REDDING (AP) — An explosive wildfire tore through two small Northern California communities Thursday before reaching the city of Redding, killing a bulldozer operator on the fire lines, burning three firefighters, destroying dozens of homes and forcing thousands to flee.

Scott McLean, a Cal Fire spokesman for the crews battling the blaze, said flames swept through the communities of Shasta and Keswick before jumping the Sacramento River and reaching Redding, a city of about 92,000 people — the largest in the region.

The Carr Fire is “taking down everything in its path,” he said. “It’s just a wall of flames. It’s nonstop.”

Late Thursday, crews found the body of a bulldozer operator who was hired privately to clear vegetation in the blaze’s path, McLean said.

The fire burned over the operator and his equipment, making the man the second bulldozer operator killed in a California blaze in less than two weeks.

Three firefighters and an unknown number of civilians had burns, but the extent of their injuries wasn’t immediately known, McLean said.

“It’s just chaotic. It’s wild,” he said. “There’s a lot of fire, a lot of structures burning.”

He said many people in Redding didn’t seem prepared for the blaze to reach their city.

“When it hit, people were really scrambling,” he said. “There was not much of a warning.”

Traffic out of the city was backed up, with drives that normally take 20 minutes reaching two and a half hours long as residents fled to safety, he said.

Firefighters tried in vain to build containment around the blaze Thursday but flames kept jumping their lines, he said.

“It’s just a heck of a fight,” he said. “They’re doing what they can do and they get pushed out in a lot of cases. We’re fighting the fight right now.”

The 45-square-mile fire that began Monday tripled in size overnight Thursday amid scorching temperatures, low humidity and windy conditions.

Earlier in the day with flames exploding around Whiskeytown Lake, an effort to save boats at a marina by untying them from moorings and pushing them to safety, wasn’t swift enough to spare them all.

Dozens of charred, twisted and melted boats were among the losses at Oak Bottom Marina.

“The boat docks down there — all the way out in the water — 30 to 40 boats caught fire when the fire laid down on top of them last night and burned those up,” said fire Chief Mike Hebrard of the California Department of Forestry and Fire Protection.

In the historic Gold Rush-era town of Shasta, state parks employees worked through the early morning to rescue artifacts from a museum as the blaze advanced.

Wildfires throughout the state have burned through tinder-dry brush and forest, forced thousands to evacuate homes and forced campers to pack up their tents at the height of summer. Gov. Jerry Brown declared states of emergency for the three largest fires, which will authorize the state to rally resources to local governments.

The wildfires have dispatched firefighters to all corners of the state amid an oppressive heat wave.

A huge forest fire continued to grow outside Yosemite National Park. That blaze killed 36-year-old Braden Varney, a heavy equipment operator for the California Department of Forestry and Fire Protection whose bulldozer rolled over into a ravine July 14.

About 100 homes were still under threat in the San Francisco Bay community of Clayton, although firefighters had stopped the progress of a small fire there after one house burned.

Hundreds of miles to the south, winds picked up and sent flames rushing downhill on the flanks of Southern California’s Mount San Jacinto.

Helicopters making water drops and air tankers pouring red flame retardant circled overhead as flames burned both sides of the main road leading to the scenic town of Idyllwild.

The blaze erupted Wednesday and quickly turned into a wall of flame that torched timber and dry brush. In a matter of hours, the so-called Cranston Fire grew to 7.5 square miles (19 square kilometers).

About 3,000 residents were under evacuation orders Thursday in Idyllwild and several neighboring communities.

The Cranston Fire was the largest of at least five police believe were purposely set by a man whose car was spotted at the starting point of the blaze in Riverside County, officials said.

Brandon McGlover, 32, of Temecula was booked on suspicion of five counts of arson, state fire officials said.

The heart of Yosemite National Park remained empty the day after campers and hotel guests were evicted so firefighters could try to keep the state’s largest fire from entering the park nearly two weeks after it was sparked.

The closure was heartbreaking for travelers who mapped out trips months in advance to hike and climb amid the spectacular views of cascading waterfalls and sheer rock faces.

Daina Miller of Tucson, Arizona, had wanted to visit Yosemite for years, but instead her family spent a few hours breathing foul-smelling smoke Tuesday before retreating to their RV for the night. The next morning, they left for Los Angeles.

“You go there and expect the fresh air and it was the total opposite of that,” she said Thursday.

The closure through at least Sunday led to at least 1,000 campground and hotel bookings being canceled, park spokesman Scott Gediman said.

Officials emphasized Yosemite wasn’t in imminent danger from the Ferguson Fire, which grew to more than 67 square miles in steep timber in the adjacent Sierra National Forest. The fire was just 25 percent contained.

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