Rider came down ridge north of and above Super Couloir. He dropped off the ridge on a S facing slope leading into Super Couloir. Slope avalanched from near the top of the ridge when he was about 100 feet down it. Slab was about 8 inches thick and 300 feet wide. Top of crown was approx 4700 feet elevation. Rider was carried into Super Couloir and part of the way down it, maybe 1000 vertical feet total. He was not buried, but had there been cliffs below him or other terrain traps he would have been in trouble.