The remote blaze in Stanislaus National Forest west of Yosemite grew to more than 25 square miles and was only 5 percent contained, threatening homes, hotels and camp buildings.
The fire has forced the evacuation of a private gated community of Pine Mountain Lake, as well as that of several organized camps, at least two campgrounds and dozens of other private homes. The blaze has already destroyed two residences and seven outbuildings.
The fire also caused the closure of a 4-mile stretch of State Route 120, one of the gateways into Yosemite on the west side. Park officials said the park remains open to visitors and can be accessed via state Routes 140 and 4.
The fire was among the nation's top firefighting priorities, according to the National Interagency Fire Center in Boise, Idaho.
Fifty-one major uncontained wildfires are burning throughout the West, according to the center, including in California, Alaska, Arizona, Idaho, Montana, Nevada, Oregon, Utah, Washington and Wyoming. More than 19,000 firefighters were fighting the fires.
The center listed three fires in Montana as the nation's number one priority on Wednesday. They include a wildfire burning west of Missoula that has surpassed 13 square miles, destroyed five homes, closed U.S. Highway 12 and led to multiple evacuations. The Lolo Fire Complex, which was zero percent contained, also destroyed an unknown number of outbuildings and vehicles.
At least 19 other notable fires were burning across the state, leading Montana Gov. Steve Bullock to declare a state of emergency, which allows the use of National Guard resources ranging from personnel to helicopters.
In Oregon, a fire in the Columbia Gorge about 10 miles southwest of The Dalles grew to 13 square miles, forcing evacuations and burning a third home. The fire was 15 percent contained. Strong winds continued to fan the blaze, pushing it into the Mount Hood National Forest.
Firefighters in southwestern Oregon braced for a return of lightning storms that started a series of fires last month that continue to burn in rugged timberlands.
In Idaho, progress was reported in the fight against the nearly 169-square-mile Beaver Creek fire, which forced the evacuation of 1,250 homes in the resort area of Ketchum and Sun Valley. That fire was 30 percent contained, authorities said.
In Yellowstone National Park in Wyoming, officials reopened a 7-mile section of road closed briefly by a wildfire. As of Wednesday, the Alum Fire had burned about 12 square miles and was spreading slowly, leading park officials to make preliminary evacuation plans for a community on the shore of Yellowstone Lake.