An explosive new wildfire erupted north of Los Angeles on Wednesday, forcing tens of thousands of people to evacuate their homes and setting nerves jangling in an area still reeling from two deadly blazes. Ferocious flames devoured hillsides near Castaic Lake, spreading rapidly to cover more than 9,400 acres in just a few hours.

More than 50,000 people were under evacuation orders or warnings Wednesday as a huge and fast-moving wildfire swept through rugged mountains north of Los Angeles, as parched Southern California endured another round of dangerous winds and two major previous blazes continued to smolder.