This was one of three snowmobiler triggered avalanches that I stumbled across in Seeley Canyon. I'm guessing that they were all triggered by the same group as there were not many tracks in the drainage. I was a bit surprised to see that they broke into older faceted snow. However, upon inspection, it makes sense at these locations. The upper bowls along the Skyline receive a good amount of wind damage. This sometimes erodes snow leaving a very shallow snowpack that is easily subject to faceting. No doubt, that was the case. All of these avalanches were in areas where there was only about a foot of old snow which was quite faceted. Many areas had over 3 feet of snow prior to this storm and have a much better structure.