Good Morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Advisory issued on Saturday, March 10th at 7:00 a.m. Today’s advisory is sponsored by Grizzly Outfitters in partnership with The Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
Since yesterday morning the mountains near Cooke City got 4-6” of snow. The mountains south of Bozeman, near Big Sky and West Yellowstone got 1”, and the Bridger Range got less than 1”. Temperatures this morning are single digits to teens F and will warm slowly to 20s and low 30s F this afternoon. Yesterday, wind was southwest at 25-40 mph with gusts of 40-60 mph. Today, wind will be northerly at 5-15 mph. This weekend will be mostly sunny and no snow is expected until later next week.
The mountains near Cooke City got 7-10” of snow over the last three days on top of a 12 foot deep, generally stable snowpack (photo). Clear skies today may be a shock after an extra stormy winter. Wet loose avalanches of new snow are likely where the sun hits steep slopes, and could release naturally around cliffs and steep, rocky terrain (photo). Avoid travel on and below steep, sunny slopes.
Strong wind yesterday drifted recent snow into wind slabs near ridgelines, cross-loaded gullies and steep rollovers. Avoid fresh drifts of snow on steep slopes, especially in terrain where an avalanche has high consequences. Cornices are massive and should be given a lot of space along ridgelines and slopes below.
Wet loose avalanches are likely today and fresh wind slabs are possible to trigger. Avalanche danger is CONSIDERABLE for wet snow avalanches and MODERATE otherwise.
Near Bozeman, Big Sky and West Yellowstone the snowpack is generally stable (video), but small and isolated avalanches can be triggered. A few inches of recent snow, strong wind yesterday, and abundant snowfall all winter create a few hazards to be heads up for.
Strong wind yesterday drifted snow into wind slabs. I was in Beehive Basin and experienced blowing snow all day at all elevations (video). Small wind slabs will quickly stabilize, but deserve caution, especially above consequential terrain.
Abundant snowfall all winter grew massive cornices along ridgelines (photo, video, photo). Give these monsters a lot of space along ridgelines and slopes below. They can weaken and break naturally during spring sun and warm temperatures.
Wet loose avalanches can be triggered on sunny slopes later in the day (photo). Be cautious of travel on and below steep, sunny slopes. Avoid steep slopes if the snow surface is wet, or if you see rollerballs or natural wet avalanches.
Avalanches breaking 2-3’ deep on buried persistent weak layers are not likely, but not ruled out in isolated areas. Eric investigated an avalanche in Red Canyon near Hebgen Lake yesterday. It was triggered by a snowmobiler on Wednesday and broke 2’ deep on a layer of facets on a south facing slope with a shallow snowpack (video). It is always worth digging to assess the snowpack before riding in avalanche terrain.
Small and isolated instabilities exist. Otherwise, the snowpack is generally stable and avalanche danger is LOW.
If you get out and have any avalanche or snowpack observations to share, drop a line via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).
Upcoming Avalanche Education and Events
LIVINGSTON
March 20, Beer for a Cause Night at Katabatic Brewing, 4-8p.m. A dollar from every pint will be donated to The Friends of the Avalanche Center.
In the last 2 weeks there have been 9 avalanche fatalities across the western U.S. This includes two people killed in a roof avalanche in Lake Tahoe. Our snowpack is currently more stable than other areas, but now is no time to let you guard down. See more info on recent accidents here: https://avalanche.org/avalanche-accidents/