, weather stations, and GNFAC programs!
Bruce Jamieson of Snowline has posted avalanche science and training videos for backcountry travelers. These are worth checking out as we wait for more snow to fall.