Good morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Thursday, March 8 at 7:30 a.m. Cooke City Motorsports and Yamaha, in partnership with the Friends of the Avalanche Center, sponsor today’s advisory. This advisory does not apply to operating ski areas.
A ridge of high pressure continues to build over the area and will bring more sun and warmer temperatures today. This morning temperatures were in the low-mid teens F, and westerly winds were averaging 10-15 mph with gusts of 20 mph in most places. They were much calmer further south near Lionhead and the Taylor Fork while further north in the Bridger Range they were blowing 30-35 mph. Today should be noticeably warmer with temperatures near 32 degrees F and westerly winds averaging 10 mph with gusts of 20 mph although stronger winds should continue in the Bridger Range.
The Bridger, Madison and Gallatin Ranges, the mountains around Cooke City and the Lionhead area near West Yellowstone:
Yesterday the Bridger Bowl ski patrol found very sensitive wind slabs (2-14 inches deep) near the ridge that easily released with ski cuts and ran far downhill. These winds slabs were so reactive that the patrol was surprised some had not avalanched on their own. On Lone Mountain the Moonlight Basin ski patrol also triggered avalanches involving fresh wind slabs, and the Big Sky ski patrol noted a recent natural avalanche on Cedar Mountain.
Fresh wind slabs remain the primary avalanche concern. As temperatures rise today wet snow avalanches will also become a concern on S and W facing slopes. Fortunately these avalanche problems can be avoided with simple observations.
Buried facets create the third avalanche problem and require digging a snowpit to assess stability. Dig 4 feet deep and you will either find depth hoar near the ground (photo, video) or a thin layer of small facets. Both layers are adjusting to the weight of new snow that fell Tuesday and last weekend, and stability can vary from one slope to the next. With each passing day the odds of triggering an avalanche on these layers decreases but probably not as quickly as we’d like. Recent avalanches on Cedar Mountain (photos) near Big Sky illustrate the ability of these layers to produce avalanches. Additionally, a recent avalanche (3-5 feet deep) on Lionhead triggered by a falling cornice was spotted yesterday from the smokejumper base in West Yellowstone. For today, wind loaded slopes steeper than 35 degrees have a CONSIDERABLE avalanche danger. A MODERATE avalanche danger exists on less steep wind loaded slopes and all other slopes without a wind load.
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.