Rider fell off the ridgeline during white-out conditions (possibly a cornice break). He dislocated a shoulder in the fall, came to a stop and removed his pack to assess the injury. His partner dropped in to assist but triggered an avalanche which ran down and caught the injured rider. The rider was tumbled, sometimes submerging in the debris but came to the surface just as the debris stopped moving.

I was up there on Sunday and took some photos of the area where the avalanche was indicated to have released. I'm guessing it must've been the longest running slide just right of the high point in these photos. Kobernik