Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Monday, March 30th, at 7:30 a.m. Team Bozeman in cooperation with the Friends of the Avalanche Center sponsor today’s advisory. This advisory does not apply to operating ski areas.
Old man winter is still flexing his muscles. In the last 24 hours 9-12 inches fell in the Bridgers and northern Gallatins, 14 inches in the mountains around Big Sky, four inches near West Yellowstone and seven inches around Cooke City. Storm totals measure 14-17 inches in the northern mountains and 20-24 inches in the southern mountains including Big Sky. Winds have picked up and are blowing north to northwest at 20 mph with gusts in the 30s as temperatures dropped to the single digits at 9,000 feet. Under mostly cloudy skies, winds will continue, temperatures will increase into the high teens and we could get dusted with another inch of snow tonight.
The Bridger, Gallatin and Madison Ranges, and the Lionhead area near West Yellowstone: Today isn’t a real brain teaser when it comes to the avalanche danger. It’s going to be bad out there for a few simple reasons. It snowed. A lot. And it was windy too. And if that isn’t bad enough, it fell onto a snowpack that was avalanching BEFORE this storm. Last week natural and human triggered avalanche activity in the Bridgers, northern Gallatins and Madisons all ran on a layer of faceted snow two feet off the ground. This new snow has put an additional burden on the snowpack and I expect to see natural avalanches as this layer fractures. During the storm the air temperatures dropped creating light weight powder. It also became windier and formed drifts which the ski patrols easily triggered. Soft slab avalanches one to two feet deep ran far. In the backcountry I expect these wind slabs to be reactive and possibly break down into the faceted snow. Today will be a day to trigger avalanches. Maybe it’ll be confined to the new wind blown snow, or perhaps it’ll break deeper. Either way is bad news if you get caught. With upwards of two feet of new snow, strong winds and a known weak layer buried deeply in the snowpack, notch back your ambitions. Triggering an avalanche is likely today. The avalanche danger is rated HIGH on all wi<p>The Bridger, Gallatin and Madison Ranges, and the Lionhead area near West Yellowstone:
Today isn’t a real brain teaser when it comes to the avalanche danger. It’s going to be bad out there for a few simple reasons. It snowed. A lot. And it was windy too. And if that isn’t bad enough, it fell onto a snowpack that was avalanching BEFORE this storm. Last week natural and human triggered avalanche activity in the Bridgers, northern Gallatins and Madisons all ran on a layer of faceted snow two feet off the ground. This new snow has put an additional burden on the snowpack and I expect to see natural avalanches as this layer fractures.
During the storm the air temperatures dropped creating light weight powder. It also became windier and formed drifts which the ski patrols easily triggered. Soft slab avalanches one to two feet deep ran far. In the backcountry I expect these wind slabs to be reactive and possibly break down into the faceted snow. Today will be a day to trigger avalanches. Maybe it’ll be confined to the new wind blown snow, or perhaps it’ll break deeper. Either way is bad news if you get caught.
With upwards of two feet of new snow, strong winds and a known weak layer buried deeply in the snowpack, notch back your ambitions. Triggering an avalanche is likely today. The avalanche danger is rated HIGH on all wind-loaded terrain as well as on any slope steeper than 35 degrees. All other terrain will have a CONSIDERABLE danger.
The mountains around Cooke City and the Washburn Range:
The mountains around Cooke City received 20 inches of snow with strong northerly winds. Our primary avalanche concern is going to on wind-loaded slopes where natural avalanches will be visible and you’ll likely trigger a slide. Most of the terrain above treeline is wind-effected and should be approached with utmost caution. Today is a day to boondock with your sled or ski in the trees. A lot of new snow has fallen and the snowpack is the most unstable during and immediately after a big storm. Consequently, the avalanche danger is rated HIGH on all wind-loaded terrain. On slopes not effected by the wind the danger is CONSIDERABLE on slopes steeper than 35 degrees and MODERATE on lower angled slopes.
SKI CUTTING
I hear about folks ski cutting slopes all the time as if it’s a standard, safe and easy practice. This is not true. Many, many skiers get caught in avalanches while ski cutting. They think they’re being safe, when in fact they’re not. Ski cutting has a very narrow window of use on new snow if it’s done perfectly. It’s a great tool for ski patrols since they deal mostly with storm snow and have explosives to back them up. In the backcountry we have weak layers buried deep in our snowpack which makes ski cutting ineffective and potentially dangerous. You’ll get caught in an avalanche if the slab you’re cutting is too thick, if the slope is too wide, if you get too far into the starting zone, if you zig-zag and if you go too slowly. Quite frankly, it’s a high stakes, expert only move.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or send us an email with your observations. You can reach us at 587-6984 or at mtavalanche@gmail.com.</p>