A wildfire burning southwest of Yosemite closed a main route to the California national park and prompted evacuations near the Mariposa County town of Briceburg.

The blaze, dubbed the Briceburg Fire, started Sunday afternoon near the Briceburg Road Bridge over the Merced River. As of about 8 a.m. Tuesday, it had scorched 800 acres and was only 10 percent contained, Cal Fire said.

Caltrans tweeted that Highway 140 was shut from Colorado Road to Savages Trading Post. Visitors traveling to the park or El Portal were advised to take either Highway 41 or Highway 120.

Mandatory evacuations were ordered for several homes along Highway 140 from the Octagon to Buffalo Gulch Road, according to the Mariposa County Sheriff's Office. Also ordered evacuated were the Briceburg Information Center and the McCabe Flat Campground.

Crews are racing the clock to make headway against the blaze before strong winds that are predicted for Wednesday arrive. PG&E has announced it may proactively turn off power to about 30 counties, including Mariposa, to reduce the fire risk.

The Briceburg Fire is burning not far from where the Ferguson Fire charred nearly 100,000 acres last summer. If it happens to advance toward the burn scar, the lack of vegetation and the old bulldozer lines could serve as a fire break.