More than 6,000 firefighters in California's Central Valley continued to battle the largest blaze in the U.S. on Saturday, which burned its way into the history books as the state's fourth-largest conflagration on record.

There was barely a taste of rain on Saturday from thunderstorms that brought wind and rainfall of zero to one-tenth of an inch, forecasters said.

The heat of 100 degrees Fahrenheit (38 Celsius) along with winds up to 25 mph or more in some spots, offered little relief to the firefighters trying to contain the Park Fire, scorching the wilderness terrain some 100 miles (161 km) north of Sacramento, the state capital.

"We had some thunderstorms that just brought us down-drafts, that's a problem," said Christopher Young, a spokesman for the California Department of Forestry and Fire Protection, or Cal Fire. "Lightning is a factor we worry about."

Blazes from the Park Fire, started by an alleged arsonist who pushed a flaming car down a 60-foot gully near Chico, California, on July 24, has since burned more than 400,000 acres (162,200 hectares) or more than 600 square miles, an area larger than the city of Los Angeles.

The 42-year-old man arrested had not entered a plea as of Saturday, but was charged with arson and held without bail, officials said.

More than 560 homes and other structures were destroyed since the blaze started 11 days ago, feeding off of downed timber and tinder-dry grass and brush. The fire was 27% contained on Saturday, officials said.

More than 4,000 people were evacuated in the Park Fire including retiree Jim Young, 65, of Red Bluff, California, where he lived in a trailer home with his dog, a black Labrador Retriever named Sparky.

He and the dog spent the last eight days camped out with some other families in a gravel lot at a wilderness trailhead about 6 miles from his home, worrying every day if it was safe.

"We just found out we can go home," Young told Reuters on Saturday evening. "Our property is safe. So many lost everything. But me and Sparky can go home now."

The rough, wilderness terrain means it takes two to three hours to reach the fire lines, officials said. Some firefighters are being flown to the front lines by helicopters, with some expected to stay there for days with supplies also flown in.

The national wildfire season has had an intense start, raising the risk of stretching firefighting resources too thin. The National Interagency Fire Center has already requested help from firefighters in Australia and New Zealand, who will arrive starting Aug. 7 and deploy to Oregon and Washington.