Hourly Air Quality Index (AQI) for the Northwest U.S., 23 August 2015. Graphic: AirNow.gov

By Donna Blankinship and Brian Skoloff
23 August 2015 OKANOGAN, Washington (AP) – The massive cloud of smoke began to lift over Washington wildfires on Sunday. But as air quality improves, the fire’s behavior could become more erratic and intense, fire officials said. “It’s like a flue opening in a fireplace,” said Suzanne Flory, spokeswoman for the U.S. Forest Service and the Rocky Mountain Incident Management Team. “Smoke serves as a cap on the fire.” The Okanogan Complex of wildfires was measured at 374 square miles as of Sunday morning. Once the smoke lifts, humidity drops, heat rises and fires can flare up. Flory said they would not know until Sunday night or early Monday how much the fire had grown on Sunday, but as of late afternoon, fire activity had been relatively quiet. Visibility and air quality improved Sunday. The complex of fires was estimated to be about 10 percent contained as of Sunday morning, fire spokesman Dan Omdal said. […] Air quality, which has been dangerously bad, will also improve when the smoke cloud lifts, but firefighters won’t be able to take a breather. “We tell firefighters, if you see blue sky, heads up,” Flory said. [more]

Smoke lifting Sunday over Washington fires, but fire growth remains calm so far