GNFAC Avalanche Advisory for Wed Apr 5, 2017

Not the Current Forecast

Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Wednesday, April 5th at 6:30 a.m. Today’s advisory is sponsored by World Boards and Spark R&D. This advisory does not apply to operating ski areas. Bridger Bowl is closed for the season and has the same concerns as the backcountry.

Mountain Weather

Over the past 24 hours no new snow has fallen over the advisory area. At 5 a.m. temperatures are in the 20s under clear skies and winds are blowing 10-20 mph out of the W-NW. Today, a ridge of high pressure will produce partly cloudy skies and warmer temps. Highs today will climb into the upper 30s to low 40s F and winds will remain light to moderate out of the W-SW. No new snow is expected over the next 24 hours.

Snowpack and Avalanche Discussion
Bridger Range Madison Range Gallatin Range Lionhead area near West Yellowstone Cooke City

Spring is an amazing time. You can ski in the morning and golf in the afternoon. Today will be Taylor Made for both activities. Skiing or riding will be best early in the day before sun and warming temps soften the snow surface. On all but due north facing slopes, wet loose avalanches will be the primary problem.

Over the past few days, a few inches of new snow has fallen in upper elevation terrain. This new snow will lose strength and move easily on the firm underlying ice crust as the day warms up. Once the surface snow begins to soften, roller balls and pinwheels are the first sign that wet-loose avalanches can quickly follow. Pay close attention to these obvious clues and manage terrain accordingly. See Doug’s recent video outlining the potential changes to look out for. I don’t expect the firm underlying ice crust to break down today, which will confine activity to the new snow

As folks travel into high alpine terrain the potential exists to trigger dry loose avalanches on steep, shady slopes or find a few rogue wind slabs that could be triggered (photo). Climbers last Saturday triggered a wind slab on the south side of Beehive Peak (photo). This is a good reminder to watch for and respect wind loaded slopes.

For today the wet snow avalanche danger will start out LOW but rise to MODERATE by this afternoon. The dry snow avalanche danger is rated LOW.

I will issue the next advisory tomorrow morning by 7:30 a.m. Our last advisory of the season will be Sunday, April 9th.

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.

MAY 4: Give Big Gallatin Valley

The Friends of the Avalanche Center are one of the recipients of the Give Big Gallatin Valley campaign. It is a 1-day fundraising event for local non-profits on May 4, so mark your calendars. The Friends will send reminders as the day approaches: https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center

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