This is Ian Hoyer with the avalanche forecast for Saturday, December 14th at 7:00 am. This information is sponsored by the Avalanche Alliance and Idaho State Snowmobile Association - Avalanche Fund. This forecast does not apply to operating ski areas.
This morning, there is one inch of new snow around Cooke City and none elsewhere. Winds are 20-30 mph out of the southwest, with gusts of 40-50 mph (a bit lighter around Cooke City). Temperatures are in the teens and 20s F.
Snow will start falling this morning around Island Park and West Yellowstone, spreading across the advisory area tonight. By tomorrow morning, expect:
Island Park: 10-14” new snow
Lionhead: 6-10” new snow
Everywhere else: 3-5” new snow
Winds will remain strong and southwesterly, with temperatures rising into the 20s and low 30s F today.
Wind Slab avalanches are the primary concern today. Winds picked up again last night and drifting was observed yesterday (Blackmore, Lick Creek, Beehive), so there will be fresh wind drifts that could avalanche today. There are also older drifts that have now bonded and are no longer an issue. Take the time to investigate and figure out what sort of drift you’re dealing with before committing to steep wind-loaded slopes.
Stay tuned over the coming days, as Persistent Slab avalanches will likely become an issue as the widespread weak layers get loaded by new snow (Blackmore video, Cooke City photo).
The avalanche danger is MODERATE.
It’s going to start snowing in Island Park this morning and there could be 4-8” of new snow by sunset. With strong winds, this new snow will quickly drift into slabs deep enough to be problematic. These wind drifts will build on top of weak layers just below the old snow surface, so these Wind Slab avalanches will be especially reactive (video).
The avalanche danger will quickly rise to MODERATE as it starts snowing this morning.
Snow flurries today may deposit a couple inches of new snow, but it shouldn’t be enough to increase the avalanche danger. There is plenty of weak snow (Taylor Fork surface hoar video), but in most places there isn’t enough of a slab on top to avalanche. Watch out for the isolated places where there are deeper drifts and an avalanche might be possible. If the snow comes in earlier and heavier than expected, the avalanche danger will quickly rise.
For today, the avalanche danger is LOW.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
Thursday, Dec 19 and Saturday, Dec 21, Companion Rescue Clinic at REI in Bozeman and History Rock. 6 to 8 pm on Thursday, 10 to 2 pm on Saturday.
This Friday, Saturday, or Sunday - Take an intro class with a field day. Register for our Avalanche Fundamentals course.
Friends of the Avalanche Center: Fall Fundraiser!
We’re still counting on your support and the online Fall Powder Blast fundraiser is 79% of the way to our goal. Please consider making even a small donation HERE or via Venmo