Good morning. This is Alex Marienthal with the Gallatin National Forest Avalanche Advisory issued on Saturday, March 5, at 7:00 AM. 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.
The mountains did not receive any new snow in the last 24 hours. Temperatures are in the high 20s to low 30s F this morning. Winds overnight were out of the south-southwest at 10-20 mph with gusts over 40 mph in Hyalite and Big Sky. Today will be partly sunny with increased cloud cover this afternoon. Temperatures will be in the 40s F and wind will be out of the southwest at 25-35 mph. Isolated snow showers tonight will deliver a trace of snow to the southern mountains with more accumulation throughout the area tomorrow afternoon.
Southern Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone Cooke City
The primary avalanche concern in the southern mountains is a layer of surface hoar buried 1-3 feet deep. Doug had unstable test results on this layer on Wednesday at Bacon Rind (video, photo), and Eric found similar results on this layer yesterday in Cabin Creek (video). Avalanches on this surface hoar layer have become less likely, but its presence makes avalanches possible. This layer does not exist on every slope, which can make stability assessment tricky. It has mostly been observed on shady, east to north facing slopes, but can’t be ruled off any slope until you dig a couple pits to confirm it is not there. Identify this layer as a stripe in the snowpit wall (photo), and avoid steep slopes where it exists.
Above freezing temperatures today will make wet loose avalanches possible on sunny slopes. Increased cloud cover this afternoon may limit this activity, but watch for changing surface conditions and avoid steep slopes where the snow surface is wet or large roller balls form.
Avalanches on buried facets or depth hoar are unlikely. However, these weak layers exist on many slopes and could produce avalanches in isolated areas or extreme terrain.
It will be possible to trigger avalanches on buried surface hoar today and wet loose avalanches are possible this afternoon. For today, the avalanche danger is rated MODERATE.
Bridger Range Northern Madison Range Northern Gallatin Range
The mountains in the northern half of our advisory area have a relatively stable snowpack. Some slopes contain weak snow and a poor snowpack structure, but they have not been stressed by heavy loads since late January. It is unlikely to trigger an avalanche, but not impossible. Continue to practice safe travel, consider the consequences of terrain, and dig snowpits to confirm the snowpack is what you expect. Today, the avalanche danger is rated LOW.
Above freezing temperatures today will make wet loose avalanches possible and may increase danger to MODERATE this afternoon. Wet loose avalanches are possible on sunny slopes where the snow surface is unconsolidated and where crusts become soft and wet. Watch for changing surface conditions and avoid steep slopes where the snow surface is wet or roller balls form.
Eric 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, March 9, 6-7 p.m. 1-hr Avalanche Awareness, REI.