Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Saturday, March 7th, at 7:30 a.m. The Moonlight Basin Ski Patrol in cooperation with the Friends of the Avalanche Center, sponsor today’s advisory. This advisory does not apply to operating ski areas.
Yesterday an additional 2-4 inches fell in the northern half of the advisory area and 3-5 inches fell in the southern half. This morning under clear skies temperatures were in the single digits F and winds were blowing 10-20 mph from the west. In the Bridger Range winds increased overnight up to 30 mph at all elevations. Today’s weather will be spectacular with mostly sunny skies and temperatures near 20 degrees F. Winds will remain strong and blow 20-25 mph from the west. Clouds will build late this afternoon and 1-2 inches of snow will fall by tomorrow morning with the best chance for snow occuring near West Yellowstone.
The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
Recent snowfall of up to 2-3 ft accompanied by strong winds has added significant stress to the snowpack. Many wind slabs slid naturally and many more waiting for a human trigger. Avalanches several feet deep have been easily triggered by ski patrols using both explosives and ski cuts. Natural avalanches have been seen in the Bridger Range and a human triggered avalanche occurred in the northern part of this range near Fairy Lake on Thursday. This slide occurred as the rider made his first turn and he luckily avoided getting caught. As this avalanche raced downhill it caused an adjacent slope to fracture indicating the sensitive nature of recently buried weak layers. More unstable conditions exist on the west side of the Bridger Range and I would avoid this area.
On Thursday a rider was caught in an avalanche on Buck Ridge near Big Sky when a cornice broke under his feet and he fell onto a wind loaded slope. He was partially buried and uninjured. See photos from this slide at: http://www.mtavalanche.com/photos/photos.php
In the Taylor Fork area on Thursday, my partner and I observed natural avalanches, found very weak snow in our snow pits, and experienced collapsing and cracking of the snowpack. Skiers on Mt Ellis in the Northern Gallatin Range also experienced widespread collapsing of the snowpack on Friday. These are all obvious signs of instability not to be ignored. While wind loaded slopes have produced many recent avalanches, these clues tell us many NON wind loaded slopes are also unstable.
The greatest avalanche concerns today are slides occurring in the storm snow and slides occurring on weak layers buried several feet deep; however, we can not forget about weak facets near the ground. Yesterday the Moonlight Basin Ski Patrol triggered an avalanche on a north facing slope. This avalanche started several feet deep but stepped down producing an avalanche up to 10 ft deep. The weak layer responsible for this avalanche consisted of facets found about 1 ft above the ground.
Because a high degree of variability exists throughout the advisory area, you can find some reasonably stable slopes, but many more unstable slopes exist. Be careful, don’t be fooled, and dig multiple snowpits if you plan on skiing or riding in avalanche terrain today. With significant new snow, strong winds, and recent avalanche activity all wind loaded slopes today have a HIGH avalanche danger. Other slopes have a CONSIDERABLE danger.
UPCOMING EVENTS
Make plans to attend the 28th Annual Pinhead Classic Telemark Festival on March 14th at Bridger Bowl. This year’s theme is “The Olympics” with events for all ages and all abilities. Prizes are awarded for everything but the fastest time and all proceeds benefit the Friends of the Avalanche Center. A registration fee of $30 gets you a ½ -day rate lift ticket, t-shirt, commemorative pint glass, multiple laps on the dual slalom course, numerous prizes and awards, and dinner, dancing, and live music at the Emerson that evening. Visit www.pinheadclassic.com for more information.
NEW DANGER RATINGS
The avalanche danger scale is being revised for next winter. We value your thoughts, so please help with this project by completing a short survey found on the following link:
http://surveys.globalepanel.com/wix/p319164581.aspx
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.
