California\'s Rim fire threatens 4500 structures

California\'s ravenous Rim fire devoured 180,000 acres and threatened 4,500 structures as fierce winds whipped the flames close to San Francisco\'s water supply. Fire crews reported progress slowing the massive blaze\'s advance, declaring it 20 percent contained late Monday, up from 7 percent Sunday. But the inferno still consumed more than 45,000 tinder-dry acres since Sunday and crept to within a mile of a reservoir that\'s the source of water for 2.6 million San Francisco Bay Area residents and businesses. Most infrastructure carrying water from the Hetch Hetchy dam and reservoir in Yosemite National Park, about 160 miles east of San Francisco, is fire-resistant and underground. But officials expressed concern ash from the roaring wildfire would foul the water. The San Francisco Public Utilities Commission raced 302 million gallons of water a day from the giant reservoir to other reservoirs in the hope of saving the water from contamination, a utility spokesman said. U.S. Forest Service spokesman Dick Fleishman told the San Francisco Chronicle crews were expanding firefighting efforts near Tuolumne City, about 60 miles northeast of Modesto, where high winds put several communities in danger. An evacuation advisory was in place for parts of Tuolumne City, Twain Harte and Ponderosa Pines, Fleishman said. Firefighters used bulldozers to cut firebreaks to halt the flames\' spread, while planes and helicopters dropped retardant from above. California Gov. Jerry Brown toured the area Monday and met with fire officials, firefighters and first responders. He pledged money and personnel to battle California\'s 13th-largest wildfire in state history. \"We have to spend what it takes,\" Brown said in Tuolumne City days after declaring a state of emergency that will help draw federal resources to the firefighting effort. Federal disaster officials offered Monday to pay up to 75 percent of the firefighting cost, which has topped $20 million. Brown said President Obama called him to express support and offer assistance. The fire ignited in a remote section of the Stanislaus National Forest in Northern California\'s Sierra Nevada range Aug. 17. Its cause is not known. It has destroyed 23 structures, including Berkeley\'s Tuolumne Camp, a summer retreat about 5 miles outside Yosemite.