Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, April 3, at 7:00 AM. Today’s advisory is sponsored by Gallatin County Search and Rescue and Montana Ale Works. This advisory does not apply to operating ski areas.
At 5 a.m. temperatures are hovering right around freezing with the highest elevations dropping slightly below freezing. Skies are partly cloudy and winds are blowing 10-25 mph out of the west. Today, highs will warm into the mid to upper 40s F under partly cloudy skies. Winds will continue to blow 15-25 mph out of the west with a few ridgetop gusts exceeding 30 mph. There is a slight chance of mountain snow showers this evening with a better chance of precipitation tomorrow into Tuesday.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
In many locations temperatures failed to drop below freezing overnight. In the highest elevations temps did drop below freezing but only by a few degrees. Clear skies this morning will allow for some radiational cooling, which will help to lock up the snow surface. However, as temps quickly warm and the sun comes out, it won’t take long for the snow surface to soften and destabilize.
Signs of instability such as pin wheels and point releases are clear indicators that surface layers are becoming unstable. Yesterday, the Bridger Bowl Ski Patrol reported a pin wheel that grew upwards of six feet tall as it rolled downhill. They ended up closing much of their steep terrain by 1 p.m. and today I expect earlier closures.
Today, loose wet avalanches will have the ability to entrain large volumes of snow, which could carry or potentially bury a skier or rider (video). Loose snow avalanches also make good triggers for larger slab avalanches. Yesterday, a snowmobiler near Daisy Pass outside of Cook City triggered a wind loaded slope that broke 2-4 feet deep (photo). This slide failed a deeply buried weak layer, which is a good reminder these deeper instabilities still exist. These layers can’t be found on every slope (video), but given the recent avalanche activity over the past week (photos), I would assume these deeper instabilities exist until proven otherwise.
An additional problem will be cornices. As these monstrous pieces of snow lose strength due to above freezing temps, they will be easier to trigger and may even fail naturally. It’s a good idea to give cornices a wide berth along the ridgelines and avoid traveling on or underneath slopes where large cornices are present.
Today, the wet snow avalanche danger will start out LOW but quickly rise to CONSIDERABLE as temps warm and the sun comes out. The dry snow avalanche danger is MODERATE on upper elevation, north facing slopes – primarily in areas that have been wind loaded.
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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