The last evacuation orders have been lifted for hundreds of residents and firefighters were being sent home Monday after reaching 85 percent containment of a wildfire south of Casper.

The fire had covered more than 11,700 acres, or about 18 square miles, since lightning started it Aug. 14.

Hundreds of homes were evacuated last week on Casper Mountain, in central Wyoming about 5 miles south of Casper. Seven cabins, a barn and two outbuildings were burned, officials said.

Only about 100 firefighters were still working on the fire Monday, down from more than 500 last week.

Click here to visit FOXNews.com's Natural Disaster Center

In north-central Washington state, crews already contending with large fires were bracing for thunderstorms forecast late Monday.

"There's not much in the way of precipitation" expected, said meteorologist Ted Buehner with the National Weather Service in Seattle. "The threat is primarily lightning strikes and local gusty wind associated with thunderstorms."

Washington's largest fire, between the north-central towns of Winthrop and Conconully, was reported to be about 182 square miles on Monday, or more than 116,000 acres, and about 30 percent contained.

The fire posed a potential threat to about 300 houses, 120 commercial structures and hundreds of outbuildings. Residents have been told to be prepared for possible evacuations.

A group of wildfires in West Texas was 40 percent contained Monday after charring about 12 square miles since Friday night, said Laura Polant, a spokeswoman for the Texas Forest Service. Wind had died down Monday morning but was expected to pick up during the day, and humidity was low, officials said.

No injuries or deaths have been reported in the fires near Caddo, Texas, but one hunting cabin was burned. Twelve homes threatened by the fires were saved, Polant said.

So far this year, wildfires have charred 6.8 million acres, or nearly 11,000 square miles, according to the National Interagency Fire Center in Boise, Idaho. By this same date last year, wildfires had covered 6.7 million acres.