By Curtis Skinner
SAN FRANCISCO (Reuters) - Firefighters kept battling blazes across drought-parched California on Thursday, and thousands of them made solid progress against a wildfire that has forced 150 people to evacuate homes outside of San Francisco.
Firefighters had drawn containment lines around about 33 percent of the so-called Jerusalem Fire, which grew overnight to cover 23,500 acres (9,510 hectares) by Thursday morning, according to the California Department of Forestry and Fire Protection (Cal Fire).
The inferno, which is charring ranch land north of Napa Valley wine country some 100 miles (160 km) outside of San Francisco, has displaced about 150 people and threatens at least 50 more houses and ranches, Cal fire said.
Cal Fire spokesman Steve Swindle said most of the fire's growth has been to the north, away from communities near Lake Berryessa. He said fire breaks in the area, installed by crews over the last several years, have served as a cushion against the blaze.
"We have worked furiously to put containment lines around there to keep those communities safe," Swindle said.
Firefighters have also been able to contain 95 percent of a behemoth 69,438-acre fire burning just to the north. The so-called Rocky Fire, California's fiercest wildfire so far this season, destroyed 43 homes along with dozens of outbuildings and caused hundreds to flee their homes.
Swindle said cooler temperatures should help firefighting efforts in the region through Thursday, though winds could stoke fire activity.
Experts have predicted an unusually active and destructive wildfire season in California as the state grapples with a fourth year of crippling drought. The California fires were among dozens of blazes burning elsewhere across the U.S. West.
The Wolverine Fire in the northern Cascade mountains of Washington state has grown to cover 37,010 acres (14,977 hectares) and could grow further on Thursday amid dry and hot conditions, according to the InciWeb fire information center.
That blaze forced about 360 people to be evacuated from a camping area in the year round Lutheran retreat of Holden Village, fire officials said.
(Reporting by Curtis Skinner; Editing by Daniel Wallis and David Gregorio)