The Line fire in San Bernardino County, after burning nearly a month, has surged once again, causing new evacuations Sunday.

Residents in Seven Oaks and the Barton Flats area, including all campgrounds and cabins, were ordered to evacuate due to the immediate threat of the fire.

“Emergency personnel are actively working in the area,” the San Bernardino County Sheriff’s Department said in a post on X.

The fire, which has now consumed 40,219 acres, was still burning actively in Bear Creek on Sunday and producing a lot of smoky conditions because of dried-out fuels, Cal Fire said.

The blaze was sparked Sept. 5 and, as it raged, threatened tens of thousands of structures, eventually damaging at least four and destroying one, according to Cal Fire. Four firefighters have been injured since the fire began.

In early September, an awed resident said the massive cloud caused by the fire looked apocalyptic. “It looked exactly like a nuclear warhead had been set off in the mountains,” said Megan Vasquez.

As of Sunday’s flare-up, firefighters wrestling to gain control of the fire had managed 83% containment.

Fallsvale Elementary School announced Sunday it would close its campus Monday due to the fire.

Angelus Oaks and the Boulder Bay area of Big Bear were under an evacuation warning.

The Bear Valley Unified School District, which includes Fallsvale, announced that other campuses would remain open Monday, although the district was aware of the heavy smoke from the fire and the concerns of families. School officials said they were consulting with local authorities and air quality experts and would continue to monitor the air quality.

The latest update from Cal Fire noted that the fire had been challenging for firefighters due to the steep mountain terrain, and crews were working to build a heli-spot so firefighters could be flown in to access the area.

With temperatures reaching triple digits later this week, Cal Fire noted that humidity had continued to drop. Luckily, forecasters were not expecting significant winds, which would make containing the fire more difficult.

Relative humidity in the fire area was expected to range as low as 12%, with winds gusting to about 15 mph.

Cal Fire said it had strengthened a critical containment line and had at least 10 helicopters working in the fire area.