Old and crusty

AST course on the bench below Fraser ridge around 1100m. No signs of instability on the way up but some digging showed that this was likely because of a very strong wind slab supporting us. A very weak faceted crust was 15-25cm below the surface at our study plot and gave a very easy compression test result (CTV sudden collapse) and a moderate Extended Column Test (ECTM sudden collapse). The crust/facet layer showed a strong likelihood of propagation if initiated.

Wind light north in the morning, becoming light-moderate south mid-afternoon as some snow flurries moved into the area from the south

CTV sudden collapse and ECTM sudden collapse. The failure layer is a very faceted, weak crust down 15-25cm at our study site, but overlain by a very strong wind slab 10-20cm thick which was doing a good job of bridging skier weight