Good morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Monday, March 5 at 7:30 a.m. The Pinhead Classic Telemark Festival, in partnership with the Friends of the Avalanche Center, sponsors today’s advisory. This advisory does not apply to operating ski areas.
If you liked yesterday’s weather, you’ll love today’s. Mountain temperatures reached the mid-30s at the ridgetops, but hit 40F at mid elevations under sunny skies. Today will be 5-10 degrees warmer. Winds will continue blowing out of the west at 25-40 mph. Tonight will become cloudy and tomorrow a fast moving front will cool things off and bring snow to the mountains. Behind this system is more sun, warmth and spring-like weather lasting through next weekend.
The Bridger, Madison and Gallatin Ranges, the mountains around Cooke City and the Lionhead area near West Yellowstone:
There were many avalanches and signs of instability over the weekend. Yesterday the Yellowstone Club Ski Patrol saw slides on Cedar Mountain, one triggered by a snowmobiler who launched onto a wind-loaded slope midday. They sent in three crisp pictures of the avalanche activity. A skier in the southern Madison Range this weekend saw upwards of 20 crowns in the backcountry, many recent and some reaching six feet deep. On Saturday he was able to trigger a slope with a cornice drop that broke 18” deep on the new/old snow interface. On many slopes avalanches broke on a layer of small facets buried two to three feet under the surface. He also saw two natural avalanches release on a south-facing slope that ran over 1,000 feet vertical.
I was in the Bridger Range yesterday. I dug a pit on the west side near the top of Truman Gulch and was not psyched about what I found. It was basically garbage. Large depth hoar is poorly supporting three or more feet of snow. It was breaking easy in my stability tests (video, photo). I also saw four older crowns. My concern is that a person could trigger an avalanche on these large facets which would propagate into deeper, wind-loaded terrain. These wind-loads are not just at the ridgetops; over the weekend mid-mountain winds created drifts on the edges of many gullies. My partner and I then hiked to the top of Saddle Peak with the intention of digging a pit near the south summit. Winds scoured the ridgeline (photo) and filled in the crown from the human triggered slide on February 24. I was nervous about getting on the slope since it reloaded, so I retreated.
It’s not all gloom and doom out there. The probability of triggering avalanches is steadily decreasing, but given the poor snow structure the odds won’t hit zero anytime soon. Facets at the ground and a thin layer two to three feet under the surface are here for a while longer. Slopes with wind-loading from this weekend are still susceptible to avalanching. For today, the avalanche danger is rated CONSIDERABLE on wind-loaded slopes as well as any slope steeper than 35 degrees. All other terrain has a MODERATE danger.
WET SNOW AVALANCHES
Above freezing temperatures yesterday melted the snow surface on many sun exposed slopes. Wet avalanches were seen in the gullies up Hyalite and also at the ski areas. Today will be even warmer and direct solar radiation will again melt the upper few inches of the snowpack. Wet loose snow slides will increase throughout the day and possibly act as triggers for deeper avalanches.
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.
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.