Crews begin to gain ground against northern California wildfire

SAN FRANCISCO (Reuters) - A wildfire that has devoured drought-parched terrain in northern California with remarkable speed raged on for a sixth day on Monday as evacuations expanded and firefighters began to gain some ground against the flames

The blaze, dubbed the Rocky Fire, has scorched some 62,000 acres and destroyed more than 50 structures since erupting last week in the canyons and foothills along the inland flanks of California's North Coast Ranges, quadrupling in size over the weekend.

Evacuation orders, both mandatory and suggested, were in place for more than 13,000 people living in over 5,530 residences, according to the California Department of Forestry and Fire Prevention (Cal Fire).

The blaze raced through 20,000 acres in one five-hour stretch on Saturday night, a rate that Cal Fire officials described as "unprecedented."

The flames, stoked by winds, jumped a state highway on Monday that fire crews had hoped would serve as a containment line, Cal Fire said.

The blaze was 12 percent contained on Monday night, officials said.

What sparked the Rocky Fire remained under investigation, but the blaze was one of more than 20 conflagrations across the state following thousands of lightning strikes in recent days, said Cal Fire Captain Kendal Bortisser in an evening update.

More than 9,000 firefighters, many of them reinforcements from out of state, were dispatched in California. A third of that force was assigned to the Rocky Fire alone, along with 19 water-dropping helicopters and four airplane tankers, Cal Fire said.

The blaze erupted on Wednesday in ranch country near the town of Lower Lake, about 110 miles (177 km) north of San Francisco.

Some 6,300 structures - homes, barns, sheds and other buildings - remained under threat after the loss of 24 dwellings and 26 outbuildings last week.

No serious injuries have been reported. But a Forest Service firefighter from South Dakota died on Thursday in a separate, smaller fire in Modoc National Forest near California's border with Oregon.

(Writing by Steve Gorman from Los Angeles; Additional reporting by Steve Gorman and Victoria Cavaliere; Editing by Cynthia Osterman)