Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, March 15, at 7:00 AM. Today’s advisory is sponsored by Community Food Co-op and Cooke City Super 8/Bearclaw Bob’s. This advisory does not apply to operating ski areas.
In the last 24 hours the mountains picked up 1-2” of new snow with Cooke City getting 3”. Winds have been steady out of the west at 15-20 mph with gusts of 30 mph. Under cloudy skies mountain temperatures are 10F this morning. Today will remain cloudy as a moist northwest flow brings snow showers and 20-30 mph winds from the W-NW with temperatures in the low 20s. By tomorrow morning I expect 2-3” of new snow.
Southern Madison Range Southern Gallatin Range
Lionhead area near West Yellowstone
The mountains south of Big Sky to West Yellowstone had snowfall six of the last seven days. This totals over two feet of dense snow measuring 2.5-3” of SWE. Strong westerly winds loaded slopes even more. The snowpack is harboring a few weak layers buried 2-4 feet deep: one is surface hoar and another is small-grained facets. Eric and his partner triggered a couple avalanches on small wind-loaded slopes on Sunday in Taylor Fork (video, photo). Small avalanches that are easily triggered are serious warning signs that bigger slopes are also unstable. Since Eric’s visit these mountains have gotten another foot of snow and strong winds. Yesterday, snowmobilers noted collapsing and cracking and saw natural avalanches in the Centennial Range west of Lionhead (3 photos). This area is outside our forecast area, but the observations are relevant because I expect the snowpack to be similar.
Given all the new snow, wind, avalanches and more snow forecasted today, the avalanche danger is rated CONSIDERABLE on all slopes since human triggered slides are likely.
Bridger Range Northern Madison Range
Northern Gallatin Range Cooke City
The northern mountains, as well as Cooke City, have gotten half the snowfall as West Yellowstone over the last week (1.2-1.8” SWE). They have not been spared the strong west winds and wind-loaded slopes are our main avalanche concern. Yesterday, the Bridger and Big Sky Ski Patrols were able to trigger avalanches with ski cuts and explosives in the storm snow. Cooke City remains eerily quiet with no reports of avalanches in the last few days, but I would bet a rider or skier could trigger a wind-loaded slope without much effort.
Today, the avalanche danger is rated CONSIDERABLE on all wind-loaded slopes and MODERATE on all other terrain.
I will issue the next advisory tomorrow morning by 7:30 a.m. If you have any snowpack or avalanche observations to share, drop us a line at mtavalanche@gmail.com or leave a message at 587-6984.