3-5" of fresh snow is the official word from Mt. Baldy, in the San Gabriel Mountains, but peering through the haze today from Kenneth Hahn State Park, I'd say coverage on Baldy's west face might be a little deeper. Maybe. Then again, I am trying to go with optimism as our winter season draws near. Third time's a charm, right?
Mammoth reports around a foot and a half of new snow, but there was nothing underneath it, so you'll still have to decide whether or not it's worth it to drive up for what amounts to 4 open runs. As for SoCal backcountry, I have received iron-clad evidence that it's not yet happening: SMS legend Alvin hiked up the Ski Hut Trail and found "not enough snow to justify taking skis."
If Alvin won't ski it, you'd don't want to ski it, either. Patience...
Andy Lewicky is the author and creator of SierraDescents