Triggered with a cornice drop.

"A first cornice stomp entrained a sizeable sluff, and then a secondary cornice drop trigger a fast, powerful slide that propagated over ridgelines and blasted all the way down to the apron (1,000' vertical feet?). It packed a big punch and would have been bad news to have been caught in. Most of the slab was a result of wind loading in the new snow, which had bonded to the previous 6" and then all slid on the ice layer. The slabs are kind of sticky - they hang in place, but when they cut loose, they are fast. In terrain like this (wind loaded, steep, upper elevation, northish facing) I think the danger is pushing "considerable.""