Tens of thousands of Californians fled their homes in the Napa and Sonoma wine regions in the face of wildfires as a new blaze in the north of the state killed three people.
Under an orange sky and a sweltering heatwave, some of Napa Valley's best-known vineyards were consumed by an out-of-control blaze that raced through more than 14,000 hectares, said state fire agency Cal Fire.
Celebrated wineries such as Chateau Boswell and part of Castello di Amorosa went up in smoke, while there was a significant loss of buildings on the fringes of Santa Rosa - neighboring Sonoma County's largest town, said fire chief Tony Gossner.
About 320 kilometers north, three people perished in a "very fast-moving, very fluid, very hot" fire in Shasta County, said Sheriff Eric Magrini.
The fires prompted authorities to order more than 35,000 residents to move out, with thousands more poised to flee, as "explosive fire growth" burned through dry vegetation and difficult mountainous terrain, officials said.
The causes of the fires are still being investigated.
Calistoga, a picturesque community at the top of the Napa Valley known for hot springs and as a launchpad for wine tours, has largely been evacuated.
CeeBee Thompson spent sleepless hours watching flames in the distance and packing her car as Calistoga's recently installed warning sirens sounded twice during the night. "We could see flames shooting up all night long," Thompson said. "The only thing we have left to do is put the cats in the car."
The inferno is threatening communities in Napa and Sonoma, still reeling from devastating wildfires in 2017 when 44 people died and thousands of buildings were razed.
California has been battling massive wildfires for months, stoked by dry conditions, strong seasonal winds and high temperatures. On Monday winds gusting up to 90km/h sent embers flying. The new conflagrations come during a record season, with five of the state's six biggest wildfires in history burning. AGENCE FRANCE-PRESSE