This is Mark Staples with pre-season information from the Gallatin National Forest Avalanche Center on Monday, November 25th at 7:00 am. This information is sponsored by Spark R&D and Montana State Parks. You can donate to the Friends of the GNFAC’s Fall Fundraiser HERE.
We’re gearing up to start daily forecasts and danger ratings very soon. Alex will issue the next update on Wednesday morning.
Winter is here in full force. This weekend started warm and windy on Saturday when temperatures dropped and snow fell Saturday through Sunday morning.
Snowfall: 6-10 inches of snow fell throughout the forecast area (0.3-0.9” SWE)
Winds: Strong winds from the SW gusting to 50 mph blew Saturday ahead of snowfall. They were much lighter Sunday, and increased some Monday morning blowing 10-20 gusting to 30 mph from the W.
Temperatures: They started quite warm Saturday morning, cooled quickly by Sunday, and are hovering in the teens F Monday morning.
This week: Winds from the SW will bring 2-3 inches of snow on Tuesday. By Tuesday evening, winds switch and will come from the NW keeping temperatures on the cold side this week with overnight lows in the single digits and teens F. There’s at least a chance of snow later this week but no major storms. No major winds are expected except to the north which could impact the Bridger Range the most
All Regions
Snow depths are highly variable but are about 2 feet at most SNOTEL sites while higher locations above 9000 ft have nearly 3 feet of snow in some areas.
Wind slab avalanches remain the primary concern. Saturday’s very strong winds from the W and SW moved some snow and created slabs 3-6 inches deep as one group found on the Bridger Ridge. With fresh snow from Sunday, Monday’s increased winds from the W have snow to transport and form deeper slabs.
HEADS UP for other problems - Overall the snowpack is off to a good start with no widespread faceted layers at the moment. In places like the Bridger Range, the snowpack was dense and even a touch wet on Friday which is good. HOWEVER, I have two concerns:
- Areas with shallower snow like I found on Lionhead on Saturday (video), OR upper elevation slopes above 9000’. North facing slopes that harbor old October snow that faceted caused several slides up to 2 feet triggered by the Big Sky Ski Patrol. Other slopes may have some facets near a crust as one experienced guide found last week near Cooke City on a SW facing slope at 9700’ and another guide found on a similar slope this weekend.
- Cold weather this week could start to weaken our fledgling snowpack if we don’t get more snow. Fingers crossed for more snow. Time will tell and we’ll be watching it.
What to do? The main strategy is to avoid recently wind loaded slopes where triggering a wind slab avalanche is possible (video of a good example from Northern Bridgers). Also, be suspicious of the snowpack and possible faceted layers that could lead to a larger avalanche if you travel above 9000’.
Your observations are incredibly valuable. Contribute to our community’s knowledge by submitting your observations, and look through our observation page for additional information before your next backcountry adventure.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
Tuesday, November 26, 6-7 p.m. Free Avalanche Awareness at REI Bozeman.
Monday, December 2, 6:30 p.m. MAP community partnership night and 1-hr Avalanche Awareness, at MAP Brewing
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 77% of the way to our goal. Please consider making even a small donation HERE or via Venmo