10-11
The weak layer stands out easily in the snowpit. The snow depth almost doubled in the last 72 hours which put a huge stress on the weak layer. Photo: Kyle Rott
This snowpit tells the story. 2 ft of new snow sitting on top of weak - near surface facets that formed during the first few days of February. Our columns were breaking clean on this layer. We did not get any breaks on the lower faceted layer.
GNFAC Avalanche Forecast for Sun Feb 6, 2011
Snowpack and Avalanche Discussion
The Bridger Range, the northern Madison and northern Gallatin Ranges, the mountains around Cooke City and the Washburn Range:
The facets that formed during last weeks cold snap (minus 15F) was capped by a thin melt-freeze crust that formed 3 days later. Fractures are propagating under the ice crust. Photo: Kyle Rott
Forecast link: GNFAC Avalanche Forecast for Mon Feb 7, 2011
This crown on Mount Blackmore indicates instability. This natural avalanche failed on faceted snow formed a week ago. It was about 2 feet deep and 300 feet wide. Photo: Kyle Rott
Forecast link: GNFAC Avalanche Forecast for Mon Feb 7, 2011
A skier remotely triggered this in Pebble Creek, YNP. It propagated wide (around 200'), with a 1-3' crown, running a short distance. The skier assumed the weak layer to be buried surface hoar and small grained facets in combination with a m/f
GNFAC Avalanche Advisory for Sat Feb 5, 2011
Snowpack and Avalanche Discussion
The Bridger, Madison and Gallatin Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
Mud season usually starts around April or May in Montana, but it seems that it has arrived in early February this year. Yesterday, my partners and I skied near Flathead Pass in the northern Bridger Range and got an unexpected dose of wet weather (rain) and yes - mud; not quite what we were expecting. Fortunately, rain levels stayed below 6,000 ft. We did find stable conditions on upper elevation slopes.
GNFAC Avalanche Forecast for Fri Feb 4, 2011
Snowpack and Avalanche Discussion
The Bridger, Madison and Gallatin Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
The primary issue today will be shallow wind slabs formed by strong winds during the last 48 hours. Without much new snow available, these fresh wind slabs shouldn’t be very wide or deep. They will mainly be a problem in terrain where small slides have the potential to sweep a skier or rider over rocks, into trees, or into a confined gully amplifying the consequences of a small slide.
GNFAC Avalanche Advisory for Thu Feb 3, 2011
Snowpack and Avalanche Discussion
The Bridger, Madison and Gallatin Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
The winds have not been confined to the ridgetops. Steady speeds of 20-30 mph are blowing downhill and across slopes at mid and lower elevations. In the last 24 hours wind drifts formed in gullies and on small terrain features which could be triggered today. I don’t expect these wind pillows to be very big since there’s not much loose snow to blow around, but even shallow slabs can fracture and carry us into terrain traps.