LOS ANGELES >> A rapidly growing wildfire straddling the Ventura-Los Angeles county line Thursday afternoon triggered evacuations in and around Piru and Castaic amid a major heat wave that officials warned could foster extreme fire growth and behavior.

The Canyon Fire is burning through steep terrain near the Ventura-Los Angeles county line, prompting evacuations and air quality warnings.

An evacuation order has been issued for all of Lake Piru Recreation Area and east to the Los Angeles County line, south to SR 126, west to Center Street.