California wildfires: One dead as fire crews battle to contain blaze

An explosive wildfire killed one person and left several others with burns after it tore through communities in northern California.

Flames swept across the rural areas of Shasta and Keswick on Thursday, before jumping the Sacramento River and reaching Redding, a city of around 92,000 people.

Late on Thursday, firefighters found the body of a bulldozer operator who was hired privately to clear vegetation in the blaze's path, CalFire spokesman Scott McLean said.

“[The fire is] taking down everything in its path,” he said. “It's just a wall of flames. It's non-stop.”

Three firefighters and an unknown number of civilians suffered burns during the fire, but information on the extent of their injuries was not immediately known.

“It's just chaotic. It's wild,” Mr McLean said: “There's a lot of fire, a lot of structures burning.”

The 45-square-mile fire that began on Monday tripled in size overnight on Thursday amid scorching temperatures, low humidity and windy conditions.

Wildfires throughout the state have burned through tinder-dry brush and forest, forced thousands to evacuate homes and forced campers to pack up their tents at the height of summer.

Governor Jerry Brown declared states of emergency for the three largest fires, which will authorise the state to rally resources to local governments.

Close to the town Idyllwild in southern California, helicopters continue to make water drops and air tankers pour red flame retardant on a blaze that started on Wednesday and now covers 7.5 square miles.

About 3,000 residents were under evacuation orders Thursday in the town and several neighbouring communities.

The blaze, which has been named Cranston Fire, was the largest of at least five police believe were purposely set by a man whose car was spotted at the starting point of the blaze in Riverside County, officials said.

Brandon McGlover, 32, of Temecula has been arrested on suspicion of five counts of arson, state fire officials said.

Meanwhile, Yosemite National Park remained empty the day after campers and hotel guests were evicted so firefighters could try to keep the state's largest fire from entering the park nearly two weeks after it was sparked.

Officials insisted Yosemite wasn't in imminent danger from the Ferguson Fire, which grew to more than 67 square miles in steep timber in the adjacent Sierra National Forest. The fire remains only 25 per cent contained.

Additional reporting by AP