Ohhhh, that's just creepy! Thank God he and his friends were well prepared. What's amazing is how motionless the camera was once the 'concrete' set. I have to wonder how much time/room he had to get his air source started before being locked in solid. It also sounded like his friends were "pinging" him with their cell phones. Beacon maybe?
I've skied post-avalanche crud before and there is no doubt you don't simply "swim" out of that stuff.