CASTAIC, Calif. — Firefighters fought to maintain the upper hand on a huge and rapidly moving wildfire that swept through rugged mountains north of Los Angeles and resulted in more than 50,000 people being put under evacuation orders or warnings.

Thousands of firefighters worked to contain new blazes Thursday, including one near the affluent Bel-Air neighborhood, while persistent winds left weary Angelenos on edge following weeks of historic fires.