Yosemite wildfire only 7 pct. contained; Rim fire chars 225 sq. miles YOSEMITE NATIONAL PARK, Calif., Aug. 26 (UPI) -- A wildfire the size of Chicago burning into Yosemite National Park was 7 percent contained Monday as thousands of firefighters tried to get it under control. The massive, fierce Rim fire in California's central Sierra Nevada region -- one of the largest fires in California history -- devoured more than 144,000 acres, or 225 square miles, as of late Sunday and was only one ridge line away from foothill communities around Tuolumne City, about 60 miles northeast of Modesto. Firefighters said the Rim fire was so hot it could propel sparks more than a mile and a half -- possibly allowing the fire to jump lines and start new hot spots. About 3,000 firefighters from across the state and as far away as Florida were prepared to defend homes and other buildings from the fire, which started Aug. 17 in the Stanislaus National Forest east of Groveland. The state Department of Forestry and Fire Protection deployed nine helicopters. Crews were keeping a watchful eye on changing winds, particularly in light of what happened shortly after the fire was first observed, the Los Angeles Times reported. U.S. Forest Service spokesman Lee Bentley said "things looked good" after an air team dropped water on the fire -- but winds picked up the next day. "The fire came boiling out, just cooking," Bentley said. It was so hot it created its own weather. It was like dropping a boulder in a pond; fire spread out in every direction. A key priority was preventing the fire from spreading further in Yosemite National Park, internationally recognized for its spectacular granite cliffs, waterfalls, clear streams, giant sequoia groves and biological diversity. The fire has burned some Yosemite acreage, but the most-visited area of the park, the Yosemite Valley, was not immediately threatened, officials said. California, Gov. Jerry Brown declared a state of emergency for San Francisco and San Francisco County Friday after the fire -- whose flames are leaping across treetops, creating a "crown fire" -- damaged the Bay Area power infrastructure and threatened the Hetch Hetchy reservoir, San Francisco's main water source, serving 2.6 million customers, or 85 percent of the city's water supply. The fire's fast growth began to slow, officials said late Sunday. "We are making good progress," state forestry spokesman Daniel Berlant told the San Francisco Chronicle. It hasn't grown at the rate it did earlier. Officials said the fire tripled in size from Wednesday to Thursday and then doubled again from Thursday to Friday. Evacuation advisories were lifted for the communities of Pine Mountain Lake, a private, gated community in Tuolumne County, and Buck Meadows, population 31, just south of the Tuolumne County line. State and local officials prepared for the possibility of new evacuations elsewhere and disruptions to public utilities as the fire burned north and east in extremely dry conditions and hot weather. The fire destroyed 23 structures so far. No one was reported killed.