Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, January 18th at 6:45 a.m. Today’s advisory is sponsored by Montana Ale Works and Gallatin County Search and Rescue. This advisory does not apply to operating ski areas.
At 5 a.m. an inversion shows below freezing temperatures in the valleys and 34-37F in the mountains around Bozeman and Big Sky. In the southern ranges temperatures are 10-20F this morning and will reach the mid-30s this afternoon. Winds are W-SW at 20-30 mph with gusts near 40 and Lulu Pass outside Cooke City is recording north winds at 10-20 mph. Today, winds will remain the same, skies will be partly cloudy and mountain temperatures will drop to below freezing tonight.
Madison Range Gallatin Range Lionhead area near West Yellowstone Cooke City
South of Bozeman to Big Sky, West Yellowstone and Cooke City, the snowpack has 2 weak layers responsible for avalanches, collapsing and poor stability test scores (snowpits). One layer is on the ground and the other formed at the surface before the last snowstorm ended 6 days ago. Since then, the likelihood of triggering avalanches has decreased, but remains possible. A natural avalanche in Beehive Basin on Sunday failed on weak, sugary snow at the ground (depth hoar) when a small, wet loose avalanche hit a thin part of the slope (photo). Alex and I investigated the slide and made a video. Skiers in the northern Gallatin Range on Monday saw recent avalanches (photo1, photo2) and had collapsing and cracking on wind-loaded slopes. Separately, Alex and Eric found improving stability on the depth hoar facets at the ground in Bacon Rind and Taylor Fork late last week. Around Cooke City the snowpack is 5-7 feet deep and is holding together after last week’s large snowstorm. Recent avalanches have been small (photo) and the ability to trigger slides is decreasing, but on the edges of slopes where the snowpack is thin the weight of a skier or snowmobiler could trigger a deep avalanche.
Eric outlines our snowpack concerns succinctly in this video he made up Buck Ridge on Saturday. The snowpack structures has not changed since then, just the chances of triggering avalanches. For today, the avalanche danger is rated MODERATE. Additionally, if temperatures are above-freezing and skies remain clear, sun exposed slopes will have wet loose avalanches.
Bridger Range
The Bridger Range has been windy this week, but without new snow to blow around and above freezing temperatures gluing wind slabs in place, triggering avalanches is unlikely. The snowpack is weak and consists of thick layers of facets, but without a snow load is generally stable. Above freezing temperatures this morning means wet loose avalanches may occur with the morning’s sun. For today the dry snow avalanche danger is rated LOW and the wet snow avalanche danger could rise to MODERATE on sunny slopes.
Check out our photos, field day videos and snowpits to get a thorough understanding of the snowpack.
Eric will issue the next advisory tomorrow morning by 7:30 a.m.
We rely on your field observations. Send us an email with simple weather and snowpack information along the lines of what you might share with your friends: How much new snow? Was the skiing/riding any good? Did you see any avalanches or signs of instability? Was snow blowing at the ridgelines? If you have snowpit or test data we'll take that too, but this core info is super helpful! Email us at mtavalanche@gmail.com or leave a message at 406-587-6984.
Month of January: Montana Ale Works has chosen the Friends of the Avalanche Center as January's "Round It Up America" recipient. Every time you round-up your bill the change gets donated to the Friends. Pennies equal dollars!
King and Queen of the Ridge, Saturday, February 4th. A Hike and Ski/Ride-a-Thon fundraising event to support the Friends of the Gallatin National Forest Avalanche Center. Register with Bridger Bowl HERE, make pledges HERE.
BOZEMAN
TONIGHT! Evenings 18-19 January, field 21 or 22 January. Introduction to Avalanches with Field Course, 7-9:30 p.m. at MSU Sub Ballroom B. Sign up HERE.
COOKE CITY
Weekly rescue training and snowpack update, 6-7:30 p.m., The Antlers Lodge on Friday, field location Saturday TBA.
WEST YELLOWSTONE
January 21, Avalanche Awareness, 6-7:30 p.m., West Yellowstone Holiday Inn.
DILLON
February 4 and 5, Intro to Avalanches with Field Day, More info and sign up HERE.