I triggered it with a snowbike. I was trying to ride up through the trees on the north west side but followed others toward the north face (north east). I saw someone stuck in a tree on that north east face so I turned around to help. When I wrapped around a tree my bike washed out from underneath me and tipped over up hill. I stood back up to see the slide happen from the bottom of my snowbike. Fortunately the tree above me kept any snow from sliding above me. The snow depth was probably 16 inches. The width about 150 feet and the length about 200 feet.

Again, nobody was caught in the slide.

A snowmobiler in our group actually triggered another avalanche a little later in the day and he didn't even know it.