SAN FRANCISCO, Sept 8 (Reuters) - Authorities in northern California went door-to-door on Sunday to order the evacuation of dozens of homes in the path of a small but fast-growing brush fire near Mount Diablo State Park, northeast of San Francisco.
The so-called Morgan fire was first reported on Sunday afternoon and within a few hours had devoured 400 acres (162 hectares) of dense, dry brush and grass southeast of the town of Clayton, according to California Department of Forestry and Fire Protection spokeswoman Julie Hutchinson.
She said residents of 50 to 75 homes threatened by the blaze were ordered to flee,
"The fire was initially very difficult to access," Hutchinson said. "Now it's easier to access, but it's getting in and around the homes."
The state park is about 40 miles (64 km) northeast of San Francisco.
About 175 firefighters backed by aerial assaults from water-dropping helicopters and tanker planes carrying flame retardant had managed to carve containment lines around 10 percent of the blaze.
Personnel from the Contra Costa County Fire Protection District and the Contra Costa County Sheriff's Office were spearheading the firefighting and evacuation efforts.
The Clayton Community Library was converted to a temporary evacuation shelter to accommodate those forced from their homes.
The blaze near Clayton pales in comparison with the monster Rim fire still burning in and around Yosemite National Park roughly 200 miles (322 km) to the east.
That blaze, believed to have been sparked by a hunter's campfire that grew out of control, has blackened more than 253,000 acres, or 395 square miles (102,000 hectares), of timber and dry brush since it erupted on Aug. 17 in the Stanislaus National Forest west of Yosemite.
It ranks as the third-largest California wildfire on record and the biggest of dozens of blazes that have raged across several states in the drought-parched west this year.
The cause of the Morgan fire was under investigation, Hutchinson said. (Reporting by Jonathan Kaminsky; Editing by Steve Gorman and Christopher Wilson)