We viewed this avalanche from the LCC highway 210 so it's speculation about the details but I'd be surprised if it doesn't fit the pattern of the rest of the recent avalanches.

Weak layer of faceted snow with a crust on top of it then the slab of new snow from Saturday overloaded the facets under the crust.

Photo below: Mark White standing below Mt Baldy holding a piece of crust last week before the storm and the avalanche cycle occurred.