Residents of 860 homes have been told they should leave immediately, fire spokesman Rick Acosta said Wednesday night. A Chelan County emergency management spokeswoman said earlier that another 800 homes were less seriously threatened.
There was zero containment on the Chiwaukum Creek fire burning about 10 miles north of Leavenworth, Acosta said. Smoke from the blaze hung over that nearby Bavarian-themed village and a light dusting of ash fell.
The blaze has prompted the closure of a 35-mile stretch of U.S. Highway 2, stretching to Stevens Pass in the Cascade Mountains.
A spokesman earlier estimated the fire's size at nearly 2 square miles but Acosta said it was so smoky and the fire has moved so quickly that officials just didn't know how big it was.
Worsening wildfire activity has prompted the governor's offices in both Washington and Oregon to declare a state of emergency, a move that enables state officials to call up the National Guard. In Washington, that declaration covers 20 eastern Washington counties.
Wildfires were also burning in Nevada, Idaho, Utah, Oregon and California.
The Chiwaukum Creek fire, first detected Tuesday, was believed caused by lightning. It sent a smoke plume 25,000 feet into the air.
Continuing hot weather and winds gusting to 25 mph were expected Thursday.
Fire spokesman Mick Mueller said there was no confirmed loss of any homes by Wednesday evening.
In southern Oregon, a Klamath County wildfire turned out to be more destructive than authorities initially believed.
After the fire burned in the rural Moccasin Hill subdivision near Sprague River earlier this week, officials reported that six houses were destroyed, along with 14 outbuildings. But fire managers toured the burn area Tuesday and spokeswoman Ashley Lertora said they found 17 residences and 16 outbuildings destroyed.
Oregon fire officials said Wednesday that the Bailey Butte fire - part of the Waterman Complex - had burned more than 3 square miles west of Mitchell and was moving south into the Ochoco National Forest. Two other fires near Service Creek and Kimberly brought the Waterman Complex to more than 6 square miles, or 4,000 acres. The fires are in timber, grass and brush.
In north-central Oregon about 15 miles north of the town of Warm Springs, the lightning-caused Shaniko Butte fire spread quickly in dry, grassy fuels. Pushed by wind, it had burned across 20,000 acres, or 31 square miles, by late Wednesday. It started Sunday.
Fire officials said a handful of new wildfires, some started by lightning, were growing in central Washington.
The state's largest wildfire, the Mills Canyon blaze near the town of Entiat, was 40 percent contained and holding steady at about 35 square miles.
State fire assistance was ordered for the Carlton Complex of fires burning in north-central Washington's Methow Valley, where residents of about a dozen homes have been told to leave. Spokesman Jacob McCann said Wednesday evening that complex has burned across 7 square miles with zero containment.
The Washington National Guard sent two helicopters and 14 people to help battle the blaze.
In Utah, a wildfire encroaching on homes in the Tooele County town of Stockton had burned about 400 to 500 acres. Utah Division of Forestry, Fire and State Lands spokesman Jason Curry said the fire burned part of a water tower but it's believed no homes have been destroyed.
In central Idaho, the lightning-caused Preacher Fire has scorched nearly 53 square miles in two days, burning quickly through grass and brush. But fire managers said Wednesday they had made good progress.
In Nevada, fire crews have the upper hand on a lightning-sparked wildfire near Reno. But the forecast calls for thunderstorms that could bring new fire threats.
About 120 firefighters remained on the lines Wednesday evening at the blaze that has burned just over a square mile of brush and grass on U.S. Forest Service land near U.S. 395 northwest of Reno. No structures were threatened.
The fire was estimated to be 20 percent contained Wednesday evening.
Evacuation orders have been called off for several rural homes in Northern California as firefighters took advantage of cool, moist conditions.
Some residents near the fire in Shasta County have been advised they may need to evacuate again, and the blaze that has burned more than 10,000 acres - or nearly 17 square miles - still poses a threat to nearly 70 homes, state fire officials said in a statement Wednesday night.
The fire was 40 percent contained, up from 20 percent on Tuesday.
Marijuana-growing activity led to the fire breaking out on Friday and subsequently destroying eight homes, authorities said.