The southern Willamette Valley's air remained smoke-free Tuesday as smoke from fires in Southern Oregon and Northern California held to the upper atmosphere.
Also, the 116-acre Staley Complex Fire near Oakridge didn't flare up much, and generated relatively little smoke, authorities said.
Broad bands of smoke from large fires in Northern California and at the Oregon-California border continue to waft northward, satellite images on Tuesday showed.
But the plumes are having only modest impact on Oregon's ground-level air quality. Those fires, plus fires in Eastern Oregon, are causing "moderate" air quality in much of the eastern part of the state, while air quality in the western part of the state remains "good." Moderate air quality is one step down from good.
The Staley Complex Fire consists of 28 separate fires about 25 miles southeast of Oakridge, most of them under an acre in size.
The Springfield-based Willamette National Forest has 275 personnel and a range of equipment, including four helicopters, battling the fires.
The weather is taking a favorable turn for firefighting, said Scott Weishaar, incident meteorologist, and as a result the U.S. Forest Service expects to ramp up its containment efforts later this week.
The weather system that brought so much lightning to the Southern Cascades last week is moving on, he said.
"A more stable flow (from the west) aloft will?...??continue through the rest of the week," Weishaar said. "This will eliminate the thunderstorm threat and bring daytime temperatures closer to normal."
Crews are preparing areas around the Staley fires to conduct burnout operations, possibly later this week.
Burnout operations burn perimeter areas around a fire, isolating the fire and depriving it of fuel for expansion.
Dead and downed trees in the fire areas are continuing to smolder, with occasional rolling debris spreading the fire's edge, the agency said.
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