Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Wednesday, March 7 at 7:30 a.m. Mystery Ranch, in partnership with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas.
Yesterday’s storm dropped 4-6 inches of snow throughout the advisory area except the northern Bridger Range which only received about an inch while only a few miles south, Bridger Bowl received 5 inches. Overnight skies cleared and temperatures dropped to the negative single digits F. Wind speeds and directions have varied considerably. In general winds were blowing strong early yesterday from the SW, calmed midday, then increased last evening from the NW blowing 15-25 mph. In some places like Hyalite winds have been very calm since yesterday while other places like Bridger Bowl and Lionhead they increased overnight. Today will be clear and sunny with temperatures climbing into the low 20s F. Winds will remain varied over the advisory area but will mostly blow from the W and N at 10-15 mph with gusts of 25 mph.
The Bridger, Madison and Gallatin Ranges, the mountains around Cooke City and the Lionhead area near West Yellowstone:
Yesterday’s new snow contained 0.4 inches of snow water equivalent through most of the advisory area. This snow did not provide enough stress to the snowpack to significantly change the danger, but it will keep it from dropping today, and there will be three avalanche problems to address:
- New wind slabs. Strong winds in some areas readily transported yesterday’s snow and formed fresh wind slabs which will easily fracture and avalanche. These wind slabs will be easy to identify and avoid.
- Buried facets. Dig a snowpit about 4 feet deep. If you hit ground and find depth hoar (photo, video), find a different slope with deeper snow. Slopes with deeper snow will have a thin layer of facets buried about 3 feet deep. Assess this layer. It may be relatively strong on some slopes but do not trust it too much because it remains weak on others and can produce avalanches. Recent snowmobile triggered avalanches along Buck Ridge and on Cedar Mountain near Big Sky are good examples. (photo1, photo2, photo3)
- Wet snow. On slopes receiving direct sunshine and little wind, the new snow will warm quickly, and wet point releases should occur today. With temperatures below zero this morning, wet snow avalanches will not be a major problem today but could become a greater problem in coming days.
Wind slabs and wet snow avalanches will be relatively easy to avoid. Avoiding avalanches breaking on buried faceted layers will require digging a snowpit and performing stability tests. These layers will most likely produce avalanches on slopes loaded by either last night’s winds or very strong winds that blew early this week and last weekend. Today the avalanche danger is CONSIDERABLE on all wind-loaded slopes. All other slopes will have a MODERATE avalanche danger.
I 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.
Recent avalanche in Utah
A snowmobiler was caught and buried in an avalanche in Utah on Sunday. He was not wearing a beacon and was buried for about 20 minutes. He was incredibly lucky. Few people buried this long survive. Also, notice a recent avalanche on the adjacent slope. Recent avalanches are clear signs of unstable conditions. http://vimeo.com/38078462
Events/Education
Come to Bridger Bowl on Saturday, March 17th (St. Patrick’s Day) with telemark skis, AT skis, alpine skis, snowboards, split boards, or even snow blades. The theme is Snowpocalypse based on the wildly popular Mayan 2012 apocalypse. $30 gets you into the races, a pint glass, t-shirt, a good time, a raffle ticket, and food by Cafe Fresco. Pre-register at Mystery Ranch or Grizzly Ridge March 11-16. Visit http://pinheadclassic.com/ or the Pinhead Facebook page for more info.
1-hour Avalanche Awareness at REI, Bozeman
Tuesday, March 20 at 6:30 pm. Sign up for this FREE class here.