Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Thursday, March 30th at 7:00 a.m. Today’s advisory is sponsored by Gallatin County Search and Rescue and Montana Ale Works. This advisory does not apply to operating ski areas.
At 5 a.m. it’s raining in the valley and snowing in the mountains. Snow level is currently around 7,000 feet. Overnight, the mountains south of Bozeman picked up 4-6” of new snow while Bridger Range and northern Gallatin Range picked up 3-4”. This morning, temps range from the upper 20s to low 30s F and winds are blowing 5-15 mph out of the W-SW. Today, temps will only warm a few degrees and winds will remain light to moderate out of the W-SW. Snow will continue across the advisory area favoring the mountains south of Bozeman. By tomorrow morning the southern ranges including Big Sky will see an additional 4-6” of new snow while the mountains around Bozeman will see 2-4”.
The current weather pattern will create a variety of avalanche problems today. On mid to low elevation slopes, above freezing temps and rain will increase the wet snow avalanche hazard. The thick surface crust that formed the past few days will hold up this morning, but the snowpack will become soft and unsupportable as the day progresses, mainly on slopes below 8,000 ft. This problem will be most dangerous in steep terrain, primarily in areas associated with terrain traps such as creek beds and gullies.
On upper elevation slopes, the dry snow avalanche hazard will increase as snow continues to fall. Dry loose avalanches in steep terrain will be the main concern. The firm crust below the new snow will make a good surface for the new snow to slide on (photo, photo). These slides have the potential to entrain a large volume of snow, which can carry a skier or rider into hazardous terrain.
Wind slabs below upper elevation ridgelines will also be a concern. Winds blew 20-30 mph out of the W-SW yesterday, which likely loaded leeward slopes. A recent avalanche outside of Cooke City is a good example of what’s still possible in steep, wind loaded terrain (photo).
Today, the dry snow avalanche hazard will start out MODERATE, but rise to CONSIDERABLE with continued snowfall. The wet snow avalanche hazard on mid to low elevation slopes is MODERATE.
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