Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Saturday, April 2, at 7:30 a.m. Northern Lights Trading Company, in cooperation with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas.
Mountain temperatures are in the mid to upper 30s F this morning with winds blowing 15-30 mph from the SW. A trough of low pressure will approach Montana this morning and bring significant changes in the weather. Strong SW winds with gusts up to 50 mph should arrive at the front of this system. Snow should arrive in the mountains this afternoon with cold air behind it. Temperatures should rise to the high 30s and low 40s this morning before gradually cooling as the storm progresses. By tomorrow morning 3-5 inches of snow should fall in most areas although the mountains near Cooke City should get a bit more….as they have this entire season.
The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range
Rapidly changing spring weather means rapidly changing avalanche conditions. Heavy snowfall last week (and much of March) caused a few large avalanches on Wednesday and Thursday. Many of these slides were triggered by cornices in steep rocky areas. Several occurred near Sacajawea Peak in the northern Bridger Range (video1, video2), and yesterday I found two large ones on Lionhead near West Yellowstone (photos). A generally strong snowpack allowed significant snow to accumulate on these slopes before producing an avalanche. Other avalanches occurred in the upper foot or two of the snowpack; however, recent warm weather has helped these upper layers bond. BUT, yesterday’s temperatures warmed enough for some wet, loose avalanches to occur on slopes mostly below 8000ft near exposed rock bands.
Keeping track of these changing conditions is tough. Last week - heavy snowfall led to dry snow avalanches. Yesterday afternoon - dry snow avalanches stopped and wet snow avalanches began. Today – with an approaching storm and cooling temperatures, I don’t expect wet snow activity, and dry snow activity will be minimal until more snow arrives. The best riding conditions will be on slopes with a northerly aspect at high elevations where thick wind slabs and drifts may remain sensitive. Although triggering a large avalanche is unlikely, I would prefer a little more time for the snowpack to adjust to recent loading before riding my most ambitious objectives.
With some wet snow, some dry snow, warm temperatures, and even some rain yesterday, conditions are a little funky. Human triggered avalanches are possible today and the avalanche danger is rated MODERATE.
Eric 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.
Ride in honor of Steve Green
TODAY is a memorial ride on Buck Creek Ridge in honor of Steve Green who died in an avalanche last April in McAtee Basin. Meet at 9:30 a.m. at the Buck Creek parking lot near the Corral. Click HERE for more information.
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.