The emergency proclamation comes ahead of what the U.S. National Weather Service described as a "particularly dangerous situation" Red Flag Warning, with "extreme" wildfire conditions forecast across eastern Washington.

The order prohibits most outdoor and agricultural burning, including yard debris burning, trash disposal, land clearing, weed abatement, bonfires and campfires not contained within designated fire rings or fire pits.

"Our record-setting drought and high winds are creating dangerous conditions across the state," Ferguson said in a statement. "I am declaring an emergency to help prevent loss of life and property damage."

According to the Washington State Department of Natural Resources (DNR), more than 1,000 wildfires have burned approximately 425,000 acres this year, the largest area scorched since 2021.

More than 200,000 acres are currently burning across 12 major wildfires, as the state endures its fourth consecutive statewide drought.

Commissioner of Public Lands Dave Upthegrove warned that firefighting resources were already under significant strain.

"This year has already been one of our busiest wildfire years on record, and we just started August," Upthegrove said, urging residents to avoid activities that could ignite new fires.

The emergency declaration allows Washington to request additional firefighting resources through the Emergency Management Assistance Compact, a nationwide mutual aid system.

Ferguson had already activated 110 members of the Washington National Guard on July 31 to support firefighting efforts, supplementing 27 helicopter crew members mobilised earlier in the month. The latest proclamation authorises further National Guard deployments if required.

The Washington State Fire Marshal's Office said 13 firefighting task forces and three strike teams have been deployed to battle major fires, including the Sinlahekin Fire in Okanogan County, the Bradeen Hill Fire in Stevens County, the Kaiser Canyon Fire in Okanogan County and the Little Giant Fire in Chelan County.

State fire officials urged residents to avoid any activity capable of igniting dry vegetation, including outdoor burning and the use of equipment that could generate sparks.

They also advised motorists to inspect vehicles for dragging chains or mechanical faults that could start roadside fires and reminded smokers to dispose of cigarette butts safely.

The statewide burn ban does not apply to gas- or liquid-fuelled stoves and grills used on non-flammable surfaces or to campfires contained within approved fire rings in designated parks and campgrounds, according to the governor's office.