Professional Observation

Observation Details

Signs of Unstable Snow

Snow Stability

Key Points

We took a lovely holiday walk up Patricia Peak in Rock Creek to look at as many aspects and elevations as possible before an atmospheric river hits the East Side starting Monday night.

• The snowpack warmed more than we expected below 9500 feet, especially on solar aspects, in the trees and areas with a thin snow cover near rocks. We triggered some large rollerballs and sank to our knees in wet snow – with our skis on. We didn’t see any wet loose avalanches or natural rollers. We traveled on some steep slopes with wet snow in the afternoon and pinwheels were the only thing we triggered.
• New snow will fall on a variety of snow surfaces. The constant is poor snowpack structure near the ground on shaded aspects near and above treeline. On the upside, this is the first time I have seen improvement in the persistent weak layer in Rock Creek this season. We got no collapses or shooting cracks – a first! The facets are getting denser, and we got mixed test results – rather than repeated propagation – in our long column tests. The caveat is that a lot of water is on the way, and I still expect avalanches to fail on this layer after heavy and rapid loading.