Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, April 4, at 7:30 a.m. Montana Ale Works, in cooperation with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas.
Over the past 24 hours intermittent snow squalls dropped 2-3 inches of snow on the Bridger and Northern Gallatin ranges and 1-2 inches on the mountains around Big Sky and Cooke City. The mountains West Yellowstone have remained dry. Currently, mountain temperatures are in the single digits F around Big Sky and low to mid teens elsewhere and will climb into the 30’s F by this afternoon. Winds are blowing 15-25 mph out of the W, but will increase into the 30’s with gusts into the 40’s by this evening. Today, a brief ridge of high pressure will produce mostly sunny skies during the morning hours, but increasing clouds will move into southwest Montana by this evening. Another storm is forecasted to impact our area tonight into tomorrow. 2-3 inches of snow is possible in the mountains by tomorrow morning.
The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range
After a spell of spring weather, with temperatures in the forties, lightning, thunder and rain - yesterday's below zero wind chill was a brisk reminder that winter's grasp has not fully released. Combined with below average temperatures, 4-6 inches of low density snow made for some adventurous dust on crust conditions. Aside from low density snow's inability to cover petrified tracks and frozen roller balls, it poses a few other concerns. First, low density snow is easily moved by the wind, which can produce sensitive wind slabs in a short amount of time. Second, light snow easily sluffs on steep slopes, producing fast moving piles of snow that could potentially push a skier or rider into unfavorable terrain.
Today, winds are forecasted to pick up out of the west, which will further develop slabs and drifts on leeward slopes. East facing, upper elevation slopes, specifically near ridgelines will be the most likely areas to find sensitive conditions. Strong winds may also cross load mid-elevation slopes, which could become a growing problem throughout the day. The good news is – avoid wind loaded terrain and you will mostly avoid avalanches.
Today, heightened avalanche conditions exist on wind loaded slopes where the avalanche danger is rated MODERATE. Slopes that have not received a wind load have a LOW avalanche danger. If the winds continue to crank throughout the day, the avalanche danger could rise to CONSIDERABLE on wind loaded slopes.
Wet Snow Avalanche Danger
The wet snow avalanche danger today will depend on cloud cover and wind. If the sun shines unimpeded into the afternoon, south and west facing slopes could warm to the point of producing wet loose avalanches. These slides should remain fairly small, but could potentially carry a skier or rider into terrain traps or over rocks and cliffs. Roller balls and small point releases are tell tales signs the surface snow is becoming unstable.
Doug 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.
Last Advisory
The last avalanche advisory of the winter is Sunday, April 10th. That will be our 145th advisory of the season—more than any other in our 21 year history.