Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, February 22, at 7:15 AM. Today’s advisory is sponsored by Yellowstone Ski Tours and Bridger Bowl. This advisory does not apply to operating ski areas.
Over the past 24 hours no new snow has fallen. This morning, skies are mostly cloudy and temperatures range from the mid-teens to low 20s F. Winds are blowing 10-25 mph out of the W-NW with a few ridgetop gusts breaking 30 mph. Today, there is the chance of mountain snow showers with 1-2 inches possible. Highs will climb into the mid-20s to low 30s F and winds will continue to blow 15-25 out of the W-NW. A slight chance of mountain snow continues into the evening, but tomorrow looks to be sunny and nice.
Southern Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone Cooke City
Avalanches continue to be triggered on buried surface hoar in the southern ranges (photo page). Yesterday, a snowmobiler in the Lionhead area near West Yellowstone triggered a slide on a north facing slope that broke 1-2 feet deep (photo). Skiers in Bacon Rind in the southern Madison Range also found surface hoar buried 20-40 cm under the surface which produced unstable results in stability tests.
This problem has been most active on north and east facing slopes, but I wouldn’t rule it out on sunnier aspects. The tricky part about buried surface hoar is it typically has spotty distribution. This can make stability assessment complicated. Under these types of conditions it’s always worth evaluating terrain and snowpack carefully before committing to steeper slopes. This usually means pulling out a shovel and digging a quick snowpit to assess this layer of concern. It only takes a few minutes and if buried surface hoar is present it will likely appear as a gray stipe in the snow (photo).
As days go by without new snow or wind loading, this layer will become less active. This does not mean that conditions are less dangerous. It’s still likely that skiers and riders will trigger avalanches on steeper slopes where this layer is present.
For this reason, the avalanche danger is rated CONSIDERABLE on slopes steeper than 35 degrees. Less steep slopes have a MODERATE avalanche danger.
Bridger Range Northern Madison Range
Northern Gallatin Range
Yesterday Alex and I did a long tour around Hyalite in the northern Gallatin Range. We found a wide variety of snow conditions ranging from stout ice crusts to soft powder. What we didn’t find was recent avalanche activity and unstable conditions. We both felt comfortable skiing in avalanche terrain and ventured onto slopes we wouldn’t have set foot on a month ago. This is a good indication the snowpack is getting stronger.
Without a recent loading event or a freshly buried weak layer, it is becoming increasingly difficult to trigger an avalanche. This however does not mean it’s time to throw caution the wind. Unstable snow may exist on isolated terrain features and standard backcountry protocol still applies.
Today, small avalanches in isolated areas or extreme terrain remain possible, but generally safe avalanche conditions exist and the avalanche danger is rated LOW.
Doug 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, February 24, 6-7 p.m. 1-hr Avalanche Awareness, Roskie Hall, MSU.