Sonoma - Fuelled by the return of strong winds, the wildfires tearing through California wine country exploded in size and number on Wednesday as authorities ordered new evacuations and the death toll climbed to 21 - a figure expected to rise higher still.
Three days after the fires began, firefighters were still unable to gain control of the blazes that had turned entire Northern California neighbourhoods to ash and destroyed at least 3 500 homes and businesses.
"We are literally looking at explosive vegetation," said Ken Pimlott, chief of the California Department of Forestry and Fire Protection. "It is very dynamic. These fires are changing by the minute in many areas."
The entire historic town of Calistoga, population 5 000, was evacuated. In neighbouring Sonoma County, authorities issued an evacuation advisory for part of the town of Sonoma and the community of Boyes Hot Springs. By that time, lines of cars were already fleeing.
The wildfires ranked as the third deadliest and most destructive in state history. And officials warned the worst was far from over.
"Make no mistake, this is a serious, critical, catastrophic event," Pimlott said.
The fires have burned through a staggering 686km² of urban and rural areas. High winds and low humidity made conditions ideal for fire to ignite virtually anywhere on ground or brush that was parched from years of drought.
Cal Fire spokesperson Daniel Berlant said 22 wildfires were burning on Wednesday, up from 17 the day before. As the fires grow, officials voiced concern that separate fires would merge into even larger infernos.
"We have had big fires in the past. This is one of the biggest, most serious, and it's not over," Governor Jerry Brown said at a news conference, alongside the state's top emergency officials.
They said 8 000 firefighters and other personnel were battling the blazes and more resources were pouring in from Oregon, Nevada, Washington and Arizona.
Flames have raced across the wine-growing region and the scenic coastal area of Mendocino farther north, leaving little more than smoldering ashes and eye-stinging smoke in their wake. Whole neighborhoods were leveled, leaving only brick chimneys and charred appliances to mark sites that were once family homes.
In Boyes Hot Springs, residents for days had watched the ridges over the west side of town to gauge how close the billowing smoke and orange flames of the wildfires had come. On Wednesday, the ridges themselves were obscured by the growing clouds of smoke.
Charred wine barrells sit on racks at Paradise Ridge Winery. (Justin Sullivan, AFP)
Increasingly large pieces of gray ash drifted down on the community. Sirens wailed. Residents who had held out hope of staying at home, packed up to leave.
With fires advancing from several sides in Sonoma Valley, law enforcement officers on loan from other areas of Northern California barred residents of evacuated communities from returning to see how the homes and businesses had fared. Manned roadblocks blocked routes between Sonoma and devastated areas of Santa Rosa.
Alejandro Rodriguez had been evacuated from one tiny Sonoma Valley town, only to have deputies come to the neighbourhood he had relocated to and tell residents there to pack up to go.
"I want to see my house, see if any things left," Rodriguez said, gesturing at officers at one roadblock. "They won't tell us nothing."
Sonoma County Sheriff Robert Giordano said hundreds of people were still reported missing. But officials believe many of those people will be found. Chaotic evacuations and poor communications over the past few days have made locating friends and family difficult.
"The devastation is enormous," he said. "We can't even get into most areas."
Authorities say most of Sonoma County's 11 victims lived where steep, narrow roads wind through the hillsides with few ways out.
Helicopters, air tankers and nearly 8 000 firefighters were trying to beat back the flames. Until now, the efforts have focused on "life safety" rather than extinguishing the blazes, partly because the flames were shifting with winds and targeting new communities without warning.
Fires were "burning faster than firefighters can run, in some situations", Emergency Operations Director Mark Ghilarducci said.
In Southern California, cooler weather and moist ocean air helped firefighters gain ground against a wildfire that has scorched nearly 36km².
Orange County fire officials said the blaze was 60% contained and full containment was expected by Sunday, although another round of gusty winds and low humidity levels could arrive late on Thursday.