Headed into the Hallway Couloir on Red & Benson ridge knowing we'd need to get the new snow to run or we wouldn't be comfortable skiing it. We also knew if it was reacting like anything like what we'd seen in Main Days it wouldn't take much. The first north facing pitch was stable. After first skier skied to island of safety on East side of couloir (right where it dog legs left) it went. It didn't even take a ski cut as he hadn't had a chance to do it. Just skiing down near made it slide. Depth varied by wind loading location from 3 inches to 1 foot deep. It ran all the way down to the tube (estimated 800 feet down).