Nursing home residents were evacuated because of smoke from a nearby wildfire, one of several started by lightning from thunderstorms that rolled across the Northwest.

Firefighters also faced new fires in parts of Idaho and Oregon.

More than 75 firefighters were assigned Tuesday to the blaze outside Dayton, which had raced across 2,500 acres — nearly 4 square miles — of trees, brush and wheat fields since being ignited late Monday, said Ted Paterson, information officer for the Columbia County Emergency Operations Center.

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South of Dayton, in eastern Washington, about 80 residents along the Touchet River were urged to evacuate, and 35 residents of a nursing home were evacuated because of concern about the smoke, Paterson said.

No structures had burned, and no injuries were reported.

The Northwest Interagency Coordination Center in Portland, Ore., positioned fire crews throughout Washington and Oregon as a precaution because of dry, windy weather moving in behind Monday's storms, said Vladimir Steblina, spokesman for the Okanogan and Wenatchee national forests.

"Everybody is kind of waiting on pins and needles to see what happens," he said.

The largest group of fires in Washington had blackened more than 180 square miles of forest between the north-central towns of Winthrop and Conconully since being started by lightning in July. Firefighters said it was 40 percent contained Tuesday.

Residents of Winthrop and Conconully had been told to be prepared for possible evacuation.

Among the new fires in central and eastern Oregon, one was threatening the small town of Fields. Authorities said it was burning aggressively, but residents remained in their homes Tuesday morning.

Firefighting resources in Oregon are stretched thin.

"For us, that means we won't be receiving much outside help and will have to do the best we can with what we have," said firefighters' spokesman Jonathan Manski. "In some cases, that may mean leaving a fire unstaffed for a day or so."

Lightning started a dozen new fires late Monday in Idaho's Boise National Forest, including a 300-acre blaze that prompted evacuation of a nearby public hot springs and campground, authorities reported Tuesday. Meanwhile, a fire eight miles west of Silver City that was started by lightning Monday grew to 10,000 acres.

Elsewhere, crews in West Texas were still trying to contain a wildfire that had blackened about 7,500 acres since starting Friday. It was about 50 percent contained in rugged terrain some 85 miles west of Fort Worth.

The fire was believed to have been started by sparks from a truck riding on a wheel rim after a tire blowout.

"Everything is just so crispy dry right now, you have a spark and there you go," said Texas Forest Service spokeswoman Laura Polant.

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