Firefighters Friday were trying to make progress after the Canyon fire exploded to nearly 5,000 acres, forcing residents in northern Los Angeles and Ventura counties to evacuate.

Fire officials say the blaze is threatening power lines as well as the communities of Hasley Canyon and Hathaway Ranch.

Temperatures in the area are near 100 degrees and humidity as low as 15 percent. The southern part of California has seen very little rain, drying out vegetation and making it "ripe to burn," the National Weather Service (NWS) for Los Angeles warned.