Updated at: 09/01/2013 11:35 PM
(AP) YOSEMITE NATIONAL PARK, Calif. - The wildfire burning in and around Yosemite National Park has become the fourth-largest conflagration in modern California history, fire officials said Sunday as clouds and higher humidity helped crews further contain the biggest blaze in the United States this year.
The 2-week-old Rim Fire moved up a spot on the state’s list of large wildfires dating back to 1932 when it grew to 351 square miles _ an area larger than the cities of San Francisco, Oakland and San Jose combined, California Department of Forestry and Fire Protection spokesman Daniel Berlant said.
Although the fire still is growing, it was 45 percent contained as of Sunday.
Moister air slowed flames from advancing through brush and trees, giving firefighters room to set backfires, dig containment lines and to strengthen lines around threatened communities, fire spokesman Trevor Augustino.
He said it also helped that more than 4600 firefighters were brought in to battle the flames.
"We’re going in the right direction," Augustino said.
Full containment is not expected until Sept. 20.
The blaze started Aug. 17 in the Stanislaus National Forest and two-thirds of the land burned since then is located there as well. In Yosemite, 94 square miles have burned. The cause remains under investigation.
Meanwhile, the dense smoke that obscured Yosemite’s majestic views for the first time on Saturday and prompted air quality warnings was starting to ease, park spokeswoman Kari Cobb said.
Although park officials advised visitors to avoid heavy exertion, Cobb said she has seen people outside running "and enjoying Yosemite, despite the smoke."
"The park was actually busier than I thought it would be," she said.
A 427-square-mile fire in San Diego County that killed 14 people and destroyed more than 2,800 structures a decade ago tops the list of California’s largest wildfires.
The Rim Fire has claimed 111 structures, 11 of them homes.
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