Wildfires force 60,000 to evacuate as hundreds of structures burn in Washington state

Wildfires sweeping through eastern Washington forced about 60,000 people to evacuate in and around Spokane, destroying at least 600 homes, businesses and other structures, authorities said on Sunday.

The fires in and around Spokane, Washington's second-largest city, burned about 8.2 square miles (21 square kilometres) over the weekend and were among dozens of wildfires stretching firefighting resources across the western United States.

Statewide, about 390 square miles (1,000 square kilometres) have burned, with several fires, including those near Spokane, remaining uncontained.

Authorities said there were no immediate reports of injuries or missing people, although they cautioned that the response was still in its early stages. Evacuations included patients from the US Department of Veterans Affairs hospital in Spokane.

Images from the area showed homes and other buildings engulfed in flames, with thick black smoke rising over neighbourhoods and many structures reduced to ruins.

US Senator Maria Cantwell warned that the danger was far from over, with dry conditions expected to persist in the coming days.

"We are not out of danger," she said during a briefing with federal, state and local officials.

Investigators have yet to determine the cause of the Spokane-area fires.

Elsewhere in the West, firefighters continued battling a blaze that has scorched nearly 525 square miles (1,360 square kilometres) of grassland across western Idaho and eastern Oregon. The lightning-caused fire has threatened more than 600 homes and 800 other structures.

In central Utah, a wildfire more than tripled in size over the weekend to about 56 square miles (145 square kilometres), killing more than 100 cattle. Authorities described the blaze as "catastrophic" after strong winds pushed it beyond containment lines and prompted mandatory evacuations in parts of Fillmore.

The National Weather Service issued air quality warnings across parts of the northwestern United States, along with red flag fire warnings for parts of Utah, Montana and western Nebraska. Extreme heat warnings remained in effect for southern Arizona, California and Nevada, as well as northern Montana.

In Spokane, strong winds continued to hamper firefighting efforts. Washington Governor Bob Ferguson declared a state of emergency on Saturday, while the National Weather Service issued a "particularly dangerous situation" red flag warning for eastern Washington.

Officials opened an emergency shelter at Spokane's main convention centre, where about 400 evacuees were staying as of Sunday. Around 10,000 customers remained without electricity, down from a peak of 30,000, after wildfires damaged power infrastructure.

Several large fires also continued burning in remote areas of Washington and eastern Oregon as authorities warned that much of the northwestern United States remains at high risk from wildfires.