Eastern Washington fires have burned 600 structures and forced the evacuation of 5,000 homes

About 5,000 homes have been evacuated and about 600 homes, businesses and other buildings have been destroyed by wildfires that remained uncontained Sunday in eastern Washington state, authorities said.

The fires burned more than 8.2 square miles (about 21 square kilometers) around Spokane, the second largest city in Washington, and were among dozens across the western U.S. — stretching the ability of federal, state and local agencies to fight them. No deaths have yet been reported from the fires in the Spokane area.

Meanwhile, crews using bulldozers and helicopters continued for the 10th day to fight a fire that has burned nearly 525 square miles (about 1,360 square kilometers) of grassland in western Idaho and eastern Oregon. The area is home to cattle ranches, and authorities said the fire is threatening more than 600 homes and 800 other structures.

The weather in the area was expected to remain sunny — and dry — well into the week, with temperatures rising to more than 90 degrees Fahrenheit (32 degrees Celsius) on Wednesday. Officials say the fire was caused by lightning.

The National Weather Service issued warnings about the air quality in eastern Washington, eastern Oregon, western and central Idaho and western Montana. It issued red flag fire warnings for parts of Utah and Montana and western Nebraska, and extreme heat warnings for the southern parts of Arizona, California and Nevada and northern Montana.

While the high temperature Sunday in Spokane was forecast to remain below 80 F (27 C), wind gusts from 35 mph (56 kph) to 45 mph (72 kph) were expected later in the day, said Benjamin Cossel, public information officer for the federal response team from California called in Saturday night to deal with the Spokane-area fires.

“We have weather working against us, and we have terrain working against us,” Cossel said.

There were three fires in the Spokane area, the Old Trails Fire, the Fairview Fire and the Meadowview Fire, and the state issued air quality warnings. Washington Gov. Bob Ferguson declared a state of emergency Saturday, and the National Weather Service issued a “particularly dangerous situation” red flag alert for eastern Washington.

Cossel said that as it gets warmer during the day, cool air that’s now closer to the ground and keeping winds at bay will rise, allowing those winds to move through the area. The Spokane River cuts through the city of about 229,000 people, and there are steep canyons on both sides that channel the wind.

“They push the fire through the canyons, up, up the slopes, and then outside the slopes and around,” he said. “It’s very, very hilly, very, very steep slopes, a lot of canyons that create really turbulent, really challenging sort of wind scenarios.”

Authorities in Spokane set up a shelter at the city’s main convention center.

“The whole northwest is heavily impacted right now,” said Keila Vizcarra, the spokesperson for the federal team from California handling what’s been named the Big Grass Fire in western Idaho and eastern Oregon.