Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Wednesday, March 22nd at 6:30 a.m. Today’s advisory is sponsored by Alpine Orthopedics and Mystery Ranch. This advisory does not apply to operating ski areas.
At 3 a.m. rainfall started in the valleys and snow began falling in the mountains. At 6 a.m. the northern ranges have up to 1” of wet snow and the southern mountains have 2”. Winds increased from the southwest and are averaging 15-20 mph with gusts of 45 mph. Snow showers will end by 8 a.m. and sunshine will increase throughout the day as mountain temperatures warm into the 40s. Skies will be partly cloudy tonight and freezing levels will drop to near 6,000 feet.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
Wet avalanches will occur today.
Temperatures will rise and the sun will shine, warming and melting the snow. A thick and supportable ice crust 6-12” deep is a perfect sliding surface for the wet snow (photo). Expect natural, point release avalanches on slopes getting baked by the sun. Wet avalanches will be easy to trigger. Signs that the snow surface is weakening and getting close to avalanching are roller balls (photo) and pinwheels. Yesterday, Eric and I toured north of Bridger Bowl to Texas Meadow where I triggered a large pinwheel on the ice crust (photo). At lower elevations there is no crust and the snowpack is wet, unsupportable and prone to avalanching.
Yesterday was warm and the low lying clouds created a greenhouse effect which trapped the heat and warmed the snow more than normal. Even outside Cooke City, our winter hold-out, a ski guide reported moist snow on all aspects up to 11,000 feet. Yesterday’s video from the Bridger Range and Monday’s video from Taylor Fork, show the wet avalanche potential for the coming days.
For today, the wet snow avalanche danger will rise from MODERATE in the morning to CONSIDERABLE as the day heats up, especially on sun exposed slopes.
If you can find dry snow at higher elevations the danger will be MODERATE since avalanches are possible, especially with the recent snow and wind.
CORNICE DANGER
Cornices are extra big this year (photo) and the warm temperatures will weaken their grip on the ridgelines. They can break far from the edge and can trigger large avalanches like this one observed last week in the Bridger Range (photo).
Eric will issue the next advisory tomorrow morning by 7:30 a.m.
We rely on your field observations. Send us an email with simple weather and snowpack information along the lines of what you might share with your friends: How much new snow? Was the skiing/riding any good? Did you see any avalanches or signs of instability? Was snow blowing at the ridgelines? If you have snowpit or test data we'll take that too, but this core info is super helpful! Email us at mtavalanche@gmail.com or leave a message at 406-587-6984.