SPOKANE, Wash. — Hundreds of firefighters are working long shifts to slow the Spokane Complex Fire ahead of hotter and drier conditions this weekend.

More than 1,500 firefighters from two dozen states are battling the conflagration, which has damaged or destroyed nearly 850 structures since it ignited Saturday.

Temperatures were expected to climb from the 80s the last two days into the upper 90s later this week with no rain on the horizon.

Still, “tremendous progress” has been made, said Tom Stokesberry, spokesman for the California Interagency Incident Management Team that is coordinating the multiagency response.

The fire has grown by only 2 acres since Monday, and fire lines are being established on the three fires that make up the Spokane Complex. About 67,000 people have been displaced, officials said, adding that the number could climb.

No deaths have been reported.

“If our lines hold through the weekend, I think we’re going to be on the path to not having this fire move anymore,” he said. “But it’s still going to be a long recovery phase.”

The Old Trails and Autumn Lane fires were each 13% contained Wednesday, and the Fairview Fire was 5% contained, according to fire officials. The fires had burned 10,546 acres by Wednesday evening.

Firefighters are embroiled in what Stokesberry called a “search and destroy” mission. Elite Hotshot crews are stationed within acres of one another in an effort to mitigate all hot spots as they emerge, he said.

The crews are sleeping just five to seven hours a night, and they are working 16-hour shifts. Their deployments are typically two weeks before they are replaced by fresh crews, Stokesberry said. Additional support is expected to arrive this weekend.

“It’s trying on them, but they’re here for the long haul,” he said.

Michael Kelly, a spokesperson for the Washington State Department of Natural Resources, said that with more than 800 structures lost, the fire is “likely one of the most destructive in state history.”

The 2023 Grey and Oregon Road fires outside Spokane destroyed 350 structures, Kelly said.

Progress was thwarted this week when 40 drones entered restricted airspace and forced aerial crews to land until flight paths were cleared, Stokesberry said.

“If you fly, we can’t,” he said. “It puts crews at risk. It puts life and property at risk, the infrastructure at risk. It puts everything at risk.”

Drones have interrupted firefighters in the past, including in the Palisades Fire last year. A Southern California man was charged with recklessly operating a drone that crashed into a Super Scooper firefighting aircraft. He pleaded guilty, the U.S. Justice Department said.

It was not immediately clear whether any drone operators have been identified or questioned in connection with the recent incidents. Stokesberry said the skies have remained free of uncrewed aircraft since Monday, which has allowed fire crews to attack from above and below.

A man suspected of arson in one of the fires is expected to be arraigned Thursday.

Aaron Farinacci, 37, who is accused of starting the Old Trails Fire, was charged Monday with first-degree arson. An attorney for Farinacci did not immediately respond to a request for comment after normal business hours Wednesday.

People also started the two other fires, investigators have said, though not necessarily intentionally. The exact causes remain under investigation, officials said. No one else has been arrested.

On Saturday, Paul Child, 64, was driving along railroad tracks in his rural neighborhood northwest of Spokane, he told The Associated Press. He saw a man standing and looking toward nearby trees.

“He was bent over in the brush, acting nervous,” Child said. “You get the feeling this guy’s up to something.”

After they got home, his daughter told him there was a fire, he said.

She called 911 with a description of the man. A responding sheriff’s deputy saw a man matching the description and detained him, according to court records related to Farinacci’s arrest. Officials said the man, identified as Farinacci, was released because a cause had not yet been determined, but he was later arrested and charged.

Alicia Victoria Lozano reported from Los Angeles and Morgan Chesky from Spokane.