At approximately 10am, as I got to a a safe location on the ridge, before I was even ready to stomp a cornice, the entire slope released below me, and where it was triggered, the crown was approximately 2.5'-3' deep.  The slide ran all the way down to the bottom of the basin, full track, I would say it was R2D2.  Attached are some pictures of the slide.  I did not feel comfortable after poking around trying to get on the sketchy bed surface, with the hangfire, doing a crown profile, although it was clear it was the ground interface, and facets just above which was the bed surface and weak layer.  In one place you can see it stepped down from approximately 8-10" to about 2'.

Alta Ski Area was not open yet for the season.