The massive Copper King Fire burning near Thompson Falls continues to grow and spew smoke across Northwest Montana as firefighters work to corral it.

The fire has burned almost 26,000 acres and is 20 percent contained.

“We’ve had trouble with spot fires,” said Mike Cole, information officer with the Northern Rockies National Incident Management Team.

The largest spot fire currently has burned 70 acres, Cole said.

The area was under a red flag warning Tuesday, with hot and dry conditions resulting in more active fire behavior, particularly in the Munson Creek and Weeksville Creek drainages.

“We still have a lot of fire lines to construct,” Cole said. “This is going to be a long-term event even if we get a line all the way around it.”

Crews completed burnout operations in steep terrain to reduce pockets of unburned fuels where firefighters can’t be stationed.

Evacuation notices remain in effect. Forty-five residences have been evacuated east of Thompson Falls, and another 130 homes are in pre-evacuation status.

“That means residents should get their stuff ready to go in a moment’s notice,” Cole said.

On Monday alone, aerial resources dropped 220,000 gallons of water and 22,000 gallons of retardant on the fire.

The firefighting force assembled for the Copper King Fire includes 840 people, with 21 crews, nine bulldozers, eight helicopters, 59 engines and 26 water tenders.

The fire continued to spread smoke widely across Northwest Montana.

Although the Flathead Lake area received smoke on Tuesday, Thompson Falls bore the brunt. Air quality reached “very unhealthy” levels in Thompson Falls.

The area closed around the Copper King Fire encompasses about 80 percent of Hunting District 122.

The closure will affect hunters as the mountain grouse season opens Sept. 1, archery season opens Sept. 3 and black bear season opens Sept. 15. Hunters will not be able to access the area.

Separately, lightning ignited five small wildfires in the upper elevations of the Swan and Mission mountains. Flathead National Forest spokeswoman Janette Turk said Tuesday that none of the fires pose a threat to any structures, but a crew of smokejumpers worked with a pair of helicopters throughout the day to suppress one of the fires burning about 15 acres near Upper Cold Lake in the Missions.

She said the forest also has requested a 20-person crew to suppress the fire ahead of a cold front forecast to potentially bring more gusty conditions Wednesday.