I saw this soft slab from across the canyon.  I wasn't able to get a closer look but from what I could tell it was likely a natural release that occurred the previous day.  Flat light made it difficult to tell exact numbers but it looked to be about 12-18 inches deep, 100 ft wide and had run around 300-400 vertical feet.  The wind had filled in over top the debris pile and there were no sled or skier tracks nearby.  Sorry for the crummy cell phone photo.