A YOUNG boy pleaded for rescue before he died along with two others in a California fire, his anguished great-grandfather recounted on Monday, while other shaken survivors told of their flight from a “tornado” of fire.

The worst blaze, in the US state’s north, has killed six people since Thursday, including a 70-year-old woman and her two great-grandchildren aged four and five. They perished when flames swallowed their home in Redding.

Local media identified the victims as Melody Bledsoe and the children, Emily Roberts and James Roberts, nicknamed “Junior.”

“I talked to Junior on the phone till he died,” Melody’s husband Ed Bledsoe told CNN, recounting the last words of the boy, his sister, and Bledsoe’s wife.

“He said ‘Come and get me, the fire’s comin’ in the back door. Come on grandpa,’ Bledsoe said, his voice choking.

All three told them that they loved him, before Bledsoe assured the boy: “I’m on my way.” He couldn’t get there in time to save them.

The Carr Fire around Redding is the worst of several large-scale blazes that have turned close to 200,000 acres into ashen wasteland.

“I’ve been a lifelong resident of this community, and I’ve never seen a fire with such destruction here in this area ever before,” Shasta County Supervisor Leonard Moty said of the Carr Fire.

About 38,000 people have been evacuated in Shasta County due to the Carr Fire, officials said. US President Donald Trump on the weekend approved California’s request for federal help to fight the blaze and assist evacuees.

A thick smoke haze covered a large part of northern California, severely limiting visibility and contributing to breathing problems.

According to the California Governor’s Office of Emergency Services (Cal OES), 12,000 firefighters from as far away as Florida and New Jersey have deployed across the state.

A firefighter identified as Brian Hughes died on Sunday while battling the Ferguson Fire near Yosemite National Park, a major tourist attraction partially closed because of the fire.

Hughes “was struck and killed by a tree” while fighting the blaze, the Sequoia and Kings National Parks Service said.

The remains of a person who ignored Carr Fire evacuation orders was found in a burnt-out residence on Sunday, said Shasta County Sheriff Tom Bosenko.

Two firefighters were killed late last week battling the Carr blaze, and another firefighter died days earlier working at the fire around Yosemite.

Seven other people are reported missing, Sheriff Bosenko said, adding that 600 National Guard soldiers had been deployed for support duties such as roadblocks.

The Carr fire covers more than 95,000 acres and was just 17 per cent contained, Cal Fire, the state’s Department of Forestry and Fire Protection, said late on Sunday.

Nevertheless, authorities “are very encouraged with the fire status” in Redding, said Cal Fire incident manager Bret Gouvea.

“We’re feeling a lot more optimistic … as we’re starting to make up some ground instead of being on the defensive,” he told reporters.

Gouvea, however, said he was wary of unpredictable weather.

The National Weather Service forecast another very hot day on Monday, with a high near 38 degrees celcius, widespread smoke and a calm wind.