Firefighters struggled overnight to halt the spread of wildfires known to have killed 23 people in North California, preparing for winds to shift after one town threatened by flames evacuated all residents.
The edge of the deadly Tubbs fire was less than two miles from Calistoga, a Napa Valley community whose 5,000 residents left their homes on Wednesday.
Whether the town burns "is going to depend on the wind," its Fire Chief Steve Campbell told Reuters early on Thursday. "High winds are predicted, but we have not received them yet."
Tubbs is one of nearly two dozen fires spanning eight counties that, raging largely unchecked since igniting on Sunday, have left hundreds of residents unaccounted for.
They have also charred around 170,000 acres of land and destroyed some 3,500 buildings since.
While their cause has not been conclusively determined, they are thought to have been sparked by power lines toppled by gale force winds, and fanned by hot, dry "Diablo" winds that blew into northern California toward the Pacific.
New advisory evacuations were also issued in Sonoma County late on Wednesday for parts of Santa Rosa, the largest city in the state's world-renowned wine country, and Geyserville, an unincorporated town of 800 people.
"The winds are predicted to be very erratic," said county spokesman Barry Dugan. "There will be burst of high gusts that can be ... very unpredictable and difficult when you are fighting a fire and also for residents who we are trying to keep posted."
Wildfires have damaged or demolished at least 13 Napa Valley wineries, a vintners' trade group said on Tuesday.
Around 25,000 people remained under evacuation on Wednesday as the fires belched smoke that drifted south over the San Francisco Bay area, where some residents donned face masks.