Wildfires fanned by strong winds have ripped through Californian wine country, killing at least 10 people, forcing some 20,000 residents to flee and destroying 1,500 homes and businesses.
Governor Jerry Brown declared a state of emergency for Northern California's wine-making Napa, Sonoma, and Yuba counties as the blazes raged unchecked and engulfed the region in thick, billowing smoke that drifted into San Francisco and Oakland.
A state of emergency was also declared in Butte, Lake, Mendocino, Nevada and Orange counties.
Californian authorities said at least seven people had died in the winemaking region of Sonoma, two in neighbouring Napa, and one-person died in a blaze further north.
Thousands of firefighters battled wind gusts in excess of 80 kilometres per hour as 14 wildfires — several out of control — in eight northern California counties burned through more than 23,000 hectares since the weekend, CalFire spokesman Daniel Berlant said.
About 1,500 homes and commercial buildings have been destroyed, Ken Pimlott, director of CalFire, told a news conference.
The blazes included the so-called Tubbs fire in Napa County, about 113 kilometres north of San Francisco in an area world-famous for its vineyards.
It had scorched about 10,117 hectares of land as of this morning, according to CalFire.
John Van Dyke, standing in his pyjamas near the 101 Freeway in Santa Rosa, watched a hillside in flames from the Tubbs Fire — police pounded on his door in the mobile home park, telling him to evacuate.
"When I got in the car to leave, a whole section of the mobile park was in flames," he said. "It scared the hell out of me.
Authorities imposed a sunset-to-sunrise curfew in Santa Rosa, saying they were on the lookout for looters.
San Francisco authorities issued an air quality alert due to smoke from the fires, which residents said they could smell from the early morning hours.
Wesley Carr, 23, a resident of Sebastopol in Sonoma County, said that smoke from the fires had enveloped the area.
"The sun is a pale yellow, that's how thick the smoke is," he said, adding that ash was floating in the air from one of the fires, which he estimated is about 50 kilometres away.
On Tuesday, another wildfire also torched a handful of homes in Southern California in the affluent Anaheim Hills neighbourhood in Orange County.
The blaze erupted along the 91 Freeway next to an off-ramp and spread quickly in gusty winds to char more than 202 hectares, Orange County Fire Authority spokesman Captain Larry Kurtz said.
Authorities in the cities of Anaheim, which includes Anaheim Hills, and Orange ordered hundreds of residents to evacuate.
Firefighters rushed to a state home for the severely disabled when flames reached one side of the centre's sprawling campus in the historic Sonoma County town of Glen Ellen.
Crews got more than 200 people from the threatened buildings, one firefighter said, as flames closed within a few dozen metres.