(Reuters) – More than 1,200 firefighters aided by water-dropping helicopters battled a wildfire raging out of control in Northern California, threatening homes and other structures as thick black smoke drifted across the San Francisco Bay Area.
The so-called County Fire, which broke out on Saturday afternoon in Yolo County west of Sacramento, has already blackened more than 50 square miles of grass, brush and dense scrub oak.
Crews worked through the night to cut control lines around the blaze, which grew by one-third overnight Sunday, and officials ordered evacuations in several Yolo County communities.
The smoke reached San Francisco, 75 miles (120 km) to the south, leaving films of ash on cars and windows.
The blaze, the worst of more than a dozen wildfires burning across the state, was only 3 percent contained as of Monday afternoon and was burning into Napa and Lake Counties as well.
No casualties had been reported.
“Extreme fire behavior is still being observed,” the California Department of Forestry and Fire Protection said.
Wildfires have burned through nearly 2.5 million acres (1 million hectares) in the United States as of June 29, well above the average of about 2 million acres for the same calendar period over the last 10 years, according to the National Interagency Fire Center, a monitoring group.
California and Colorado have been hard hit. The largest wildfire in Colorado, the 416 Fire, has consumed more than 51,000 acres, about 13 miles (21 km) north of Durango in the southwestern part of the state. It is 37 percent contained, according to state data.
In 2017, a near record 10 million acres (4 million hectares) were burned in wildfires, the National Interagency Coordination Center said.
The agency issued a forecast in June for “above-normal significant large fire potential” this month in southern California and the Four Corners region of Colorado, New Mexico, Arizona and Utah, because of a deepening drought and ample fuel for wildfires.
Reporting by Jonathan Allen in New York and Dan Whitcomb in Los Angeles; Editing by Jeffrey Benkoe and Grant McCool