Good morning. This is Ian Hoyer with the Gallatin National Forest Avalanche Forecast on Friday, January 7th at 7:00 a.m. This information is sponsored by Blitz Motorsports and Yamaha and onX. This forecast does not apply to operating ski areas.
In the past 24 hours, 4-6” of snow fell near Big Sky and West Yellowstone, 6-8” near Bozeman, and 15” around Cooke City. Strong west and southwest winds have been blowing 20-35 mph with gusts of 45-70 mph and will continue today. Temperatures are in the 20s F this morning and will rise into the high 20s and low 30s F. A trace of snow will fall around Bozeman today, 1-3” near Big Sky and West Yellowstone, and 3-4” in Cooke City.
Heavy snow and strong winds are creating very dangerous avalanche conditions. 15” of snow has fallen since yesterday moring (1.5” of snow water equivalent) and it is still snowing. Strong winds have created fresh drifts 2-4 ft deep. Expect steep wind-loaded slopes to avalanche naturally today. If you get onto any steep slope, even one that isn’t wind-loaded, expect to trigger a slide beneath the new snow. With so much new snow these storm snow avalanches will easily be large enough to bury you. If you need added incentive to stay out of avalanche terrain, remember that there are weak layers lower in the snowpack that could break even deeper (Mt. Abundance photo).
Snow tapered off early yesterday afternoon, leaving 5-6” of new snow (0.5-0.6” SWE). Since the end of snowfall, slopes sheltered from the wind have gotten a bit of a break with warm temperatures helping the new snow to bond. Strong gusty winds are still actively drifting snow and stressing the snowpack on wind-loaded slopes. With unusually strong winds, expect drifts in unusual places at lower elevations and in spots that may typically be sheltered from the wind. Wind slab avalanches will be easily triggered on wind-loaded slopes today. Avalanches were already breaking on wind-loaded slopes before this latest round of snow, potentially on a freshly buried weak layer (Lionhead avalanche photo). Skiers near Hebgen lake yesterday got quite unstable snowpack test results on the weak snow at the ground. Those weak layers need more time to adjust to this load before we will trust them. The avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on all others.
Skiers in the Bridger Range yesterday reported small natural and skier triggered slides (photo, photo, photo). While these slides were not large, they demonstrate unstable conditions and the potential for larger slides breaking on more heavily wind-loaded slopes. Warm temperatures have helped the storm snow bond and it will be less reactive today. Keep an eye out for cracks shooting out in front of you as a sign you’ve found a place where the new snow hasn’t yet bonded. If you’re going to get onto steep slopes, dig a snowpit and check for unstable weak layers lower in the snowpack (Mt. Ellis video). Human triggered avalanches are possible and the avalanche danger is MODERATE today.
Upcoming Education Opportunities
See our education calendar for an up-to-date list of all local classes. Here are a few select upcoming events and opportunities to check out:
January 20 + Field day. Our popular Avalanche Fundamentals with Field Course 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 a choice of a snowmobile or ski/ board based field day occurring the following two weekends.
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 West Yellowstone Beacon Park is up and running! Stop by to check it out and practice with your rescue gear.