One of the fires in SoCal - east of the Land of LA - was caused by the pyrotechnics used in a gender-reveal party (I know, that sounds like something from The Onion, but it is true). Another in the LA area was caused by a homeless guy camping by a creek whose campfire got out of control.
Warmistas do talk about those sorts of human causation.
FWIW, I live in Silicon Valley, and out skies have been overcast the past 3 days, the full days, due to smoke from fires to the north of us in NorCal and Oregon. So I'm well aware of the weather phenomenon to which Star Moron lambchopp59 referred. It is unusual in degree, somewhat, but not unique.