Cornice fails onto PWL

I'm sure many folks on this forum already knows this, but since I have no social media I was surprised to see the epic crown in Chair Peak basin yesterday 3.13.21.
Up to 20' high, this crown seems to show the snowpack has failed on this years reported weak layer. Discussion indicates a cornice triggered this avalance.~a week ago.

There are many huge conrnices out there this year due to the high snow. 
I'm unsure what exactly causes cornice failure in addition to rising temperatures. Perhaps afternoons are more likely?