BIG BEAR LAKE, Calif. — A wildfire along the Pacific Crest Trail in Southern California surged to 850 acres and prompted closures and calls for optional evacuations.

The U.S. Forest Service says the fire broke out amid blazing heat Monday in the San Bernardino Mountains northeast of Big Bear Lake.

It’s not an immediate threat to any structures, but sections of the Pacific Crest Trail and State Route 18 are shut down.

People in the tiny communities of Holcomb and Baldwin Lake have been told they may want to evacuate, but no orders were issued.

There is no containment early Tuesday. Aircraft are making water-dropping runs over the flames.

The burn area, dotted with mines from the gold rush, is about 200 miles (322 kilometers) east of Los Angeles.