Pierre and a friend were skiing the resort which has had heavy snowfall in recent days but was not yet open to the public and had not carried out any avalanche control work.
Pierre was a star of many ski movies and had made a number of first jumps on previously unskied terrain, the longest up to 80m.
The Utah Avalanche Center's report states:
"We interviewed the victim's ski partner. While neither had any rescue gear or formal avalanche training, they were both expert skiers and new the terrain well.
"With the partner watching, the victim dropped into the slope, immediately triggereing the slide. He was carried hundreds of feet through steep rocky terrain and reportedly went over a small cliff band and came to a stop only partially buried."
"Collapsing of the snow pack occurred all week prior to the accident. There were two slab avalanches triggered early in the week and no less then 12 human triggered avalanches during the day of the accident. Over an inch of water weight was added to our weak pre existing snow, obviously too much weight for the snowpack to stay put with people on the steeper slopes."