Flames raging in California's scenic Shasta-Trinity area erupted into a firestorm that jumped across the Sacramento River on Friday and swept into the western side of Redding, home to about 90,000 people, forcing residents to flee.
Firefighters and police "went into life-safety mode," hustling door to door to usher civilians out of harm's way, said Scott McLean, a spokesman for the California Department of Forestry and Fire Protection (CalFire).
Streets in the town were all but deserted, with thick, sickly-brown smoke filling the air, and plumes of smoke rising to the west.
Gale-force winds on Thursday night created a fire "tornado" said CalFire Director Ken Pimlott.
"This fire was whipped up into a whirlwind of activity, uprooting trees, moving vehicles, moving parts of roadways," Pimlott told a news briefing.
Such highly erratic, storm-like wildfires have grown commonplace in the state, Pimlott said.
"These are extreme conditions, this is how fires are in California," he said. "We need to take heed and evacuate, evacuate, evacuate."
California has had its worst start to the fire season in a decade, with 289,727 acres burned through Friday morning, according to National Interagency Fire Center (NIFC) data.
Governor Jerry Brown requested emergency federal assistance to prevent an "imminent catastrophe" as Shasta County tried to find supplies and water for 30,000 evacuated residents and care for horses and cattle rescued from ranches and farms.
CalFire reported 65 structures destroyed by the blaze, but McLean called that tally a "placeholder" figure that would grow significantly, with the number of homes lost likely to run into "the hundreds" as the scope of devastation was fully assessed.
CURTAIN OF SMOKE
The fire had scorched 18,000ha by Friday and was just 3% contained as ground crews, helicopters and airplanes battled the flames for a fifth day.
High temperatures and low humidity were expected for the next seven to ten days, said Pimlott. "This fire is a long way from done."
The blaze was one of nearly 90 large fires burning nationally, most of them in the West. One of those prompted the closure of much of California's Yosemite National Park.
Wildfires have blackened an estimated 1.68 million hectares in the United States this year. That was well above average for the same period over the past 10 years but down from 2.13 million hectares in the first seven months of 2017, NIFC reported.
The blaze in Redding, about 240km north of Sacramento, on Thursday killed a bulldozer operator working with fire teams to clear brush around the fire.
A member of the Redding Fire Department was also reported killed on Friday. A Redding hospital said it had treated eight people, including three firefighters.
