From an email:
"Dug a pit at ~9000’ on a NE aspect, got a ECTP29 at 56cm down, breaking below the new snow and a 12cm knife-hard slab. Broke on small facets (<1mm) in between wind slabs. I marked the trigger point in red. Skinned up a low angle gully up to around 9500’. As I got near the steepest part of the gully (38°), a soft slab 12-18” thick propagated 100’ wide and slid 500’ back down to my pit. No one was caught. Contrary to my pit, this ENE aspect slid just the new snow on top of a previous wind slab. No facets on the bed surface, just new snow/old snow interface. Found safer skiing down low in the trees where there was less wind loading."