Good Morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Thursday, April 3 at 7:30 a.m. Montana Ale Works, in partnership with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas.
Yesterday 2-4 inches of snow fell in most areas except the Bridger Range which got dusted. This morning temperatures were in the teens F and light winds were blowing 10-15 mph from the WNW. Skies should be mostly sunny today. Winds will shift to the W and blow 5-10 mph and high temperatures will be near freezing.
Bridger Range Gallatin Range Madison Range
Cooke City Lionhead area near West Yellowstone
Yesterday, skiers just north of Big Sky triggered several small avalanches about 6 inches deep and 20 feet wide. These slides were breaking on a layer of surface hoar that formed Monday night and is now buried by recent snow about 6-8 inches deep. Heavy snow, that fell late last week and last weekend, also created avalanches, one near Frazier Basin in the northern Bridgers on Sunday, another on Monday near Beehive and Middle Basins north of Big Sky that slid on an ice crust (photo), and one south of Cooke City on Sunday (photo).
The good news is that these shallow instabilities can be quickly and easily assessed. Most stabilize after just a few days, but buried surface hoar may be a longer lasting problem. Deeper and larger avalanches are still possible given the heavy load of snow that fell last weekend (seven day SWE totals of 2-3 inches). A large natural avalanche occurred last Saturday on Mt. Blackmore in Hyalite Canyon (photo). There were many large slides like this in the first two weeks of March and similar activity has slowly tapered off. While the odds of such slides have gone down a lot, they haven’t gone away especially with the stress of last weekend’s heavy snow.
With instabilities in the new snow and a slight chance of avalanches breaking near the ground, today the avalanche danger is rated MODERATE.
Cornices: Cornices are growing at a fast rate and are getting quite enormous this season. They can break with a passing skier and deserve a wide berth. A falling cornice can also be a very good trigger for deep slab avalanches.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
Our last daily avalanche advisory will be this Sunday, April 6th. If conditions warrant we will issue intermittent advisories the following week.