SHASTA-TRINITY NATIONAL FOREST, Calif. (AP) — Truckers abandoned big-rigs and motorists screamed in fear as they came dangerously close to an explosive wildfire that shut down about 45 miles of a major California interstate near the Oregon border that authorities were desperately trying to reopen.

In a video, a passenger in a vehicle screams: "Oh my God, I want to go!" as nearby trees burst into flames.

"I can't breathe," the woman says, sobbing. "Please, guys, come put it out."

The fire erupted Wednesday afternoon in a rural area and devoured timber and brush on both sides of Interstate 5 as it nearly tripled in size overnight, officials said Thursday.

Elsewhere in the state, a fire raging in the Sierra Nevada had grown to more than 7 square miles (18 square kilometers) after shutting down stretches of U.S. 395, State Route 108 and the Pacific Crest Trail along the eastern spine of California.

The Marine Corps Mountain Warfare Training Center, campgrounds and other areas were evacuated Wednesday. Ranchers were told to prepare to move livestock out of the area in Humboldt-Toiyabe National Forest.

The two fires Thursday were raging just weeks after a blaze in the Redding area killed eight people and burned some 1,100 homes in a frightening start to the fire season.

California's insurance commissioner said Thursday that victims of that fire and one in the Mendocino area — the two largest blazes in the state so far this year — have filed more than 10,000 claims so far totaling $845 million.

The two fires destroyed or damaged a combined 8,800 homes and 329 businesses.

"The worst may be yet to come," Commissioner David Jones warned at a San Francisco news conference, noting that California wildfires are typically more destructive after Sept. 1.

The blaze Thursday along Interstate 5 has blackened 23 square miles (60 square kilometers), prompting mandatory evacuations. It was moving rapidly but was still far from any large towns.

Officials from a number of agencies were meeting Thursday to determine if they can reopen the highway, a key route for commercial trucks, California Highway Patrol Officer Jason Morton said.

The highway runs north from the Mexico border through California, Oregon and Washington state to the border with Canada.

The scattered homes and cabins in and around Shasta-Trinity National Forest were under evacuation orders, from the community of Lakehead north to the Siskiyou County line, said Chris Losi, a spokesman for the forest.

"It isn't a lot of people," he said.

The blaze was human-caused, officials said, without indicating whether it was arson or an accident.

About 17 big-rigs were abandoned along the interstate and at least four caught fire, Lt. Cmdr. Kyle Foster of the California Highway Patrol's Mount Shasta office told the Los Angeles Times. At least two trucks were partially melted.

U.S. Forest Service workers helped the driver of one flaming truck to safety. Truckers, firefighters and others aided more drivers.

"There's vehicles scattered all over," Brandon Vaccaro of the California Department of Forestry and Fire Protection told the Redding Record Searchlight. "Whatever occurred here was probably pretty ugly for a while."

About 45 miles (72 kilometers) of I-5 were closed in both directions, Losi said. The blaze also delayed Amtrak's Coast Starlight train service between Sacramento and Oregon.

The city of Dunsmuir, with about 1,500 residents, was about 15 miles (24 kilometers) from the flames. Residents were urged to be prepared to leave if the fire threatened.

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Elias reported from San Francisco.

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