Yosemite fire near Wawona grows to 900 acres

The South Fork Fire, burning along the Merced River’s south fork in Yosemite National Park, grew overnight Sunday to 900 acres. The South Fork Fire, burning along the Merced River’s south fork in Yosemite National Park, grew overnight Sunday to 900 acres. Image 1 of / 58 Caption Close Yosemite fire near Wawona grows to 900 acres 1 / 58 Back to Gallery

Firefighters worked Monday to halt the spread of a wildfire at the southern edge of Yosemite National Park that was burning just a little more than a mile from the small community of Wawona.

The South Fork Fire, which ignited Sunday afternoon in wilderness east of the town, grew overnight from 400 to 900 acres, but mostly burned to the north and away from people and homes, according to federal fire officials.

Fire officials told Wawona residents to prepare for evacuations, but none were ordered. Park rangers shut down the area’s Chilnualna Falls Trail and visitors on the southern end of Yosemite were warned about heavy smoke.

The cause of the blaze was under investigation.

Several other fires in the park were blamed on lightning strikes over the weekend, officials said. The largest was the Empire Fire, which had scorched about 1,200 acres in a remote area north of the South Fork Fire as of Monday morning.

Ten lightning-caused wildfires have started since July 31, according to the park service.

Kurtis Alexander is a San Francisco Chronicle staff writer. Email: kalexander@sfchronicle.com Twitter: @kurtisalexander