Firefighters gained further ground over the weekend against three Southern California wildfires as authorities in northern Nevada lifted the last of evacuation orders for all homes Sunday.

More than 8,000 personnel combined are battling the three biggest fires burning in the state, all ignited during a triple-digit heatwave at the start of the month.

The largest blaze is the Bridge Fire at 85 square miles, which exploded dramatically through the Angeles National Forest east of Los Angeles at the start of the week. It has torched at least 49 buildings and forced the evacuation of 10,000 people. The fire was 9% contained Sunday morning, with firefighters gaining 4% overnight.

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Officials said Sunday the focus continues to be on the northwest flank, where the fire is the most active, but upcoming rain and humidity will aid firefighting efforts.

“That's not gonna stop this fire, what that is gonna allow is ... operation folks to go out there and be able to get that line constructed,” said fire behavior analyst Garret Hazelton on Saturday.

The Line Fire in Southern California

The Line Fire, which grew slightly overnight to 60 square miles in the San Bernardino Mountains, was 36% contained Sunday.

Officials said it was active in the early morning due to a dry air mass in higher elevations, but cool weather conditions prevailed across the fire area. Light rain was possible late Sunday and into Monday.

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Authorities have said a delivery driver purposely started the Line Fire in Southern California on Sept. 5.

Arson-related charges have been filed against Justin Wayne Halstenberg, who is accused of starting the Line Fire. He is due to be arraigned on Monday, according to the San Bernardino County District Attorney’s Office. Halstenberg’s mother, Connie Halstenberg, told the Los Angeles Times that her son “did not light that fire.”

The Airport Fire in Southern California

The Airport Fire in Orange and Riverside counties remained at 37 square miles and 19% containment as of Sunday.

“We’re being helped by the weather and that weather will continue for a couple of days so we’re making good progress," said Orange County Fire Authority Operations Section Chief Albert Ward.

Firefighting efforts are expected to get a significant boost from thick fog and high humidity Sunday night, and from cooler temperatures and light rain Sunday and Monday, according to the fire authority.

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Crews were able to gain access to an area previously blocked by a rock slide. However, the southern edge of the fire is still marked by “very rugged inaccessible country” that will require helicopters to bring crews in or a long hike, Ward said Sunday.

Despite favorable weather, there is still fire risk above 4,000 feet in elevation, which remains dry. Smoldering vegetation up high can roll downhill and ignite unburned vegetation, the fire authority said.

The Davis fire in northern Nevada

In northern Nevada, Washoe County fire officials say evacuations will be lifted Sunday for all homes — the last of nearly 20,000 evacuees.

The Davis fire was estimated at 77% containment on Sunday.

Officials said the fire now is classified as being in a state of mop-up with many restoration and repair projects underway. More than 600 personnel are currently working the wildland blaze that destroyed 14 homes and burned through nearly 9 square miles of timber and brush along the Sierra Nevada’s eastern slope near Lake Tahoe.