All the fracture lines blown in. Most everything in the upper cirque from the Pfeifferhorn to Redbird Pk had a fracture line. Likely occurred overnight. Only one collapse on a wind loaded wind-roll. Otherwise skiing through thin rain crust with bottomless squares below. 1-2mm rain crust up high, 3cm friable crust down low. Facets noted beneath mid-elevation crusts...

Photo below of collapse/crack and the upper headwall.