Good Morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Friday, March 26, at 7:30 a.m. The Moonlight Basin Ski Patrol, in cooperation with the Friends of the Avalanche Center, sponsors today's advisory. This advisory does not apply to operating ski areas.
Today will be a good one to call in sick to work. Since yesterday the Bridger Range and northern Madison Range received 8-9 inches of snow. The southern Madison Range and the mountains around Cooke City and West Yellowstone received 6 inches of snow, and the northern Gallatin Range received 2 inches. This morning temperatures were in the high teens and low 20s F, and winds were blowing 15-30 mph from the W with a few gusts reaching 40 mph. Heavy snowfall has ended, but light snow will continue sporadically through today and tonight with an additional 1-2 inches falling by tomorrow morning. Temperatures will reach the mid 30s F and winds will blow 20-25 mph from the W and NW.
The Bridger Range:
Overnight the Bridger Range received 8-9 inches of heavy snow containing over 1 inch of water bringing the total to 3 inches of water during the past seven days. In mid February a similar amount of snow fell over 48 hours and very large avalanches occurred including one on Saddle Peak. Today the primary avalanche concern is a layer of facets near an ice crust that was buried a week ago. Several human triggered avalanches occurred on this layer prior to last night's storm (photo). With more snow and strong winds, I expect more avalanches mostly breaking about 2 feet deep but larger ones are possible and should be considered. Today the avalanche danger is CONSIDERABLE on all wind loaded slopes or any slope steeper than 35 degrees. Less steep slopes without wind-blown snow have a MODERATE avalanche danger.
The Gallatin and Madison Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
The mountains near Big Sky received about the same amount of snow but half the water and half the stress on the snowpack. For this reason the primary concern is any slope with wind-blown snow. During the storm winds started blowing from the SW and shifted to W by this morning. Yesterday afternoon before much snow had fallen, the Moonlight Basin Ski Patrol began finding small wind slabs sensitive to ski cuts. These wind slabs will be larger and more sensitive today. Most avalanche activity will be confined to the storm snow, but deeper avalanches are possible on weak layers buried about 2 feet deep. These weak layers formed on most slopes but are weaker on some than others. Deeper in the snowpack, facets near the ground remain. Avalanches on this layer have become less likely, but its potential to produce large avalanches remains a concern. Today, the avalanche danger is rated CONSIDERABLE on all wind loaded slopes. All other slopes have a MODERATE avalanche danger.
YouTube: Saddle Peak Avalanche Q&A
The Saddle Peak Avalanche Q&A held March 4th at the Bozeman Public Library is now online thanks to the Randy and Kristin Wimberg. The entire 75 minute session can be viewed in two parts. Find it on our Videos Page or here: Part 1, Part 2.
New Beacon Park
The Friends of the Avalanche Center used a donation from Yellowstone Adventures to purchase an avalanche beacon training park in West Yellowstone. You can search for pre-placed beacons switched on/off by a control panel. Look for it by the orange snow fence just south of the old airport (photo).
I will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry let us know what you find. You can reach us at 587-6984 or email us at mtavalanche@gmail.com.