New snow avalanches and weak facets

New snow avalanches and weak facets

Date
Activity
Skiing

We skied into Frazier Basin, and down into Ainger Lake area. We dug our first snow pit on a north-facing slope below Thing One and Thing Two. The Snowpack was deep, and the upper meter consisted of layers of wind slabs on top of wind slabs (Ectx). We dug again on a northeast-facing slope below Frazier basin. Similarly, we found a deep snowpack with no notable weak layers in the upper 4 feet. We dug a third pit on a southeast-facing slope as we skinned out. The snowpack was much thinner (140cm), and we found weak depth hoar buried 3 1/2 to 4 feet deep with an unstable test result (ectp21). The instability was related to the snow depth rather than the aspect. Given that there was a large natural avalanche a few basins to the south a week ago, we remain concerned about avalanches breaking deep in the snowpack.

As we returned to Frazier Basin from below, we immediately saw five natural avalanches on the southeast-facing wall of the basin. These had occurred while we were skiing the terrain below. They entrained only the 1 to 2 inches of snow that had fallen during the day. However, they were notable in that they ran 500 to 700 vertical feet. They were likely initiated by warming from the proximal cliff faces. They indicate that the new snow may not bond well to the old snow surface. A crust formed by the recent warm temperatures and sunny skies is the subsurface that snow is falling on. This will become a more significant concern as more snow falls this week.
 

 

Region
Bridger Range
Location (from list)
Frazier Basin
Observer Name
David Zinn