Shasta County Sheriff Tom Bosenko said they had not yet been positively identified but were believed to be victims identified by relatives on Facebook and in news media reports as James Roberts, 5, his sister Emily, 4, and Melody Bledsoe, 70.
She said the state had experienced considerably more fire activity this year than it did over the same period of time last year, with the worst part of the fire season still to come.
The fire in Santa Rosa in October 2017 destroyed almost 2,700 homes, including in one neighborhood with expensive new subdivisions on a hillside at the edge of the city.
Some 3,400 firefighters on the ground and in helicopters and airplanes battled the 48,300-acre (19,500 hectares) Carr Fire early on Saturday as it ripped through Redding, with a population of 90,000 people, in California's scenic Shasta-Trinity area.
For days, family members had combed evacuation shelters, praying for a sign that Melody Bledsoe and her granddaughter's children had survived the Carr Fire.
The air chokes with the smell of smoke and chemicals, smoldering what's left of people's lives.
The 45-square-mile fire that began Monday tripled in size overnight Thursday amid scorching temperatures, low humidity and windy conditions.
The Philippine Consulate General in San Francisco is also checking the situation of Filipinos in Redding and surrounding areas to determine whether any of them has been affected by the so-called Carr Fire.
The fire broke out on July 23, 2018, which forced tens of thousands of people to flee from their homes. Temperatures were forecast to reach 42.8degC on Saturday, with winds of up to 13kmh, according to the National Weather Service.
Crews are getting control of a small wildfire in California's wine country county of Napa, but two blazes farther north are raging mostly unchecked. A count by The Associated Press found at least 300 of those structures were homes.
By Saturday evening, the fire had grown to 83,800 acres and was only 5 percent contained, according to the California Department of Forestry and Fire Protection.
He also said his family was never told to evacuate. The two fires, burning 30 miles (50 kilometers) apart, started Friday and were threatening more than 350 buildings. Residents in neighboring Benmore Valley were also told to leave Saturday.More news: Facebook stock dives almost 20% on warning of slow revenue growth
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In addition to the Carr Fire, more than a dozen other large wildfires are burning throughout California, stretching resources.
US President Donald Trump on Saturday declared the fire an emergency, authorising federal funds for disaster relief efforts.
All nine fires were set Wednesday in the Idyllwild, Anza and Sage areas about 100 miles east of Los Angeles. It is only 5 percent contained.
Some evacuations were lifted but officials said Yosemite Valley, the heart of tourism in the park, will remain closed until August 3.
There are 89 large wildfires blazing across 14 U.S. states, mostly in the West, according to the National Interagency Fire Center.
Wildfires have so far left charred an estimated 4.15 million acres (1.68 million hectares) of land in the United States this year.
It's now the largest of more than 20 fires burning in California.
Somewhere in the ash was the home of Shyla and Jason Campbell.
About 12,000 firefighters were battling the fires, she said.
"It's huge flames, it's coming up the hill, and everyone's out and we're watching it, then it goes down, and everyone's like, 'Oh it's going out, ' " said Shyla, 32.
The family spent the night at a hotel. He rushed back to his home to try to retrieve possessions but by the time he arrived, authorities had closed the road.
Donna Araiza, founder of the Alyssa Araiza "Wings of Angels" organization for seriously ill children, said Stoke regularly donated to her group, as well as the Make-A-Wish Foundation.