A wildfire in the hills near the U.S.-Mexico border exploded early Friday morning over thousands of acres, prompting evacuation orders throughout the Otay Wilderness Area and triggering school closures as well as likely power shutoffs for tens of thousands of people.

Border 2 Fire initially started 2:31 p.m. Jan. 23 in San Diego County. After being active for 20 hours, it has burned 5,389.4 acres, an increase of 1,139 acres since the last update. A fire crew of 692 effectively contained 10% of the fire by Friday noon. The blaze's cause remains under investigation.

The fire that broke out near the U.S.-Mexico border was 10% contained as of Friday morning. It was one of several wildfires that started Thursday.

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.