Although the Archer Mountain Fire was declared fully contained Wednesday morning, and all evacuations lifted, firefighters will continue working in the area for several days.
Typically, when a fire is declared “contained,” it means fire managers think the perimeter around the fire, whether fire lines or natural breaks in vegetation, are secure enough the fire won’t spread past them, said Nancy Marvin, a spokeswoman for the state Department of Natural Resources.
The fire is not “out,” she said.
She couldn’t say precisely what the firefighters on Archer Mountain will be doing, since there are parts of the fire so steep and rocky it would be unsafe for firefighters to go there, and have nothing that can significantly burn.
But once wildfires are considered contained, she said, firefighters begin working deeper into the perimeter of the fire, conducting what’s called mop-up.
That means digging up hot or smoking spots and dousing or moving burning limbs and vegetation deeper into the fire area to, in essence, make a wider fire line.
“What they do is they do the mop-up, and they also do patrol for a little while, so they make sure nothing’s smoking in the area,” she said.
During and after that phase, other firefighters might patrol the area to watch for smoke or new fire.
“They’re going to do mop-up for probably another four or five days,” she said. “Just because it’s contained doesn’t mean our work is done.”
Officials believe the fire started as a spot fire from the Eagle Creek Fire on Sept. 5 when an ember jumped the Columbia River and ignited the blaze. It grew to 260 acres, or about a half a square mile, before firefighters brought it in check.
The Eagle Creek Fire started Sept. 2, after a Vancouver teen allegedly lit a firework in the area, and has burned 35,636 acres (about 57 square miles) south of Cascade Locks, Ore.
Fire managers said Wednesday afternoon the fire was 13 percent contained, and estimated the fire would be fully contained by Sept. 30.
Fires are only declared “out” after extensive mop-up, Marvin said, and every landowner and fire manager is comfortable saying there’s no significant heat left.
“Somebody will be keeping an eye on it until everybody’s comfortable,” she said. “It’s not as if we’re just going to walk away.”
In the case of larger fires, it takes “season-ending” weather, which typically means several days of rain or snow, before they’re extinguished.
The Eagle Creek Fire is one of those fires, she said.
Now that the Archer Mountain Fire is contained, the management team at the Eagle Creek Fire will take over.
Fire managers there said the forecast calls for cooler temperatures over the next few days, and the potential for significant precipitation early next week.