More than 130,000 acres have been burned by a raging wildfire in Northern California as firefighters braced for strong winds that are moving the fast-moving blaze into Yosemite National Park on Sunday, threatening thousands of rural homes and effecting life in places as far away as San Francisco and Reno, Nevada.
The so-called Rim Fire grew to 134,000 acres by early Sunday morning, up 9,000 acres from the day before, with smoke columns rising more than 30,000 feet in the air, U.S. Fire Service spokesman Dick Fleishman said.
"That's a real watch-out situation for our firefighters when they see that kind of activity, they know that the wind could actually move that fire right back on them," Fleishman said.
Officials estimate containment at just 7 percent.
By Sunday afternoon, flames from the fire had already spread into a corner of Yosemite National Park, far enough from tourists, but only a few miles away from a resevoir that supplies hydro electricity and 85 percent of the water supply to the San Francisco, which is nearly 180 miles away. California Gov. Jerry Brown declared a state of emergency for the city on Saturday.
The fire is believe to be one of the biggest in California's history. It's smoke has already drifted across state lines into Reno, Nevada, prompting the cancellation of several outdoor events.
Winds up to 40 miles per hour were expected to push the fire into the park on Sunday, and firefighters were battling to save the communities of Tuolumne City, Twain Harte and Long Barne near the northern edge of the blaze.
Park employees cleared brush and set sprinklers in an attempt to protect two groves of giant sequoia trees, which are among the oldest and largest living things on earth.
"All of the plants and trees in Yosemite are important, but the giant sequoias are incredibly important both for what they are and as symbols of the National Park System," park spokesman Scott Gediman told The Associated Press.
The U.S. Forest Service told Al Jazeera that protecting the sequoias was a contingency plan, adding the trees were not in imminent danger. The Forest Service does not expect the fire to reach the sequoia grove, which is six to eight miles away.
At least 2,600 firefighters and half a dozen aricraft were battling the blaze, which started on Aug. 17 in the Stanislaus National Forest.
"We are making progress but unfortunately the steep terrain definitely has posed a major challenge," Daniel Berlant, a spokesman for the California Department of Forestry and Fire Protection, said earlier.
The Forest Service also said about 4,500 structures are threatened by the fire. Berlant said 23 structures have been destroyed, though it was not immediately clear if they were homes or rural outbuildings.
Brown warned that the fire had damaged the electrical infrastructure serving the city, and forced the San Francisco Public Utilities Commission to shut down power lines. There have been no reports of blackouts in San Francisco.
Ashley Taylor, a spokesperson for the U.S. Forest Service, said high humidity and firefighting efforts had helped some.
"Firefighters are still working with the same difficult situation, and they're really taking every opportunity they can to take hold of this fire," Taylor said. "They're working very hard to take this down."
The Hetch Hetchy Reservoir provides water to 2.6 million customers in the San Francisco area, about 85 percent of the city’s water needs. Brown said the city's water supply could be affected if ashes from the blaze affect the reservoir. No problems were noted by Saturday morning.
Taylor said there is no plan to close Yosemite National Park, which attracted nearly 4 million visitors last year, due to the fire. However, park officials have closed areas in its northwestern edge throughout the week, including the Hetch Hetchy Reservoir area, Lake Eleanor, Lake Cherry and the Tuolumne Grove of Giant Sequoias.
Park spokeswoman Kari Cobb said that the park had stopped issuing backcountry permits to backpackers and had warned those who already had them to stay out of the area.
"Right now there are no closures, and no visitor services are being affected in the park," Cobb said. "We just have to take one day at a time."
Highway 120, one of four access routes to Yosemite, which is known for its waterfalls, giant sequoia groves and other scenic wonders, was temporarily closed. The highway leads to the west side of the 750,000-acre national park.
The 2013 fire season has already drained U.S. Forest Service fire suppression and emergency funds, causing the agency to redirect $600 million meant for other projects like campground and trail maintenance and thinning of trees to reduce wildfire risks, agency spokesperson Mike Ferris has said.
The service has spent some $967 million to protect lives and properties amid a season that has seen fires in Idaho, Utah, Colorado and California threaten homes and communities that border forest and wild lands where fire is more dangerous and costly to fight, Ferris said.
Al Jazeera and wire services