Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Forecast issued on Thursday, February 7th at 7:00 a.m. Today’s forecast is sponsored by Yellowstone Arctic Yamaha in partnership with the Friends of the Avalanche Center. This forecast does not apply to operating ski areas.
Last night the Big Sky area picked up 1-2” of new snow. Skies are clearing and temperatures are -5F to -15F at ridgelines. Winds are west to north at 10 to 20 mph creating a freeze-your-face-off wind chill. Today will be sunny and temperatures will rise into the positive single digits as winds remain the same. Tonight will be partly cloudy and temps will fall to just below 0F. Scattered snowfall is expected tomorrow.
In the mountains south of Big Sky to West Yellowstone close to 2 feet of new snow fell since Saturday (1.5-2” SWE). The avalanche danger is decreasing since avalanches are getting harder to trigger, but if one breaks it could be large. There are two concerns with the snowpack, one major and one minor:
- The major concern is that sugary, weak facets at the ground are showing instability. On Tuesday, Eric and I got a loud collapse in Taylor Fork (video) and skiers nearby on Bacon Rind got one as well (details). Karl dug in Bacon Rind yesterday and found these facets 3 feet under the surface. They broke in his stability tests, but took a lot of force (snowpit profile). An unlucky person could trigger this layer with much less effort from a shallow spot.
- The minor concern is a thin layer of facets and surface hoar that was buried over the weekend. This layer is 1.5’ under the surface and is not detectable to the naked eye, nor is it on all slopes. Ian found it on Sunday in Bacon Rind (video), Eric and I saw it in Taylor Fork and others had it in Lionhead (photo). A quick compression test will inform you if it is there or not. If a slide is triggered on this layer it could step down to the ground and be deadly.
Collapsing or cracking are red flags to avoid avalanche terrain. Without these clear signs, finding slopes that are safe to ski or ride requires digging and testing (article). For today, it is still possible to trigger avalanches and the danger is rated MODERATE.
In the mountains around Bozeman, Big Sky and Cooke City, the main avalanche concern is on slopes that were wind-loaded with new snow in the last 5 days. Alex outlined these concerns in this video as the storm was beginning. A secondary issue is weak facets at the ground are still reactive in stability tests, especially in shallow areas, which Eric found in Beehive Basin (video). On Tuesday, climbers in Hyalite backed off their objective near Mt. Blackmore when these facets broke easily in their test and a skier outside Cooke City got collapses indicating lingering instability (details). For today, the avalanche danger is rated MODERATE on all slopes.
If you get out and have any avalanche or snowpack observations to share, contact us via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
Story Mill Beacon Park
Stop by the public beacon park at the Bozeman Parks North Recreation Center at Story Mill on Rouse St. It is operational from 8:30 a.m to 5:00 p.m. 7 days a week. Here’s a fun video outlining how to use the park: https://www.facebook.com/friendsgnfac/videos/279522799401278/
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
BOZEMAN
February 8 and 9, Companion Rescue Clinic, 6-8 p.m. Friday at REI, 10-4 Saturday in the field. More Info and Register.
February 22 and 23, Women’s Companion Rescue Clinic, 6-8 p.m. Friday at REI, 10-4 Saturday in the field. More Info and Register.
WEST YELLOWSTONE
February 9, 16 and 23, 1-hr Avalanche Awareness for Snowmobilers, 7-8 p.m. Holiday Inn West Yellowstone.
HELENA
February 13, 1-hr Avalanche Awareness, 6-7 p.m. at Carroll College.
COOKE CITY
Every Friday and Saturday, Rescue Training and Snowpack Update. Friday 6:30-7:30 p.m. at the Soda Butte Lodge. Saturday anytime between 10-2 @ Round Lake.
Read an article in Backcountry Magazine by Mark Staples of the Utah Avalanche Center about why it’s a good idea to dig quick pits.