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 big picture: The Hughes Fire ignited north of Santa Clarita, just before 11am Wednesday local time and grew across 5,000 acres in LA and Ventura Counties in just over two hours — making it the biggest and fastest-spreading wildfire since the still-burning Eaton and Palisades Fires erupted on Jan. 7.

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.