Evidence of numerous upper and mid slope natural avalanches with wide propagation from storm on NE side Castle/Basin

We toured the NE side of Castle Peak today and counted at least six, mostly filled in crowns with wide propagation from the last storm. These avalanches likely occurred late night/early morning on January 27-28 . Crowns were observed both in upper slope and mid slope start zones on N-NE-E aspects both above treeline and near treeline. Crowns wrapped around rock features and connected as many a three adjacent gully features. Even though these avalanche occurred in areas of wind load, the wide propagation, wrapping around corners, and the connecting together of multiple terrain features gave them the signature of persistent slab avalanches rather than wind slab or storm slab avalanches. The failure layer was most likely the Jan 24 buried surface hoar which was widespread in this area all the way up to the ridgetops.

With is in mind we stuck to lower angle terrain on the NW-N-NE-E aspects that we traveled.

Solar radiation was affecting the SE terrain we traveled with very minimal roller balls off of rocks. A notable stiffening of the snow surface was present on the SE aspects we traveled between 8,200' and 8,700', consistent with sun crust formation. A new surface crust will likely be present tomorrow on many SE-S-SW aspects.

A very thin rime crust was observed on the snow surface in some but not all areas above 8,400'. This crust was most prevalent near ridgetops.

Settlement cracks of up to 2 inches were opening up around trees as is expected post storm and appeared to become more widespread as the day progressed.

Beyond the evidence of recent persistent slab avalanches, no additional signs of instability were noted during our tour from 8 am to 2 pm.