A fierce 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 60,000 acres and destroyed two dozen houses 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.
The flames raced through 20,000 acres in one five-hour stretch on Saturday night, a growth rate that officials from the California Department of Forestry and Fire Prevention (Cal Fire), described as "unprecedented."
They said the biggest single factor has been the extremely desiccated condition of the thick chaparral and scrub oak fueling the fire, a natural tinder box created by four years of drought and stoked by gusty winds.
What sparked the Rocky Fire remained under investigation, but Cal Fire Chief Ken Pimlott said on Sunday that the blaze was one of more than 20 large conflagrations across the state following thousands of lightning strikes in recent days.
He said more than 9,000 firefighters, many of them reinforcements from out of state, were on the lines 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.
Despite growth in the size of the blaze overnight into Monday morning, Cal Fire reported ground crews had managed to carve buffer lines around 12 percent of the fire zone, more than double the containment during the two previous days.
"Yes, we are gaining some ground," Cal Fire spokesman Jason Shanley said.
Some 6,300 structures - a combination of homes, barns, sheds and other buildings - remained under threat after the loss of 24 dwellings and 26 outbuildings last week.
More than 13,000 people, about 1,000 more than on Sunday, have received mandatory evacuation orders or advisories, Cal Fire said.
No serious injuries have been reported. But a Forest Service firefighter from South Dakota died on Thursday in a separate, smaller fire roaring through Modoc National Forest near California's border with Oregon.