Crews including water-dropping helicopters on the scene of a brush fire at Marine Corps Air Station Miramar. (Photo courtesy of ALERTCalifornia)

A brush fire erupted Monday at Marine Corps Air Station Miramar on the verge of a new spell of dry and gusty Santa Ana conditions, blackening about a dozen open acres but causing no reported structural damage or injuries.

The slow-moving blaze broke out for unknown reasons shortly before 2:30 p.m. on military property near the intersection of Kearny Villa Road and Miramar Road, according to the San Diego Fire-Rescue Department.

It took about 90 minutes for crews aboard a pair of water-dropping helicopters and numerous fire engines to halt the spread of the flames.

The cause of the blaze was not immediately clear.

The predicted onset of more blustery and arid conditions has prompted the National Weather Service to schedule another “red flag” wildfire warning for the San Diego area’s inland valleys and mountains, effective from 4 p.m. Monday through 6 p.m. Wednesday.

City News Service contributed to this article.