More than 7,800 firefighters battled wildfires roaring across the state Saturday, as bone-dry terrain and heat created prime conditions for the blazes to spread rapidly. The worst of the fires, the so-called King Fire that burned just east of Placerville in El Dorado County, spread an additional 6 square miles overnight and was just 10 percent contained as of Saturday afternoon, according to the California Department of Forestry and Fire.