General Observations

Observed a natural avalanche that was most likely triggered during the strong wind event Dec. 12 and failed on a persistent weak layer 1-4ft deep. This hard slab avalanche was 200ft wide and ran 800ft with the destructive size to to bury, injure, or kill. The average slope angle of the path measured on Google Earth was 35 degrees. A large rock protruding near the deepest crown line ~3-4ft deep was probably where the slide initiated because the weak layer was closest to the surface, then propagated downhill towards another thinner rocky outcrop.

• This is a useful piece of information for the forecast because we are seeing avalanches on persistent weak layers and know they are around.
• Understanding the underlying terrain helps identify shallow areas in the snowpack where you are most likely to trigger a slide from.
• There was older slide debris lookers right and this slide path was re-filling over the weak layer that failed and could fail again.