Redding, California (CNN) The Carr Fire raging in Northern California is so large and hot that it is creating its own localized weather system with variable strong winds, making it difficult for experts to predict which way the blaze will spread.
At least 19 people were still reported missing in Shasta County, California, officials said at a community meeting Monday evening, after shifting winds, dry fuel and steep terrain helped the monstrous fire engulf more than 103,000 acres.
The fire has claimed six lives, including a firefighter and bulldozer operator working to extinguish the blaze.
Authorities have received 48 missing person reports but 29 people have since been found safe, according to Shasta County Sheriff Tom Bosenko.
The fire, which started a week ago, has burned 103,772 acres and is just 23% contained, according to the California Department of Forestry and Fire Protection, known as Cal Fire. It has scorched an area bigger than the size of Denver.
Flames have destroyed at least 966 structures in the area, making it one of the top 10 most destructive wildfires in California history. In fact, seven of the 12 most destructive fires have happened since 2015.
"We are seeing more destructive, larger fires burning at rates that we have historically never seen," said Jonathan Cox, Cal Fire regional battalion chief.
More than 3,300 fire personnel are battling the flames with more than 330 engines and 17 helicopters, Cal Fire reported.
The fire began July 23 when a vehicle suffered a mechanical failure, officials said. Firefighters had been making progress containing it until Thursday night, when it began to quickly spread.
Wildfires like this can get so hot they make pyrocumulus clouds, formations that look like mushroom clouds and can be seen for miles.
Cumulus clouds are usually formed when the sun heats the ground, sending warm air up, where the air cools and condenses to form a cloud. In a wildfire, heat from flames forces the air to rise quickly. Water inside trees and other plants evaporates. The added moisture condenses in the cooler air above.
The clouds look and act like thunderstorms. They can produce lightning and powerful winds in different directions, further complicating efforts of firefighters.
Sometimes, they even contain enough moisture to become a type of cloud that can produce rain -- possibly even putting out the blaze.
High temperatures, low humidity and increased winds are all in the forecast, setting the stage for more explosive fire behavior, Chris Harvey with the Cal Fire Incident Management Team said Sunday.
The National Weather Service also warned that forecast conditions would worsen the situation.
"A dangerous heat wave will continue from California to the Pacific Northwest early this week. Triple-digit heat combined with dry humidity will only exacerbate the ongoing wildfire situation in California," it said on Twitter.
CNN meteorologist Haley Brink said no rain is in the forecast this week.
"Winds in the area of the fires will be locally gusty, with gusts up to 25 mph. The fires are likely to generate their own winds, which could be stronger at times," she said. "Elsewhere across Central and Southern California the story remains similar. Temperatures will remain 5-10 degrees above average for the region, and dry/drought conditions will continue with little to no rain expected throughout the week."
The six deaths caused by the erratic flames include 70-year-old Melody Bledsoe and her great-grandchildren, 4-year-old Emily Roberts and 5-year-old James Roberts.
The three had been missing since Thursday when their house was overcome by flames. Family members confirmed Saturday that they died.
"With a heavy heart we are sad to inform you all that Mel and the great-grandbabies were confirmed to be in the home," the family said on a GoFundMe page.
In those final minutes, unable to get to his wife and their great-grandchildren, Ed Bledsoe was able to get through on the phone.
Bledsoe broke into sobs as he described speaking to his family by phone as he was rushing to try to save them.
"He just kept saying 'Grandpa, come and get me," Bledsoe said, referring to 5-year-old James. "'The fire's coming in the back door. C'mon Grandpa.' I said 'I'm right down the road.'"
Another person was found dead after a fire consumed another house, Bosenko said Sunday.
"This fire is scary to us. This is something we haven't seen before in the city," Redding Police Chief Roger Moore told reporters Friday night.
Redding Police Sgt. Todd Cogle said authorities are "finding that there are a lot of communication issues" making it hard to locate residents.
"We spoke with several people who left their cell phones at their residences and in this day and age people don't remember people's phone numbers," Cogle said.
As the fire neared his home outside the Redding city limits last week, Josh Lister hosed down his house and left his hose on the roof running.
His wife, Sarah, had already left with their two young children, a 16-month-old son named Gage and 6-year-old Kaya.
But Lister, who owns a painting and restoration business, grew worried because there was only one entrance and exit to his neighborhood.
He saw the fire in the distance.
"I didn't want to get trapped in there," he said.
As he rushed out of his home, Lister said he left his wedding ring on the vanity in the bathroom, and thousands of dollars of tools and equipment.
"It looked like an atomic bomb went off," he said of damage to the home.
"After the fact, we got a few pictures .... from friends, but it was a firestorm when we left," Lister said.
The Listers have been staying in a hotel since the fire.
"Our house was in a great, awesome neighborhood, great neighbors," Lister said.
Only charred remnants remained of the peaceful life in their home in the rustic foothills neighborhood: Charred bicycles. A chimney still standing in the rubble.
At least two people died fighting the fire, and several others have been hurt.
Jeremy Stoke, a fire inspector with the Redding Fire Department, died Thursday, the Redding firefighters union said.
Stoke, who joined the Redding Fire Department in 2004, was killed while assisting with evacuations, the union said.
A private-hire bulldozer operator, who was not identified, also died Thursday while battling the fire.
Three Marin County firefighters were treated last week for burns to the ears, hands and face after they encountered a "sudden blast of heat" from burning vegetation. Engineer Scott Pederson and firefighters Tyler Barnes and Brian Cardoza have been released from a hospital, the fire department said Friday in a statement.
A fourth firefighter was being evaluated at the UC Davis Burn Center, the statement said.
Eight people were treated for respiratory and burn-related injuries at Mercy Medical Center in Redding, a hospital spokeswoman said Friday morning.
In addition to the Carr Fire, more than a dozen other large wildfires are burning throughout California, stretching resources.
The Cranston Fire near San Bernardino has burned more than 13,130 acres and is 57% contained.
A man accused of setting several fires in Riverside County, including the Cranston Fire, was arrested last Wednesday, authorities said.
The Ranch and River fires in Mendocino County have collectively scorched more than 30,000 acres, Cal Fire said.
The Ferguson Fire in Mariposa County has burned more than 56,000 acres and is 30% contained. The fire has prompted the closure of the most iconic areas of Yosemite National Park, which will reopen to all visitors August 3, officials said.
Fire officials said Monday they hope to lift evacuation orders to let residents back into their homes.
"We have not lost current homes which people are living in which is a testament to the aggressive attack. The fire continues to burn through a large wilderness area," said Doug Binnewies, the Mariposa County sheriff and coroner.
A Sequoia & Kings Canyon National Park firefighter, identified as Capt. Brian Hughes, 33, died fighting the Ferguson Fire after he was struck and killed by a tree Sunday, according to a statement from the Sequoia & Kings Canyon National Parks.
"Hughes was with the Arrowhead [Interagency] Hotshots for four years and will be dearly missed by everyone at the parks," the statement read. "We grieve his loss."
"Hotshot teams are a tight-knit close group that really care for each other and Brian facilitated that caring and connection. He kept that team in strong unity," said Woody Smeck, superintendent of Sequoia & Kings Canyon National Parks. "He was their pillar of strength. He had a bright future ahead of him, gone way too soon."