Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Saturday, March 22 at 7:30 a.m. Gallatin River Lodge and Beartooth Powder Guides sponsor today’s advisory. This advisory does not apply to operating ski areas.
Overnight the Bridger Range picked up two inches of pixie dust (low density snow) while the rest of the advisory area remained dry. This morning, temperatures are in the single digits and winds are light out of the WNW. Today, a weak northwest flow will make light snow showers possible in the mountains around Bozeman and Big Sky although no real accumulations are expected. Temperatures will warm into the upper teens to low twenties F and winds will remain light out of the WNW. Skies will become partly cloudy by late morning and there’s a good chance from some sunshine this afternoon.
Bridger Range Gallatin Range Madison Range
Lionhead area near West Yellowstone Cooke City
Snow holds a lot of secrets. Sometimes these secrets are revealed easily and without much provocation. Other times, snow requires mindful and diligent practices in order to acquire helpful information. Without much new snow and wind, the snowpack is becoming tight lipped.
Wind slabs near the ridgetops will be the easiest avalanche problem to figure ou today. These slabs are not overly sensitive, but if triggered could break deeper than one might expect. Avoid wind loaded areas, especially in steep-high consequence terrain.
A trickier and more dangerous problem will be avalanches failing on deeper layers in the snowpack. On Thursday, Mark and Doug spotted a recent slab avalanche (photo) that occurred near Skyline Ridge in the southern Madison Range. This is a good example of where avalanches can be triggered: slopes steeper than 35 degrees in areas with a relatively thin snowpack. Recent large slides near Cooke City have been triggered in similar terrain (video).
The odds of triggering a large avalanche on facets near the ground are low but the consequences are high. The best way to avoid a deep slab avalanche is to manage terrain carefully. Choose slopes less than 35 degrees in steepness and avoid rocky areas where the snowpack is shallow and weak.
Today, human triggered avalanches are possible on slopes steeper than 35 degrees where the avalanche danger is rated MODERATE. Avalanches are unlikely on less steep slopes which have a LOW avalanche danger.
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.
UPPER HYALITE ROAD CLOSURE
Beginning today, the Hyalite road beyond the dam will be closed to motorized use. The Hyalite Road from the mouth of the canyon to the Blackmore Day Use site remains open. Read more in this press release.
ACCIDENT REPORTS
10 March, Altoona Lakes Fatality (by West Central Montana Avalanche Center)
11 March, Crown Butte Fatality
15 March, Mount Abundance Injury
BLOG POSTS
Check out our latest Blog Posts. Mark wrote about the deep slab avalanche problem. Eric wrote an article about what it takes to put out an avalanche forecast and Doug recapped some lessons from the Beehive avalanche incident in February that was published in Carve.