I hate to keep talking on this one, but there is a lot that can be learned here.
CAIC has their preliminary report out.
CAIC: Colorado Avalanche Information Center
He was riding in the exact area that I thought he was. From the report from his friend, sounds like the slide released from above the cliffs. Not a good scenario. Those cliffs have a convex roll and get very wind loaded. A trained eye would instantly see this.
Avalanches just don't care if you are an expert, novice, uneducated, superhero, dog, whatever. They will take anyone and anything out that annoys them.