This is Ian Hoyer with the avalanche forecast for Friday, February 7th, at 7:00 a.m. sponsored by the Gallatin County Sheriff Search and Rescue and Idaho State Snowmobile Association - Avalanche Fund. This forecast does not apply to operating ski areas.
This morning, it’s snowing and 2-3” of new snow have accumulated so far. Winds are blowing from basically every direction on the southern half of the compass (W-SE in most areas and straight E in the Bridgers) at 15-30 mph with 25-50 mph gusts. Temperatures are generally in the teens F.
Winds will increase this morning, shifting to be consistently out of the west. High temperatures will be in the 20s F in the southern areas, but will stay steady or actually fall throughout the day in the areas around Bozeman and Big Sky. Steady snowfall, which may be heavy at times, will add up to 4-8” in most places by this evening. Cooke City will be a bit favored and may get more like 6-10”. Snowfall will end this evening.
All Regions
It’s been a wild week of unusual weather - with hurricane force winds, winds blowing from unusual directions, both very warm and very cold temperatures (sometimes right next to each other with crazy strong temperature inversions), and periods of rapid snowfall. This all came after some new weak layers formed and it has left us with quite a variable snowpack.
Now it’s snowing again. This will both add load to the snowpack and make it harder to visually identify what’s been going at the snow surface over the last week (Dave’s video from Blackmore yesterday).
Unusual weather leads to unusual avalanches. This has certainly been the case over the last couple days.
- On Wednesday, Big Sky Ski Patrol intentionally triggered an avalanche with explosives on a slope loaded by the strong south winds that broke up to 7 feet deep, breaking on the old snow surface from dry weather in late January. They haven’t seen an avalanche like that on that slope in 40-50 years. (photo, news story
- Also on Wednesday, skiers triggered many storm slab avalanches in the new snow at low elevations on Mt. Ellis and in the Bridger Range.
- There have also been plenty more typical avalanches on wind-loaded slopes below ridgelines across the advisory area (examples from near Cooke City (1, 2, 3, 4), Lionhead, and the Bridgers).
Very strong winds and winds from unusual directions (out of the east) have loaded slopes that aren’t usually loaded, so be on alert for wind loading everywhere. Additionally, be on alert for slides on lower elevation slopes that usually aren’t much of a concern. In some cases, with the strong inversions mid-week, they may have touchier conditions than higher elevation slopes (observation).
With lots going on in the snowpack and it being loaded again, avalanche conditions are dangerous and cautious route-finding is required. Avalanches could break as Wind Slabs either in the new snow or from snow drifted earlier in the week, Storm Slabs as snow piles up during intense precipitation today, or Persistent Slabs on the weak layers that formed during the dry period in late January.
Today, the avalanche danger is CONSIDERABLE.
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
February 20, 4-7 p.m. Beacon BBQ at Uphill Pursuits in Bozeman. Come try out different brands of avalanche transceivers (or practice with your own!) with coaching from Friends of GNFAC instructors and free hotdogs.
Every weekend in Cooke City: Friday at The Antlers at 7 p.m., Free Avalanche Awareness and Current Conditions talk, and Saturday from 10 a.m.-2 p.m. at Round Lake Warming Hut, Free Rescue Practice.