The canyon fire began close to Freeway 91 just after 1pm on Monday and has now spread to 2,000 acres, according to the Orange County Fire Authority.
Aircraft and more than 300 firefighters have been deployed to extinguish the blaze, which is only 5 percent contained, according to the fire service’s latest updates.
Four schools have been closed due to the threat from the flames, with Corona City authorities urging people to leave their homes south of Green River Road to the Trudy Way area.
An evacuation shelter has been opened at the Corona High School gymnasium.
Footage posted to social media shows huge fires burning across the hills above the city of Corona, with flames and plumes of smoke cutting across major roadways in the area.