Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Thursday, April 4 at 7:30 a.m. Cooke City Motorsports and Yamaha in partnership with the Friends of the Avalanche Center sponsor today’s advisory. This advisory does not apply to operating ski areas.
Yesterday high temperatures were in the 40s F and this morning low temperatures hovered around freezing. Winds were blowing 5-10 mph and gusting to 15 mph from the WSW. Today will have warmer temperatures than yesterday with highs reaching 50 degrees F or higher. Winds will blow 10-15 from the W but increase some this afternoon and shift to the SW. There will be plenty of sunshine today and a few clouds. More clouds will arrive late this afternoon and deliver a trace of precipitation by tomorrow morning.
Bridger Range Madison Range Gallatin Range
Lionhead area near West Yellowstone Cooke City
For the last three days the snowpack has become warmer and wetter each day. Warm skies at night, which prevent radiational cooling, and low temperatures that barely reach 32 F have not been able to refreeze the snowpack enough to stabilize it. Wet avalanches occurred everyday this week at and near Big Sky (photos 1, 2, 3). Some have been wet slab avalanches.
A very thin layer of snow at the surface is frozen this morning. This thin crust should melt quickly and stability will rapidly deteriorate because the snow underneath did not freeze and remains weak and wet.
The best places to ski and ride today are north facing slopes at the highest elevations with dry snow. To get there and back, avoid avalanche runout zones especially if you see any pinwheels of snow rolling downhill. With more wet avalanches expected today, the avalanche danger is rated CONSIDERABLE.
Changing weather and changing avalanche problems: Wet avalanches have been the main concern this week, and indications of this problem are pinwheels, sinking past your boot tops, and other signs the snow is heating up. This weekend may have colder temperatures, new snow, and wind. In this case we’ll need to give the new snow time (maybe 12-24 hours) to bond to any ice crust on which it falls. Watch for cracking and any fresh wind slabs. Regardless of the avalanche problem, always look carefully for recent avalanches, wet or dry, as these are the number one sign of unstable snow.
Doug 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.
Take Note:
Our 136th and last avalanche advisory will be on Sunday, April 7th.