A blaze in a rugged area south of San Jose threatened hundreds of structures and destroyed at least one home as it burned aggressively, after charring more than 3 square miles of dry brush and timber.

A heat wave in parts of drought-stricken California worsened the wildfire that began Monday and forced hundreds of people from their homes in remote communities along the Santa Cruz Mountains.

It was 10 percent contained Tuesday night, the California Department of Forestry and Fire Protection.

One remote area where the fire burned is 30 minutes up a winding dirt road. Another is dotted with large-scale marijuana growing operations. A main route along the ridgetop is not accessible, even to firefighters, because of downed utility lines.

Flames lit up the mountainside above a roller coaster at Santa Cruz Beach Boardwalk, and a residence was reduced to rubble, though its hot tub still stood. The fire consumed a large home sitting on a hilltop plot and poured out thick, black smoke, while another house sat unscathed below.

The blaze broke out Monday during a statewide heat wave that brought witheringly low humidity and temperatures in the upper 90s.

The heat baked even coastal cities that normally benefit from the Pacific Ocean's cooling effect. But the high temperatures were expected to start easing late Tuesday.

"This fire is a good reminder that even though we are approaching October, this time of year is historically when we experience the largest and most damaging wildfires," Cal Fire spokesman Daniel Berlant said.

It threatened 300 buildings, though it's not clear if they were homes or smaller structures. The fire, which was partially under control, also burned close to television and radio towers. No injuries were reported.

Anthony Lopez returned to his home, which is still under evacuation orders, Tuesday. He was overjoyed to find his dozens of marijuana plants standing and his 1972 Buick Skylark uncharred.

Doreenann Bellamy packed her dog, photo albums and firearms into her pickup truck as she and her husband left their home.

"Everyone on the mountain has guns, and you've got to grab your guns first," she told The Mercury News in San Jose (http://bayareane.ws/2cH4hpE ).

Danielle Mays anxiously waited for a neighbor to bring her Boston terrier, Layla, and her cat, Callie.

"That's it; that's what matters," Mays told the newspaper Monday. "I have fire insurance for the rest."

To the north, embers from eucalyptus trees engulfed in flames spread to 13 homes, destroying four houses in a Petaluma, California neighborhood of modest homes bordered by a major highway, authorities said.

Petaluma fire Battalion Chief Jeff Holden said damage in the other homes ranged from a scorched fence to burned backyard decks, sheds and windows.

One woman was injured and received burn blisters on the bottom of one foot.

The fire started in grass near an off ramp of Highway 101 and was blown by the wind into parched eucalyptus trees, Holden told the Press Democrat.

Authorities evacuated about 20 homes and shut down most of the freeway's northbound lanes for nearly two hours.

Dozens of firefighters from nearby cities joined Petaluma fire crews to fight the blazes. The last crew clearing the scene five hours after the fires started, Holden said.