By Steve Gorman

(Reuters) - Crews battling a deadly wildfire burning well into its second week near California's Big Sur coast have carved buffer lines around a quarter of its perimeter, steering flames more deeply into the forest and away from populated areas, officials said on Wednesday.

The gradual but steady progress being made against the so-called Soberanes blaze comes as wildfire season in the western United States was reaching its traditional peak, intensified by prolonged drought and extreme summer heat across the region.

The 13-day-old conflagration near Big Sur is one of nearly 30 major wildfires reported to have scorched roughly 700 square miles (1,813 sq km) in 12 states, mostly in the West, according to the National Interagency Fire Center in Boise, Idaho.


"It's bad now and it's going to get worse," AccuWeather long-range forecaster Paul Pastelok said.

Authorities said on Tuesday they had traced the origins of the Soberanes blaze to an illegal campfire left unattended in a state park about a mile from the famously scenic coastal drive known as Highway 1, south of Carmel-by-the-Sea.

Since erupting on July 22, the fire has blackened nearly 46,000 acres (18,600 hectares), destroyed at least 57 homes and claimed the life of a bulldozer operator who died when his tractor rolled over as he helped property owners battle the blaze.

He became the sixth wildfire fatality in California this year.

Efforts to quell the Soberanes fire have been complicated by steep, rugged terrain and persistently hot, dry weather, said Erik Scott, a spokesman for the fire command.

As of Wednesday morning, a firefighting force that has grown to more than 5,500 had managed to hack through enough unburned vegetation to carve containment lines around 25 percent of the fire's perimeter, up from 18 percent a day earlier.

With the fire now largely hemmed in on its northern flank, closest to communities that were threatened, the blaze is moving primarily in a southeasterly direction deeper into the Los Padres National Forest, Scott said.

Some evacuation orders have been lifted, but fire officials said about 300 residents remained displaced and about 2,000 structures were listed as threatened. Several popular California state parks and campgrounds also were closed.

Another fire, burning north of the San Francisco Bay Area along the Yolo-Napa county line, has scorched 4,000 acres of grass and oak woodlands since it erupted on Tuesday, prompting evacuations of a campground and residential community. Dubbed the Cold fire, that blaze was listed as just 5 percent contained.

(Reporting by Brendan O'Brien in Milwaukee; Editing by Raissa Kasolowsky and James Dalgleish)