Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Forecast issued on Friday, February 8th at 7:15 a.m. Today’s forecast is sponsored by Yellowstone Club Community Foundation and Montana State Parks. This forecast does not apply to operating ski areas.
This morning an inch of snow fell in Hyalite and a trace in the Bridger Range. Under mostly cloudy skies, temperatures are near 0F and winds are west to southwest averaging 10-20 mph with gusts of 30 mph. Today will warm to the teens with scattered snowfall and winds of 20 mph from the west to southwest. By morning most locations will have 1-2” of new snow with more falling on Saturday.
As we drove down the highway toward West Yellowstone yesterday, Alex and I spotted four impressive avalanches on Lionhead ridge (video, 5 photos). The largest was 4+ feet deep, a few hundred feet wide and triggered by a sledder on Wednesday. It was big enough to kill. This avalanche, as did two others, broke on the 1-2 foot thick layer of sugary facets that underlay our season’s snowpack. The fourth slide involved new snow. These avalanches ripped out older snowmobile tracks shattering the myth that tracks mean a slope is safe.
Two feet of snow fell over the weekend and prompted an avalanche warning on Monday. Since then, triggering avalanches are more difficult, which is good news. However, evaluating which slopes are dangerous and which are safe is challenging. Alex and I were careful as we rode under bigger slopes, only going one at a time. The snowpack structure is worrisome in the mountains south of Big Sky to West Yellowstone (video, snowpit). A skier or rider could trigger a large slide by either breaking off a cornice or hitting the weakest part of a slope, typically the shallowest.
The avalanche danger is rated MODERATE today, but it’s a serious Moderate.
In the mountains around Bozeman, Big Sky and Cooke City there has been no avalanche activity in over a week and only isolated signs of instability. Yesterday in Beehive Basin a skier got cracking on wind slabs (photo) and another party stuck to low angled trees when their tests broke on sugary facets on the bottom 2 feet of the snowpack, similar to Eric’s finding on Monday (video). A couple days ago skiers outside of Cooke City felt a large collapse while they dug a pit, fracturing a faceted layer in the middle of a 190 cm deep snowpack (details). And last Friday, Alex got a rumbling collapse to the north of Cooke City on a shallow, weak slope (video). These disparate signs of instability are not unusual and luckily we have protocol for these types of situations: we dig and assess the snow under our feet, and we retreat to low angled terrain when we get collapses or cracks. Winds yesterday and last night likely created wind drifts at the ridgelines and in gullies that will crack and potentially avalanche. For today, avalanches on wind drifts and deeper in the snowpack are possible and the danger is rated MODERATE.
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 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.