Updated

Firefighters made some headway against an enormous wildfire that has chased hundreds of residents from their homes, but officials warned it is far from being contained.

The fire, in south-central Montana, has burned 26 homes, blacked more than 280 square miles and is classified as the nation's No. 1 firefighting priority.

"We're still working on this thing on all fronts," said Dixie Dees, a fire information officer.

Crews were able to build additional fire lines around the blaze Monday when the wind didn't pick up as feared. Eight airplanes dumped 14,000 gallons of fire retardant, and a fleet of about seven helicopters dumped 190,000 gallons of water, said Allison Jackson, another fire information officer.

The fire was sparked by lightning on Aug. 22. It was only about 20 percent contained two weeks later, authorities said.

About 265 homes were evacuated in just a few hours Sunday night on the western flank of the fast-moving blaze, said Kelly O'Connell, Sweetgrass County disaster and emergency services coordinator.

Fire officials feared that wind and higher temperatures this week would create extreme fire conditions.

In Washington state, firefighters continued to battle fires that have burned more than 270,000 acres, or nearly 422 square miles.

"Red flag" warnings for low humidity and gusty wind were in effect in north-central Washington on Tuesday for a group of wildfires that had blackened more than 32,000 acres, or about 50 square miles, in a wilderness area north and south of the town of Mazama. Part of the fire had crossed the border into Canada.