Body recovery teams with cadaver dogs were searching Thursday for victims of California's wildfires as reinforcements arrived to help exhausted firefighters battle some of the worst infernos the state has ever seen.
The death toll rose to 27 meanwhile from the wildfires, which began on Sunday and have left thousands of people homeless. Authorities said they expect it to rise further.
Gusty winds on Thursday were hampering the efforts of the 8,000 firefighters battling 21 blazes which have burned 191,437 acres (77,500 hectares), and weather conditions were not forecast to improve.
"What this means is that our fires will continue to burn erratically" California fire chief Ken Pimlott told a news conference. "They have the potential to shift in any direction at any time.
"We are a long way from being done with this catastrophe," he said.
Sheriff Rob Giordano of hard-hit Sonoma County said his department has received 1,000 reports of missing persons, but about 600 of them have been found safe so far.
"Those are big numbers," he said, but "sometimes we get duplicates of people.
"So in those 1,000 reports someone could be reported more than once," he said. "And a lot of it is communications issues -- cellphone towers are down, people don't have their chargers with them."
He said targeted body recovery efforts had begun in cases where all other leads were exhausted.
"We're moving into a recovery phase," he said. "We have cadaver dogs up here that can basically scent bodies and help us find people."
Giordano warned that it was "going to be a slow process" as fires continue to burn, and that identifying victims would be difficult.
"We have found bodies that were completely intact and we have found bodies that were nothing more than ash and bones," he said.
Fifteen deaths have been reported in Sonoma County, eight in Mendocino County, two in Yuba County and two in Napa County.
Asked if he expected the death toll to rise, Giordano replied: "I'd be unrealistic if I didn't."
As recovery teams fanned out searching for fire victims, evacuation orders were issued for towns in wine-producing Napa and Sonoma counties, where hundreds of people have already lost their homes to the fast-moving infernos.
Residents of Calistoga, a resort town of some 5,000 people in Napa, and Geyserville, a town of around 800 people in Sonoma, were told to leave and seek shelter elsewhere.
Entire neighborhoods in Santa Rosa have been reduced to ashes, and evacuation orders were issued for additional parts of the devastated city of 175,000 people in Sonoma County.
The California Department of Forestry and Fire Protection (Cal Fire) said meanwhile that strong winds could spark new fires.
"These winds will continue to challenge firefighters in their efforts towards containment and will increase the risk for new fires," Cal Fire said.
The National Weather Service said wind gusts of up to 50 miles (80 kilometers) per hour were forecast in some areas and the "critical fire weather conditions" would continue into the weekend.
Pimlott, the Cal Fire chief, said hundreds of fire engines and dozens of firefighting crews were being brought in from other states.
"Hour by hour more resources pour in," he said.
A state emergency management official said the authorities were looking into bringing in firefighters from as far away as Australia.
David Shew, a veteran firefighter with Cal Fire, said the wildfires were like nothing he's seen before.
"I've been with Cal Fire for 30 years and I've seen big fires," he told AFP. "But this is extraordinary, having that many and that large and going so fast."
Thousands of people have been left homeless and 25,000 people have evacuated their homes in Sonoma County alone, according to officials.
More than 3,500 homes and businesses have been destroyed, including several wineries in Sonoma and Napa counties, the heart of the state's extensive wine production.
President Donald Trump has declared a major disaster in California, freeing up federal funding and resources to help fight the fires, and Governor Jerry Brown has declared a state of emergency in eight counties.
Michael Desmond, 63, was among the hundreds of residents of Santa Rosa's Coffey Park neighborhood who lost their homes.
"I feel violated, like a thief came in," said Desmond, who sobbed as he surveyed the rubble of the house where he grew up.
Forest fires are common in the western United States during the summer but this year's blazes in California are among the deadliest ever.
The Griffith Park fire in Los Angeles County in 1933 killed at least 29 people, and 25 people died in the 1991 Oakland Hills fire.