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

A brush fire started on a sweltering day east of Lake Piru in Ventura County and led to evacuations as this week’s warm temperatures in Southern California reached their peak. The Canyon Fire was estimated at about 50 acres early Thursday afternoon before quickly spreading to more than 4,

The Canyon fire broke out around 2 p.m. near Holser Canyon Road, northeast of Piru. By Thursday night, it was pushing east toward Castaic and Interstate 5.