We were at Cooke the weekend of those slides. The guys that were on sleds did almost everything wrong that you could have done to cause the slide, which is unfortunate because it was a father with his sons. When we pulled into Cooke that morning everyone warned us of the extreme avalanche danger. Everywhere we rode we saw natural slides and sled triggered slides. One rider in our group triggered a slide that wasn't huge but big enough that it could have cause some serious trouble for him, but he rode out of it.
The skier who died was in a runout area and probably shouldn't have been where he was. It sounds like the slide that killed him was a natural slide.
This was all triggered by 2 ft. of snow on an unstable layer.
I just attended a Mike Duffy Avalanche class on Monday night. This is a class that I recommend to all mountain riders.