Reactive persistent slabs and sluffs

CB Avalanche Center2016-17 Observations

Location: Brush Creek Area
Date of Observation: 02/28/2017
Name: Zach Guy
Subject: Reactive persistent slabs and sluffs
Aspect: East, South East
Elevation: 10600-11600

Avalanches: Skier triggered numerous loose snow avalanches in the top 12″ of the storm snow, up to D1.5 in size. Remotely triggered a small rollover from below, failed about 20″ deep on the 2/17 facet layer. SS-ASr-R1-D1-O. Poor vis, no other avalanche observations.
Weather: S-1, Overcast to broken skies, winds increased through the day, becoming strong and transporting lots of snow.
Snowpack: 18″ of storm snow at Friends Hut. The top 12″ came in very low density (~3%). Widespread loose snow instabilities, but the storm snow became slabbier through the day due to settlement and wind affect. Persistent weak layers (near surface facets and thin crust/facets) were reactive: multiple moderate collapses, a 100′ shooting crack, and remote triggered a small pocket, all on buried facets about 18-24″ deep. The most concerning structures were on ESE and E aspects, where there are thin crusts surrounded by facets.