Gold Fidge firefighters use a deck gun to protect structures in Coffey Park in Santa Rosa. Picture: Kent Porter/The Press Democrat via AP

Sonoma - Firefighters struggled for a fourth day on Thursday to halt the spread of wildfires that have killed at least 24 people in Northern California and left hundreds missing in the pandemonium of mass evacuations in the heart of the state's wine country.

A resurgence of dry, gusty winds threatened to push flames into the Napa Valley town of Calistoga, whose 5,000-plus residents were ordered from their homes on Wednesday night as conditions worsened and fire crept closer.

Calistoga Mayor Chris Canning warned anyone refusing to heed the mandatory evacuation was "not welcome" in the town and posed a distraction to firefighters.

"You will not be given life safety support," he said during a Thursday morning news conference. "You are on your own."

Fire authorities said crews were beginning to carve containment lines around the perimeters of a handful of fires.

Nearly two dozen blazes spanning eight counties have raged largely unchecked since igniting on Sunday night, scorching 170 000 acres (69 000 hectares) and destroying at least 3 500 buildings.

Entire neighborhoods have been reduced to panoramas of ash, smoldering ruins, charred trees and burned-out cars by a series of firestorms that rank among the deadliest and most destructive in California's history.

Twenty-four people have been confirmed dead, the greatest loss of life from a single California wildfire event since 1991, and authorities said the death toll could climb higher.

"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.

As many as 900 missing-persons reports had been filed in Sonoma County alone, although 437 have since turned up safe, Giordano said.

It remained unclear how many of the 463 still listed as unaccounted for might be 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 14 of the confirmed fatalities, up one from the number reported on Wednesday.


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 National Weather Service warned on Thursday morning of persistent "critical fire weather conditions" in the fire zone for the next three days, with no rain expected and dry winds from the north with gusts upward of 35 miles per hour (55 km/h).

The deadliest of California's blazes, known as the Tubbs fire, 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.

While the cause of the fires have not been determined, they are thought to have been sparked by power lines toppled by gale-force winds and fanned by arid winds that blew into Northern California toward the Pacific on Sunday night.

Wildfires have damaged or demolished at least 13 Napa Valley wineries, a vintners' trade group said on Tuesday.

The confirmed death toll from the spate of fires stood at just one less than the 25 lives lost when a firestorm swept the Oakland Hills in October 1991.

The Tubbs fire, which has accounted for 14 of the deaths, is the worst single blaze since 2003, according to state data.

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.

California Governor Jerry Brown has declared a state of emergency in several northern counties, as well as in Orange County in Southern California, where a fire in Anaheim destroyed 15 structures and damaged 12 earlier in the week.