A fast-moving wildfire exploded to roughly 10,200 acres near the Los Angeles County community of Castaic Wednesday morning, prompting mandatory evacuation orders and road closures, authorities said.

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.

More than 31,000 people have been ordered to evacuate from the Hughes Fire, and another 23,000 are under evacuation warnings, LA County Sheriff Robert Luna said. There were no reports of homes or other structures burned. Parts of Interstate 5 near the Hughes Fire that had been closed reopened Wednesday evening.