California officials have ordered an entire city to evacuate as “conditions have worsened” in the wildfires that have killed 23 people.
All residents of Calistoga were directed to leave the area on Wednesday evening, Napa County officials said.
About 60 prison inmates have joined hard-pressed firefighters in battling the fast-moving blazes, the state fire chief says.
Among the areas scorched by the 22 blazes are marijuana farms.
In Wednesday evening’s evacuation of Calistoga, in Napa County, all 5,000 residents were told to leave and police blocked traffic from approaching the area.
And traffic quickly clogged the exits from Boyes Hot Springs in Sonoma County as that community was also told to evacuate the advancing wall of flame.
“It’s going to continue to get worse before it gets better,” state fire Chief Ken Pimlott said.
He warned that the death toll could rise further.
“We are still impacted by five years of drought. These fires were driven by the critically dry fuel bed. We are literally looking at explosive vegetation,” he added.
The devastating wildfires, which brought wind gusts of up to 45mph (72km/h), have destroyed at least 3,500 buildings and homes.
Slide the button to see how a Santa Rosa community was devastated
Renewed high winds are fanning the “catastrophic” blazes, said state fire officials, which are spreading unpredictably in their fourth day.
Firefighters are going door to door in the state’s wine-producing region, evacuating those who are left behind ahead of the next wave of blazes.
Investigators are also searching shelters to locate nearly 300 missing people, though police say they may have scattered amid the chaos.
The fires are among the deadliest in California’s history and have sent smoke as far south as San Francisco, about 60 miles (100km) away.
More than 200 fire engines and crews are being rushed to California from the rest of the US, officials said.
Mr Pimlott said 73 helicopters, 30 air tankers and nearly 8,000 firefighters were currently battling the blazes.
The fires have reduced entire neighbourhoods in the city of Santa Rosa, a city of 175,000 people, to ash.
At least 13 of the deaths have occurred in Sonoma County, officials say. Some 25,000 people across the county have been evacuated and 40,000 homes are without power.
Six people have died in Mendocino County, two in Yuba County and two in Napa County, officials told told the Los Angeles Times.
Cannabis plantations in fire-scorched Mendocino County could lose millions as many are uninsured, according to Nikki Lastreto of the local industry association.
Marijuana farmers cannot insure their businesses since federal law bans the drug.
Though recreational cannabis was legalised in the state in 2016, California’s retail market does not open until January 2018.
This means some farmers who have invested millions may be left without a business once the smoke clears.
At least four wineries have suffered “total or very significant losses”, Napa Valley Vintners said, with nine others reporting some damage to buildings or vineyards.