Did not see the person making the slide. Viewed it within an hour or less of it happening by the lack of new snow on the bed surface. Person appeared to be riding down the Dog Lake Chutes and made a cross slope turn and initiated a wide/substantial Dry Loose Avalanche that dug down to the old snow new snow interface upon descent, and was at least 90 feet wide. Tracks rode out of the debris. The debris piled up to be at least 2 feet if not 3 and ran to the transition. Of note the entire rider's right half of the Main Dog Lake Chute had multiple Natural Dry Loose Avalanches that appeared to be initiating from the steep North facing cliff bands and these also ran to the transitions. Hand Shears and Tilt Tests confirmed the obvious weakness that only got deeper as the day progressed. Snow fall rates were sustained in the S3 to S4 range for the most of the entire day with HN from 0900 exceeding 6 inches, and the HST 14 inches. Snow was extremely light density and there was good bonding to the old snow/new snow interface as the storm came in Rightside up. Still experiencing isolated collapsing, but as visibility was poor most of the day it was difficult to see any other Avalanche Activity.