Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Saturday, March 18th at 6:00 a.m. Today’s advisory is sponsored by Yellowstone Arctic Yamaha and Yamaha Motor Corp in partnership with the Friends of the Avalanche Center. This advisory does not apply to operating ski areas.
No new snow fell over the past 24 hours. This morning, temperatures are in the mid to upper 30S F under mostly clear skies. Winds are blowing 10-25 mph out of the W-SW with ridgetop gusts breaking 30 mph. Today, the existing ridge of high pressure will remain over the area allowing temperatures to reach near record highs. Winds will remain light to moderate out of the W-SW and skies will remain mostly clear. The ridge begins to break down later today increasing the chance of clouds and stronger winds. Precipitation develops over the mountains tonight. The southern ranges could see 1-3” of snow above 7,000 ft. by tomorrow morning.
Temperatures did not drop below freezing last night. However, clear skies allowed for radiational cooling, which will firm up the snow surface. This will eliminate the wet snow avalanche hazard during the early morning hours.
The surface crust will break down quickly under the influence of sun and warming temps. By late morning-early afternoon, wet loose avalanches will be a concern on all but north facing slopes. Pay close attention to changing conditions and avoid steeper terrain where pinwheels and small point releases are present (photo). If you plan to ride in avalanche terrain today, I advise an early start and an early finish.
Today, the wet snow avalanche danger will start out LOW, but rise to CONSIDERABLE by this afternoon.
Note: Cornices have grown weak with the warmer weather (photo). They can break easily with human triggers or fail naturally. These monsters can break farther back than you might expect, so give them a wide berth along the ridgelines and avoid slopes directly below them.
Alex 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.