Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, March 19 at 7:30 a.m. Montana Import Group in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas.
Last night four inches of new snow fell in the northern Gallatin Range with 1-2 inches covering the rest of our area. Winds are averaging 20-25 mph out of the west with gusts hitting 50 mph. This morning mountain temperatures are near 10F, but will warm into the upper 20s by this afternoon. Today will be dry and sunny with winds tapering off. There’s no snow expected in the next 24 hours, but we are poised to get moisture later tomorrow. Moisture is code for “it might be rain”.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
Some days avalanche forecasting is difficult, other days it’s easy. Today is an easy one. Strong ridgetop winds have created wind slabs, which is our main avalanche problem. These wind-blown, soft slabs of snow do not extend far down the slope and any avalanches will likely be small, shallow and confined to the ridgelines. The danger lies not in the size of the slide, but in the nasty ride over cliffs, into gulleys or against trees.
Other than wind-loaded terrain the snowpack is generally stable and safe. Eric, Andrew the Intern and I went into the Throne area of the northern Bridger Range yesterday. Underneath eight inches of 12% creamy snow, was a supportable melt-freeze ice crust formed during last week’s balmy weather. It can be found on many aspects and elevations. Shaded, somewhat northerly facing slopes lacked a supportable crust, but it didn’t really matter since we could not get any layers to propagate fractures in our stability tests, crust or not. We all agreed that triggering a slide would require a spate of bad luck involving, steep, rocky terrain covered by a thin, faceted snowpack. This isolated, yet problematic combination applies to our entire advisory area.
For today the avalanche danger is rated MODERATE on all wind-loaded terrain. Slopes without a wind-load have a LOW avalanche danger.
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.
A climber died in an avalanche in Colorado
A climber in Rocky Mountain National Park died in an avalanche yesterday (story here). US avalanche fatalities now total 15 (stats here). Montana has been spared thus far and my fingers are crossed for the remainder of the season.