The blazes - named Laguna, Sepulveda, Gibbel, Gilman and Border 2 - flared up on Thursday in Los Angeles, San Diego, Ventura and Riverside.

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.

LA County Sheriff says about 31,000 people were under mandatory evacuation orders while another 23,000 were under evacuation warnings.