Firefighters are beginning to gain ground against wildfires that have killed at least 29 people in Northern California and left hundreds missing in the chaos of mass evacuations in the heart of the state's wine country.
The latest casualty figures mark the greatest loss life from a single California wildfire event in 84 years with 3,500 homes and businesses incinerated and 77,000 hectares scorched.
Whole neighbourhoods in the city of Santa Rosa have been reduced to gray ash and smouldering ruins dotted with charred trees and burned-out cars.
The official cause of the disaster is under investigation, but officials say power lines toppled by gale-force winds on Sunday night may have sparked the conflagration.
A resurgence of extreme wind conditions that was 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 are expected to return across much of the state as early as Friday night, and a force of 8,000 firefighters in Northern California are 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 Pimlot, director of the California Department of Forestry and Fire Protection (Cal Fire), told reporters in Sacramento.
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.
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.