GNFAC Avalanche Advisory for Tue Mar 3, 2009
The Bridger, Gallatin and Madison Ranges, including the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
GNFAC Avalanche Advisory for Mon Mar 2, 2009
The Bridger, Gallatin and Madison Ranges, including the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
GNFAC Avalanche Advisory for Sun Mar 1, 2009
The Bridger, Gallatin and Madison Ranges, including the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
GNFAC Avalanche Advisory for Sat Feb 28, 2009
The Bridger, Gallatin and Madison Ranges, including the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
GNFAC Avalanche Advisory for Fri Feb 27, 2009
The southern Gallatin and southern Madison Ranges, including the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
This 40 degree northwest facing slope consisted of large, weak facets. This 3 foot deep snowpack will become quickly unstable if/when we get more snow. This is one of the weakest snowpacks in southwest Montana.
These 2 layers of surface hoar are buried 1.5 feet from the surface at Lionhead in the southern Madison Range. They\'re providing clean shears in our stability tests and are something to look out for in your travels.
Near Cooke City, as soon as we would ski across a slope that was wind affected we would get shooting cracks on the recently buried facets. Most areas do not have this instability--yet. But when it snows we'll likely see more avalanches on it.
These slab avalanches on south facing slopes near Cooke City fractured about a foot down. While not large these avalanches show the weakness of a layer of facets near an ice crust. Photos: B. Fredlund