A wind-whipped fire that destroyed 13 homes and burned pleasure boats on a lake forced residents of this affluent Gold Rush country town Monday to evacuate a second time.

The fire was fanned by 30 mph gusts and fueled by drought-dry bush, wood roofs and propane tanks which exploded like small bombs, said state Department of Forestry spokesman Charlie Jakobs. Flames destroyed 20 to 30 structures, including 13 homes."The fire laid down a little during the night but picked up this morning," he said of the blaze in the Sierra Nevada foothills.

More than 1,220 federal, state and local firefighters were on the fire lines Monday in one of California's most scenic and historic areas, Jakobs said.

Residents of this mountain town of 4,500 people 45 miles northeast of Sacramento and the tiny town of Rough and Ready were evacuated Sunday, and Highway 49 was closed.

They were allowed to begin returning home this morning, but were ordered evacuated again later.

Nevada County officials declared a state of emergency, initiating a process to make the county eligible for more state and federal assistance.

Most schools in the area were closed. Thick smoke made it unsafe to operate school buses and the Red Cross needed some schools for evacuation centers.

A firefighter suffered minor hand burns when flames engulfed his bulldozer, forcing him to wrap himself in an asbestos blanket and take refuge under his vehicle.

Meanwhile, a new fire broke out less than a half mile from the main blaze and burned 700 acres by early today, said Erin Connelly, spokeswoman for the U.S. Forest Service. She estimated the overall acreage at 12,000.

The main fire, which began Sunday morning along Highway 49 about 30 miles northwest of Nevada City, was apparently caused by an illegal burn of debris, said U.S. Forest Service spokeswoman Ann Dow.

Before their evacuation, weary, soot-smeared homeowners used chain saws and hoses in an effort to keep the fire from spreading.

"We're ready to leave if we have to, but until then we'll stay and help out," resident Gary Hultquist, 41, said Sunday night as he helped hose down a neighbor's burning house. "Everything you got could go up in flames."

Some made sure families and animals were safe, then returned to battle the blaze after nightfall as hot spots glowed in the hills.

"Nobody expected it to come in fast like this," Mike Fitzgerald, 38, said as he cut down a large, smoldering tree in his yard.

Firefighter Bernie Paul, 31, suffered hand burns after fire swept over his bulldozer.

"I thought I was done for more than once," Paul said. "It feels good to be alive."

The fire burned southwest, straddling Highway 29 and crossing the South Fork of the Yuba River.