A wind-driven fire continued to scorch thousands of acres 60 miles east of San Francisco, prompting residents to flee their homes and the closure of two major freeways near the central California city of Tracy.
The California Department of Forestry and Fire Protection said the fire erupted Saturday afternoon in the grassy hills managed by the Lawrence Livermore National Laboratory, one of the country's key centers for nuclear weapons science and technology.
Authorities said the research center was not under immediate threat from the blaze, dubbed the Corral Fire, which had devoured some 20 square miles by Sunday afternoon and was only 15% contained.
Nevertheless, authorities ordered some residents to leave the area and set up evacuation centers.
The wildfire presented no threats to any laboratory facilities or operations and the fire had moved away from the site, Lawrence Livermore spokesperson Paul Rhien said in a statement to The Associated Press early Sunday.
"We have been working in close partnership with Cal Fire, Alameda County Fire Dept, and other emergency services partners throughout the evening," Rhien said. "As a precaution, we have activated our emergency operations center to monitor the situation through the weekend."
It was not immediately known how many structures had been destroyed by the fire. Photos showed a wall of flames moving over the parched landscape as dark smoke billowed into the sky.
California firefighters aided by aircraft battled a wind-driven wildfire that continued not only burning but spreading early Sunday in an area straddling the San Francisco Bay Area and central California, authorities said.
"Strong winds and dry grass have made it difficult for firefighters to contain," Cal Fire said in a Facebook post Sunday morning.
Interstate 580, which connects the San Francisco Bay Area to San Joaquin County in central California, was closed from the Alameda County line to the Stanislaus County Line. SR 132 was also closed from I-580 to SR 33 due to the wildfire, the California Department of Transportation said in a statement.
The San Joaquin County Office of Emergency Services issued an evacuation order for areas west of the California Aqueduct, south of Corral Hollow Creek, west to Alameda County and south to Stanislaus County. A temporary evacuation point was established at Larch Clover Community Center in Tracy.
Sunday's high temperature for Tracy was expected to reach 85 degrees Fahrenheit, with no rain in the forecast, but hotter conditions are on their way.
The National Weather Service said "dangerously hot conditions" with highs of 103 F to 108 F were expected later in the week for San Joaquin Valley, an area that encompasses the city of Tracy. Wind gusts of up to 45 mph lashed the region Saturday night, according to meteorologist Idamis Shoemaker of the NWS Sacramento.