Looking at the pictures that's the way to East Quartz. That narrow creek at the end of the cut-block is the common way in. You need a good snow year or slides to fill the creek in enough to make it passable. I can't imagine anyone was climbing up the chute that slid, especially up to where the slide started. Too narrow and too many trees part way up. Perhaps they were messing around at the bottom and the noise triggered it?