The deaths on Wednesday of a utility worker and helicopter pilot participating in the fire response came after nearly 11,000 lightning strikes hit the state over a 72-hour stretch this week, igniting 367 fires. Authorities are warning all 40 million state residents to be ready to evacuate, if necessary.
At least nine fires raced through hills and mountains adjacent to Northern California's drought-parched wine country about 35 miles (56 km) southwest of Sacramento.
With several joining up, they formed a 131,000 acre (53,000-hectare) "megafire" nearly 10 times larger than New York's Manhattan island across five counties.
Collectively known as the LNU Complex Fire, the fires destroyed at least 105 structures in the Vacaville-Fairfield area. A PG&E utility worker died helping first responders and at least four civilians were injured, according to a California Department of Forestry and Fire Protection (CalFire) spokeswoman.