Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, February 23, at 7:15 AM. Today’s advisory is sponsored by Grizzly Outfitters and Cooke City Motorsports. This advisory does not apply to operating ski areas.
Carrot Basin in the southern Madison Range got 2-3 inches of new snow yesterday morning with only a trace falling elsewhere. This morning, under clear skies, mountain temperatures are in the upper single digits with west to north winds averaging 5-15 mph and gusting to 20 mph. Today will be sunny with light winds and mountain temperatures reaching the mid-30s. Tomorrow looks the same, as does Thursday and Friday. Shorts and flip flop sightings are inevitable.
Southern Madison Range Southern Gallatin Range Lionhead area near West Yellowstone Cooke City
The southern half of our advisory area has a layer of buried surface hoar that has been avalanching over the weekend. Skiers and snowmobilers triggered many slides, with the most near Cooke City. Our Photos page was updated again last night and worth a look since it shows the scope of the problem. Around Cooke City this layer is 2-3 feet deep while it is only 1-2 feet deep around Lionhead and in the southern Madison Range.
- Yesterday, I investigated a 3-6 foot deep avalanche on the north side of Scotch Bonnet near Cooke City and made a video at the crown.
- Yesterday, Karl went to Bacon Rind and found a thick layer of surface hoar and made a video of his stability test (ECTP14).
- Numerous avalanches were triggered outside Cooke City on many aspects and elevations.
- Snowmobiler triggered avalanches were reported near Black Bear, at Lionhead and Cabin Creek on Saturday and Sunday.
The buried surface hoar is persistent and will be with us for weeks to come. It is not found on all slopes. There is no easy way to identify where it is located. Many slides are on north to east aspects, but some are on westerly and southerly too. The only way to mitigate the danger is to dig down, look for it and avoid slopes where it exists. Given the variable distribution of this layer along with the fact that it’s still possible to trigger an avalanche, the danger is rated MODERATE on all slopes.
Bridger Range Northern Madison Range Northern Gallatin Range
The northern half of our forecast area is mostly stable and triggering avalanches is unlikely. There are still slopes that have a poor snow structure, as Eric and Karl found on Mt. Ellis last week, but without a heavy load of new snow to put stress on the snowpack slopes will remain weak, but stable. Besides Mt Ellis, Eric and young Alex found stable conditions in the Bridger Range and up Hyalite in the last week. I’m sure there are a few steep slopes that have lingering instabilities where an unlucky person could trigger a slide. Avalanches are not impossible, just improbable right now. Given the lack of snow and mostly stable conditions, the avalanche danger is rated LOW.
I 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.
TOMORROW, Bozeman: Wednesday, February 24, 6-7 p.m. 1-hr Avalanche Awareness, Roskie Hall, MSU.