The blaze remained unpredictable, said Chris Anthony, a division chief with the California Department of Forestry and Fire Protection (Cal Fire).
Authorities also issued evacuation orders in Napa County, famous for its wine, when a fire destroyed eight structures.
At least seven people were still missing in Shasta County, California, as shifting winds, dry fuel and steep terrain helped the monstrous fire engulf nearly 100,000 acres by Sunday night, authorities said.
A tearful Sherry Bledsoe confirmed the deaths of her grandmother, Melody Bledsoe, and her children, James Roberts, 5, and Emily Roberts, 4.
"Grandma did everything she could to save them", Woodly wrote.More news: Greece mourns as death toll from wildfires reaches 81
Bledsoe said even though the family was not told to evacuate, he feels more guilty than angry.
"Fires don't stop for sleep so this is a 24-hour battle for the American firefighting forces and extra people with the specialised skills that they need will help a lot."
The Carr Fire is among 17 major fires blazing in California with more than 200,000 acres burning, the National Park Service told a news conference. The fires have destroyed six homes and threaten 10,000 others. The so-called Carr Fire, about 150 miles north of Sacramento, has grown to almost 150 square miles and is only 17 percent contained. There were door-to-door notifications made in the area, he said.
A Sequoia and Kings Canyon National Park firefighter, identified as Capt. Brian Hughes, died fighting the Ferguson Fire after he was struck and killed by a tree Sunday, according to a statement from the Sequoia and Kings Canyon National Parks.
Ed Bledsoe, who lost his wife and great-grandchildren, told CNN's Dan Simon he was out running errands when flames engulfed his home.More news: 2nd firefighter dies battling California wildfires
The fire started Monday, its origin traced to the "mechanical failure" of a vehicle in Whiskeytown, which is about 10 miles northwest of Redding, officials said.
"It's a hard fire to deal with", Austin said, noting the weather was hot and the terrain rugged. "They're that important to me", Bledsoe said. So she and her mother decided to make breakfast burritos for him and other hungry CalFire crews who were coming off the night shift after trying to contain the Carr Fire in Redding.
The nearby community of Keswick, with a population of about 450, was reduced to cinders.
And 150 fire engines were on the way from as far away as Florida, officials said Sunday.
On social media, residents posted photos of wandering dogs and horses left behind by owners in the fire-stricken region, a popular fishing destination that lies just south of California's largest man-made lake.
The Carr Fire, in particular, began as a manageable blaze burning through a few thousand acres before it quickly spread to 20,000 acres last week.
U.S. firefighters have worked to put out 89 large fires, which have burned more than 3,760 square kilometres over the peak summer period.More news: Nick Jonas And Priyanka Chopra Are Engaged
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