After a brief reprieve with calmer winds and cooler temperatures, the wildfires in the western U.S. state of California grew overnight Wednesday to 22, as officials said the death toll rose to 17.
Cooler weather and moist ocean air had helped the hundreds of firefighters battling the blazes in the northern part of the state, which have burned nearly 50,000 hectares (123,500 acres) of land and at least 3,500 homes and businesses, and have caused more than 20,000 people to evacuate their homes. Several thousand have gone to temporary shelters.
"We are expecting some extreme fire behavior and growth of our incidents currently, and that is going to lead us to challenges," Napa County Fire Chief Barry Biermann said Wednesday. "The good news is we are starting to get some additional resources coming in throughout the state."
Evacuations continued throughout the state overnight.
"My advice to you is, 'Go,' " Sonoma County Sheriff Robert Giordano said at a news conference Wednesday, encouraging residents to flee even before mandatory evacuations. "This is still a very serious event."
Among the areas affected are Napa and Sonoma counties north of San Francisco that are home to dozens of wineries that draw tourists from around the world.
Giordano said more than 500 people had been reported missing in Sonoma County. But he said that many of these might simply be struggling to get in touch with family members and authorities, with 73 cell towers down across the state.
Governor Jerry Brown declared a state of emergency in eight counties and thanked the federal government for a fast response in offering aid to the state.
U.S. President Donald Trump approved the funding Tuesday.
"Napa has been hit so hard — and Sonoma, as they deal with the tragic loss of life and property to devastating wildfires," Trump said at a White House reception.
Authorities said they did not know what started the fires. California commonly has wildfires in the late summer and early fall that spread with the help of strong, dry winds.