A fast-moving wildfire erupted several miles north of the U.S.-Mexico border in the San Diego area, blackening thousands of open acres as ground and airborne crews worked Friday to quell the flames amid arid and blustery Santa Ana conditions.

Authorities issued evacuation orders and warnings to nearby areas early Friday morning as a wildfire in the Otay Wilderness Area exploded to 4,250 acres in rugged terrain overnight. Crews were able to get 10% of it contained.

Firefighters have slowed the spread of a huge wildfire churning through rugged mountains north of Los Angeles where dangerous winds gained strength again.

The fire threat remains critical in Southern California, where thousands of residents were under evacuation orders Wednesday as fire crews battled the out-of-control Hughes Fire near Castaic, a suburb in the foothills and mountains of northern Los Angeles County.