Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, January 18 at 7:30 a.m. Today’s advisory is sponsored by Montana Import Group in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
A ridge of high pressure over the Pacific Northwest is responsible for warm, sunny and windy conditions over SW Montana. This morning mountain temperatures were in the mid 20s F with valley temperatures in the mid teens F. Westerly winds were averaging 15-30 mph with gusts reaching 40-50 mph. Winds will remain strong today and temperatures should approach 32 degrees F, but some places like the Bridger Range could see temperatures in the 40s F.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
In many places there is little snow left for winds to transport (photo). Today’s strong winds will find the last remaining snow crystals and move them to the lee sides of ridges and gullies. Most wind slabs are at least 24-48 hours old. These wind slabs will be more difficult to trigger as more time passes but they remain the primary avalanche problem today.
Another problem is a layer of weak, faceted snow crystals buried 6-16 inches deep (snowpit). Because this layer is not buried deeply but could produce an avalanche, dig multiple snowpits about two feet deep taking less than a minute for each. This layer seems to be weakest in areas with a snowpack 3 feet deep or less. Also, it mostly exists in areas below treeline that don’t usually see much wind. Slopes with soft powder are prime locations to find this layer. It is worth noting that two days ago this layer produced collapsing and cracking for me just north of Big Sky on a southerly aspect, a clear sign of instability, and Eric and Karl found this layer capable of producing long crack propagations where it was capped by a hard wind slab (video), another sign of instability.
With this weak layer lurking on some slopes and hard wind slabs on others, triggering an avalanche today is possible, and the avalanche danger is rated MODERATE.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
Practice using your beacon – The Friends of the Avalanche Center in partnership with the City of Bozeman Recreation Department recently installed a beacon training site at Beall Park. It’s free and easy to use.
TOMORROW, January 19, Companion Rescue Clinic for Snowmobilers in Cooke City starting at Cooke City Motorsports at 9:30 a.m. This 6-hour clinic teaches how to use avalanche rescue gear and perform an avalanche rescue. Registration is required. For more info and to sign up, visit: https://www.ticketriver.com/event/4980-companion-rescue-clinic-for-snowmobilers
Saturday, January 19, 6 -7 p.m., 1-hour Avalanche Awareness at the Cooke City Community Center.
Wednesday, Thursday, and Saturday, January 23, 24, and 26. MSU Introduction to Avalanches with Field Course. Wed and Thurs evenings and all day Saturday. For more information and to register, visit: https://www.ticketriver.com/event/4970-introduction-to-avalanches-w--field-course