A fire set by the "Calaveras County Arsonist" has burned $1.5 million worth of timber, destroyed at least four homes and angered residents of the Sierra Nevada, who say arson is something that is just not done in mountainous Gold Rush country.

With the fire danger as high as in the rest of the West - parched dry from the drought and blistering heat - residents were fuming at the arson spree that has made a dangerous situation even worse."I am just very angry," said Lou Maconbre of the summer resort and retirement town of Arnold, which was once in the path of the flames but was out of danger Thursday. "We take care of each other up here. We have a lot of elderly and a lot of people who live out in the boontoolies. This kind of thing does not happen."

Rewards totaling $6,000 have been offered for the conviction of the arsonist or arsonists who authorities believe are cruising the area in a camper, torching the land with incendiary devices made from bundles of matchsticks with lighted cigarettes stuck in them.

At least 16 fires in the past month are blamed on the arsonist.

Wildfires were also raging in Wyoming, near Yellowstone National Park, Colorado's Dinosaur National Monument and Alaska, where more than 60 active fires have consumed 922,000 acres in the state's northern interior.

An army of more than 5,000 firefighters was on the lines in the West, battling not only the flames, but temperatures that were consistently above 100 degrees.

All told, Western wildfires were burning over 975,000 acres - more than 1,500 square miles - an area larger than the state of Rhode Island.

The Calaveras County fire grew by about 2,000 acres Thursday to 12,500 acres and was listed by nightfall as 70 percent contained. The blaze destroyed $500,000 in property, including three houses and a mobile home, and has run up another $500,000 so far in firefighting costs, a California Department of Forestry spokesman said.

Arsonists were also blamed for a half-dozen fires set in San Bernardino County about 60 miles east of Los Angeles, the largest of which burned 200 acres and destroyed two small buildings.

In Colorado, a 3,100-acre fire in Dinosaur National Monument was expected to be contained Friday. In rugged central Idaho, weary fire crews controlled a 2,250-acre blaze that started several days ago and burned through sagebrush and grass.

Many of Alaska's fires were being allowed to burn unchecked. The biggest blaze consumed some 300,000 acres in the Yukon Flats National Wildlife Refuge 60 miles north of Fairbanks.