Yosemite Wildfire Rages On, Becomes Biggest Blaze Ever In Sierra

YOSEMITE NATIONAL PARK (CBS/AP) — The huge wildfire that's crept into Yosemite National Park is now the biggest wildfire on record in California's Sierra Nevada, officials declared Monday.

Nearly 3,700 firefighters were battling the approximately 234-square-mile blaze and reported modest progress, with the fire just 15 percent contained.

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The fire was raining ash on the Hetch Hetchy reservoir that's the chief source of San Francisco's drinking water. Utility officials were moving water to reservoirs closer to the city.

The fire was still several miles away from the steep granite canyon where the reservoir is nestled, but several spot fires are burning closer. Firefighters were protecting hydroelectric transmission lines and other utility facilities.

Meanwhile, park officials cleared brush and set sprinklers on two groves of giant sequoias that were seven to 10 miles away from the fire's front lines.

While it has closed some backcountry hiking, the fire has not threatened the Yosemite Valley, such sights as the Half Dome and El Capitan rock formations and Bridalveil and Yosemite falls draw throngs of tourists. Most of the park remained open to visitors, park spokesman Scott Gediman said Monday.

The U.S. Forest Service said about 4,500 structures were threatened by the fire. At least 23 structures have been destroyed, though officials had not determined whether they were homes or rural outbuildings.

Firefighters were aided by movement of the blaze into less forested areas and cooler temperatures caused at least in part by the shadow cast by the large plume of smoke from the blaze, said Jerry Snyder, a spokesman for the Stanislaus National Forest.

Inaccessible terrain, strong winds and bone-dry conditions have hampered firefighters' efforts to contain the Rim Fire, which began Aug. 17.

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