Avalanche: Mill B South

Was ascending the slope when I heard a thump sound, I immediately looked down and noticed cracking 10ft downslope. I knew it was game on at that point. I quickly tried to ski to the side (on a splitboard) but sure enough I was caught and moving with the snow. I managed to deploy my airbag and lucky enough was able to stay fully on top. All morning I had only experienced fluffy snow without any obvious slab formations. Perhaps I had let my guard down and was more worried about sluffing. But as soon as I realized there was a slab underneath, it was too late, the slide had begun. The avalanche went about 100 vertical feet and 20 to 30 feet wide at its crown, carrying me 75% of the way. No injuries sustained.