Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Thursday, February 11, at 6:45 AM. Today’s advisory is sponsored by Community Food Co-op and Spark R&D. This advisory does not apply to operating ski areas.
This morning mountain temperatures are in the high 20s with westerly ridgetop winds averaging 20 mph and gusting to 50 mph up Hyalite and 30 mph elsewhere. Skies are mostly cloudy and will remain so as temperatures climb into the low 40s today. It’s spring in February, but do not despair, winter is far from over. I’m an optimist and it looks like we could get snow Saturday afternoon.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
Alex is in Cooke City for two days digging snowpits when he’s not getting his sled unstuck. The snowpack structure in Cooke City is very similar to other ranges. On all slopes there are large grains of depth hoar at the ground and on some others there are additional weak layers in the upper two feet of the snowpack. Strong winds on Saturday loaded slopes causing a couple avalanches to break on the depth hoar (Woody photo, Republic photo). Skiers also triggered a 2-3’deep x 150’ wide wind slab on Sunday and luckily no one was caught.
Throughout southwest Montana slopes are still showing occasional instability in our tests, both on the depth hoar and on the upper facets. Alex opted to not ski a south-facing slope when his tests showed the upper facets breaking clean (photo of pit, photo of slope). Slopes that are greater than 35 degrees, and/or those that were heavily wind-loaded are still suspect. In the last few days there have not been any signs of instability so you should dig and test before entering avalanche terrain. We are trending toward stability, but the poor snow structure of depth hoar underlying our entire snowpack cannot be forgotten, which I outlined in Sunday’s video at Bacon Rind.
For today, the avalanche danger is MODERATE on slopes steeper than 35 degrees and on any slope that was wind-loaded. Lower angled terrain without a wind-load has a LOW danger.
This weekend I was talking with the director of the Colorado Avalanche Information Center. He said that because of deep slab avalanches (depth hoar), 10% of their avalanche occurrences account for 50% of their fatalities. In other words, rarer and larger events kill people. Colorado is no stranger to deep slab avalanches and it would be foolish to discount our own snowpack since they are kissing cousins.
Alex 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.
Darren Johnson Avalanche Education Memorial Fund
The National Avalanche Foundation set up an education fund in memory of Darren Johnson, the Yellowstone Club ski patroller who died in an avalanche on January 19. You can check out details and make donations here: http://www.mtavalanche.com/sites/default/files/NAF%20Darren%20Johnson%20Memorial%20Fund.pdf.
EVENTS and AVALANCHE EDUCATION
A complete calendar of classes can be found HERE.
West Yellowstone: Saturday, February 20, 7-8 p.m., 1-hr Avalanche Awareness for Snowmobilers at the Holiday Inn.