Good morning and happy Easter. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, March 27, at 7:00 AM. Today’s advisory is sponsored by Bridger Bowl and Gallatin County Search and Rescue. This advisory does not apply to operating ski areas.
High pressure remains over the area producing clear skies and calm conditions. This morning temperatures are in the teens to low 20s F and winds are blowing 10-20 mph out of the W-SW. Today will be one of transition as another storm system approaches from the west. Skies will start out clear this morning but become increasingly cloudy by this afternoon. Temps will warm into the upper 20s to low 30s F and winds will increase throughout the day. Snow develops over the mountains tonight with 2-4 inches possible by tomorrow morning.
Southern Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone Cooke City
The southern mountains have a snowpack structure more conducive to producing avalanches. A thin layer of facets around an ice crust buried 2-3 feet deep has produced a few natural and human triggered slides over the past week (photo, video). Slides failing on this layer are not propagating far and wide, but are big enough to carry and potentially bury a skier or rider. This facet-crust combination is not on all slopes, which means digging and testing is the only reliable method of locating it. Wind loaded slopes will also be a concern. Yesterday, a snowmobiler triggered a good sized avalanche on a wind loaded slope near Goose Creek outside of Cooke City (photo). Fortunately nobody was caught. Cornices also pose a growing threat this time of year. Yesterday, a skier outside of our forecast area near Gardiner got too close to the edge along a ridgeling and fell off a cornice which subsequently triggered a large slide on the slope below (photo). Amazingly the skier who took the ride was not buried or injured. It’s worth giving these growing monsters a wide berth along the ridgelines since they have a tendency to break farther back than you might expect.
Today, a few different problems make human triggered avalanches possible and the avalanche danger is rated MODERATE.
Bridger Range Northern Madison Range
Northern Gallatin Range
The northern mountains have received up to 2 feet of snow over five days. The new snow has had time to settle and is well bonded to the firm old snow surface (video). Yesterday, my partners and I skied north of Bridger Bowl and fond the new snow reluctant to move, even on steep slopes. We did observe a few small point releases near south facing rock bands, but the wet snow danger was minimal. Skiers near Hyalite and Big Sky found similar conditions. Today, there will be a thin sun crust on all but north facing slopes. This will decrease the skiing and ridging quality. If you are on the hunt for powder, watch for small wind slabs near the ridgelines. These should be fairly glued on, but could produce small avalanches with human triggers. Outside of this isolated instability there will be minimal avalanche hazard.
Today, generally safe avalanche conditions exist and the avalanche danger is rated LOW.
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.
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