Avalanche on Andesite

The topic of the day was whether or not the new storm snow was bonding to the December 15th rain crust. We dug several hand pits during our walk up Andesite this morning and didn't note anything super reactive. Well, with the exception of one widesperad woomph on the West aspect of Andesite towards the top. Full pit observations from the East aspect at the top of Andesite revealed a few density changes within the new snow but nothing that propagated an ECT and the interface between then rain crust and the new snow seemed stable enough. 

There was discussion however, between us and one of our local SAC forecasters regarding buried near-surface facets on top of the Dec 15th rain crust. It was noted that in areas effected by wind they seemed absent but had been observed closer to, and below treeline. 

In any event, on our second run I skied a low-ish angle slope to the skiers right of Andesite's summit proper, if it was over 30 degrees it couldn't have been by much. At the bottom of the slope I encountered a steeper convexity. This steeper piece of terrain was relatively small and I decided to make a turn on the roll over, mostly out of curiousity. I did so, witnessed a crack, skied left with some speed into the trees where I looked back and observed this small but pretty significant slab pull out and run a short distance to the trees below. No one was caught and the rest of my group skied lower angle terrain to the south. 

Although I didn't skin back up to take a closer look, the piece that came out appeared to have run on the rain crust. It seemed about 18-24" deep and maybe 20-25ft wide. I think you would have been hard pressed to be fully buried by the debris but it was certainly enough snow to cause injury.