Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, March 6, at 7:00 AM. Today’s advisory is sponsored by Yellowstone Club Community Foundation and Spark R & D. This advisory does not apply to operating ski areas.
At 5 a.m. there is no new snow to report and mountain temps range from the 20s to 30s F. Winds are blowing 15-30 mph out of S-SW. Today, a storm will move into the area producing widespread valley rain and mountain snow. Precipitation will begin by late morning-early afternoon and will continue through the day. Expect strong winds and rapidly dropping temperatures as the storm moves into the area. By tomorrow morning the mountains south of Bozeman will likely see 3-6 inches of new snow while the Bridger Range will see 2-4 inches.
Southern Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone Cooke City
Two natural slab avalanches were observed in mountains outside of Cooke City yesterday. One occurred on the Fin south of town (photo), while the other took place on Scotch Bonnet near Lulu Pass. Both slides boke 1-1.5 feet deep and appeared to be the result of wind loading. It’s unknown what layer these slides failed on, but it could be a thin layer of facets sitting over an ice crust.
My partner and I found a similar set up on a SW facing slope in Cabin Creek on Friday. We got mixed results in stability tests, but agreed it was a set up that could produce avalanches. We also found a layer of buried surface hoar 18” below the surface (video). This layer has been the culprit for most avalanche activity over the past few weeks (photo). These layers do not exist on every slope, so it’s worth digging and doing a quick stability test before jumping into steeper terrain.
Today, new and windblown snow will be adding stress to buried weak layers along with creating new snow instabilities. Pay close attention to changing conditions and avoid steeper terrain if new snow and wind increase the avalanche hazard.
Today, human triggered avalanches are possible and the avalanche danger is rated MODERATE. The avalanche danger could rise to CONSIDERABLE on wind loaded slopes with the arrival of today’s storm.
Bridger Range Northern Madison Range
Northern Gallatin Range
Two words summed up yesterday’s weather – warm and windy. These conditions softened the snow surface on all aspects, but strong winds and intermittent cloud cover prevented widespread wet snow activity. A wet snow avalanche was reported outside of your forecast area in Blue Gully drainage up Pine Creek in the Absaroka Range. This slide was reported by ice climbers who fortunately were done with their climb when the slide came down.
This morning cooler temps will keep the snowpack locked up, which will produce mostly stable conditions. The main avalanche hazard will be new and windblown snow. This won’t be a problem until the storm arrives later today. Pay attention to changing conditions and avoid steep terrain if instability is on the rise.
Today, the avalanche danger will start out LOW, but could rise to MODERATE on wind loaded slopes as the day progresses.
I will issue the next advisory tomorrow morning by 7:30 a.m. If you have any snowpack or avalanche observations to share, drop us a line at mtavalanche@gmail.com or leave a message at 587-6984.
EVENTS and AVALANCHE EDUCATION
A complete calendar of classes can be found HERE.
Bozeman: Wednesday, March 9, 6-7 p.m. 1-hr Avalanche Awareness, REI.