The latest casualty figures, revised upward by six fatalities on Thursday, marked the greatest loss life from a single California wildfire event in 84 years. With 3,500 homes and businesses incinerated, the so-called North Bay fires also rank among the most destructive in state history.
The fires have scorched more than 190,000 acres (77,000 hectares), an area nearly the size of New York City, reducing whole neighbourhoods in the city of Santa Rosa to grey ash and smouldering ruins dotted with charred trees and burned-out cars.
The official cause of the disaster was under investigation, but officials said power lines toppled by gale-force winds on Sunday night may have sparked the conflagration.
A resurgence of extreme wind conditions that had been forecast for Wednesday night and early Thursday failed to materialise, giving fire crews a chance to start carving containment lines around the perimeter of some of the blazes.
But fierce winds were expected to return across much of the state as early as Friday night, and a force of 8,000 firefighters in Northern California were racing to reinforce and extend buffer lines before then, officials said.
Despite progress, fire crews remained "a long way from being out of the woods," Ken Pimlott, director of the California Department of Forestry and Fire Protection (Cal Fire), told reporters in Sacramento, the state capital.
Mark Ghilarducci, state director of emergency services, added that: "We are not even close to being out of this emergency."
Authorities have warned that the death toll from the spate of more than 20 fires raging across eight counties for a fourth day could climb higher, with more than 400 people in Sonoma County alone still listed as missing.
'You are on your own'
One of greatest immediate threats to population centres continued to be in the Napa Valley town of Calistoga, whose 5,000-plus residents were ordered from their homes on Wednesday night as winds picked up and fire crept closer.
Calistoga Mayor Chris Canning said anyone refusing to heed the mandatory evacuation would be left to fend for themselves if fire approached, warning on Thursday: "You are on your own."
Twenty-nine people, all civilians, were confirmed dead in four counties, tying the record for California's most lethal wildfire, the 1933 Griffith Park fire in Los Angeles.
Fire officials have said some victims from the latest fires were asleep when flames engulfed their homes. Others had only minutes to escape as winds of over 60 mph fanned fast moving blazes. Ghilarducci said the loss of cellular communications towers likely contributed to difficulties in warning residents by mobile phone alerts.
"We have found bodies that were completely intact, and we have found bodies that were no more than ash and bone," Sonoma County Sheriff Rob Giordano told reporters. He added that recovery teams would begin searching ruins with cadaver dogs.
It remained unclear how many of the 463 still listed as unaccounted for are actual fire victims rather than evacuees who failed to alert authorities after fleeing their homes, he said.
"The best we can pray for is that they haven't checked in," emergency operations spokeswoman Jennifer Larocque told Reuters.
Sonoma County accounted for 15 of the North Bay fatalities, all from the so-called Tubbs fire, which now ranks as the deadliest single California wildfire since 2003, according to state data.
Smoke, ash in Bay Arena
About 25,000 people remained displaced on Wednesday as the fires belched smoke that drifted over the San Francisco Bay area, about 50 miles to the south, where visibility was shrouded in haze and automobiles were coated with ash.
The fires struck the heart of the state's world-renowned wine-producing region, wreaking havoc on its tourist industry while damaging or demolishing at least 13 Napa Valley wineries.
The Tubbs fire on Thursday was within 2 miles (3 km) of Calistoga, which had appeared to be in the path of advancing flames but was spared on the first night of the fires.
Whether the town burns "is going to depend on the wind," Calistoga's Fire Chief Steve Campbell told Reuters early on Thursday. "High winds are predicted but we have not received them yet."
New evacuations also were issued in Sonoma County late on Wednesday for parts of Santa Rosa, the largest city in the wine-producing region, and Geyserville, an unincorporated town of 800 people.
In addition to high winds, the fires have been stoked by an abundance of thick brush left ready to burn by a dry, hot summer.
(Additional reporting by Stephen Lam, Dan Whitcomb, Steve Gorman and Alex Dobuzinskis in Los Angeles, Sharon Bernstein in Sacramento, Jonathan Allen in New York, Brendan O'Brien in Milwaukee and Jeffrey Dastin in San Francisco; Writing and additional reporting by Steve Gorman in Los Angeles; Editing by Bill Trott and Andrew Hay)
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