Good Morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Saturday, April 5 at 7:30 a.m. This advisory is dedicated to the ski patrollers at Bridger, Big Sky, and the Yellowstone Club who provide daily avalanche observations and weather data which are crucial pieces of information for each day's adivisory. Because of their hard work, this advisory does not apply to operating ski areas.
Last night 1-3 inches of snow fell throughout the advisory area. This morning temperatures were in the low-mid 20s F. Westerly winds blew a bit stronger overnight but eased some this morning and were blowing 10 mph gusting 15-20 mph. More clouds and some moisture will come today. High temperatures will be near freezing. Light winds will blow 5 mph gusting 15 mph from the W and may increase again this afternoon. Another 1-3 inches of snow should fall with more snow coming from the NW on Sunday.
Bridger Range Gallatin Range Madison Range
Cooke City Lionhead area near West Yellowstone
Yesterday morning the Big Sky Ski Patrol found fresh wind slabs on high elevation north facing terrain that were very sensitive to ski cuts. Similar wind slabs should exist in the backcountry this morning. Also on north facing terrain near treeline, surface hoar was found buried about 1 foot deep near Beehive Basin (photo before it was buried). In the northern Bridger Range pockets of buried graupel were seen on Thursday (photo). These should have bonded by now and shallow wind slabs will be the main concern.
For today, watch out for wind slabs and areas with instabilities in the upper foot of the snowpack. With some new snow overnight avalanches remain possilble on slopes steeper than 35 degrees where the danger is rated MODERATE. Avalanches are unlikely on less steep slopes where the danger is LOW.
Cornices: Cornices are growing at a fast rate and are getting quite enormous this season. They can break with a passing skier and deserve a wide berth. A falling cornice can also be a very good trigger for deep slab avalanches.
Doug will issue the next and final advisory tomorrow morning at 7:30 a.m. Have a great spring and summer and we'll see you in the fall.