At least one person has been killed and two seriously injured in fast-spreading wildfires in northern California wine country, officials say.
CalFire said the death and injuries occurred in Mendocino County, one of several counties struggling to contain 14 major fires burning out of control.
The fires, whipped by powerful winds, have destroyed at least 1,500 homes and businesses and sent about 20,000 people fleeing to safety.
The state's fire chief called the damage estimates for the fires conservative and said they were burning throughout an eight-county stretch of northern California, including Napa, Sonoma and Yuba.
Numerous people have been hurt and some are missing, although no estimates were immediately available, said California Department of Forestry and Fire Protection director Ken Pimlott.
Mandatory evacuations were ordered after the blazes broke out late on Sunday. Long queues formed at filling stations when families heeded a middle-of-the-night call to get out.
A spokesman for Pacific Gas & Electric said 114,000 customers were without power.
Fires also burned just to the east in Napa County as well as in Yuba, Butte and Nevada counties - all north of the state capital. Many of the fires spread suddenly overnight, whipped by furious winds.
Santa Rosa, the largest city in the fire area with a population of about 175,000, was hit hard. The city lost unknown numbers of businesses and homes as the blaze shut down schools and forced patients at two city hospitals to evacuate.
A Hilton Hotel was smouldering and in ruins.
More than 200 people were hurriedly evacuated from Sutter Santa Rosa Regional Hospital and Santa Rosa Medical Centre, where the blaze could be seen raging nearby.
Napa County Fire Chief Barry Biermann said the fires had burned more than 68 square miles. Crews had not yet been able to contain a fire heading toward central Napa.
"Right now, with these conditions, we can't get ahead of this fire and do anything about the forward progress," Mr Biermann said.
Governor Jerry Brown declared a state of emergency in Napa, Sonoma and Yuba counties.
Smoke was thick in San Francisco, 60 miles south of the Sonoma County fire.
Emergency lines were inundated with callers reporting smoke, prompting officials to ask that the public "only use 911 if they see actual unattended flames, or are having another emergency".
The National Weather Service said widespread wind gusts between 35mph and 50mph were observed in the north San Francisco Bay region and isolated spots hit 70mph. The winds were expected to subside later.