When the flames flare up, firefighters get to work on the ground, digging a fire line around the blaze to contain it.
"The term containment means there is a fire line constructed to mineral soil or using roads and other natural barriers such as water or rocks around the fire," Forest Service Fire Training and Safety Manager Tim Hoiness aid Monday.
Fire lines are trenches dug to create a "fuel break" around the fire -- they stop it from spreading. For example, the Sunnyside Turnoff fire burning in Warm Springs is 100% lined, and of that, crews believe 95% of that will hold. So it's 95% contained.
"So you can have a containment line around the fire but have areas within the fire parameter within that fire line that could still burn -- and burn very hot," Hoiness said.
Sometimes the percentage is a rough guess by firefighters -- and if the fire starts acting up, the containment number can go down.
"You don't always know. Sometimes you have to guess if it's too smoky," Hoiness said. "Again, that could fluctuate up and down. If the fire is moving day after day after day and you are losing ground, your (containment) percentage might drop."
Even when the fire reaches 100 percent containment, it does not mean the fire is out.
"Once containment is established at 100 percent, there can still be a lot of smoke from the area. It doesn't mean the fire is controlled or out by any means, it just means there is a line around it," Hoiness added.
Once a fire is fully contained, firefighters work on "controlling" it by battling it inside the containment line. A controlled fire has no risk of expanding beyond the fire line.
Contain, control, out. Eventually the fire will run out of fuel -- or could finally be snuffed when the seasons change.
"Containment and control will come, but it may take weeks, months -- it may even be when the snow has fallen that the fire is declared as out," Hoiness said.