Good morning. This is Alex Marienthal with pre-season avalanche, weather and event information for the Gallatin National Forest Avalanche Center on Wednesday, November 24th. This information is sponsored by OnX and Blitz Motorsports and Yamaha. We will update this bulletin on Friday, November 26th.
Last night the mountains received 3-6 inches of snow. Wind has been out of the northwest at 10-15 mph with gusts of 25-40 mph. This morning temperatures are mid-teens to low 20s F. Today temperatures will reach mid-20s F and wind will be west-northwest at 10-25 mph with clearing skies. The next few days will be partly cloudy to mostly sunny with temperatures reaching low 30s F during the day and teens to low 20s F at night. On Thanksgiving, strong westerly wind is expected with gusts up to 30-40 mph. There is a slight chance for maybe an inch of snow on Friday night.
Where there is enough snow to ski or ride the snowpack has layers and avalanches are possible. Last night’s snowfall of 3-6" was equal to 0.3-0.4" of snow water equivalent (SWE). Moderate northwest wind drifted the new snow into thicker layers which can break and avalanche today. Strong wind tomorrow will continue to grow these layers into thicker slabs. If these wind slabs avalanche, they could be large enough to bury a person, and certainly enough to knock someone over. Small dry loose avalanches of the new snow are also possible. Either of these avalanches are especially dangerous if they knock you over in high consequence terrain, like above cliffs, trees or the many exposed rocks right now.
On slopes that have layers of snow from October and early November avalanches might break 1-2 feet deep on old, weak snow. I saw these weak layers near Cooke City last Friday (video), and skiers near Fairy Lake reported similar layers over the weekend (photo). Until proven otherwise, I suspect there are buried weak layers on high elevation slopes throughout our advisory area.
If you go to recreate in the mountains over the next couple days plan to avoid avalanche terrain where there are fresh drifts of snow or if you suspect there are buried weak layers, especially if the terrain has high consequences of being caught in a slide. Choose objectives that give you an opportunity to safely gather data about how this season’s snowpack is looking, and provide yourself time to make clear, informed decisions.
We will issue the next update on Friday morning. We are preparing for winter, teaching avalanche classes, and setting up weather stations. If you have avalanche, snowpack or weather observations to share please submit them via our website, email (firstname.lastname@example.org), 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.
November 30, 7-8 pm, Online Free 1 hr Avalanche Awareness in partnership with The Yellowstone Club Community Foundation. Link to Join Here.
December 1, 6-8 pm, Avalanche Awareness and Beacons at Beall Park. More info on our education calendar.
Our popular Avalanche Fundamentals with Field Course is perfect as a refresher or an introduction to avalanches. We are introducing an exciting new format this year with the four lectures pre-recorded to watch at your convenience, a live question and answer session, and a choice of a snowmobile or ski/ board based field day occurring the following three weekends.
Friends of GNFAC Powder Blast Fund-raiser
The Friends of the Avalanche Center are hosting the Virtual Powder Blast fundraiser. With only $4,000 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!
Doug was interviewed by Justin Angle for Montana Public Radio about his background, avalanches, and his work in Central Asia. You can listen to the interview HERE.