A fast-moving brush fire dubbed the Canyon Fire erupted around 1:30 p.m. Thursday near Lake Piru on the Ventura–Los Angeles county line and expanded to roughly 1,050 acres in under three hours. By late evening, unofficial estimates put the burn area closer to 1,500 acres, and the blaze remained 0% contained. Ventura County authorities ordered the evacuation of about 4,200 residents and 1,400 structures and issued warnings covering another 12,500 people as flames pushed east toward Hasley Canyon, Hathaway Ranch and the outskirts of Santa Clarita. The fire is also threatening 60-kilovolt power lines and continues to advance toward the community of Val Verde after crossing into Los Angeles County. More than 250 firefighters, backed by helicopters and fixed-wing airtankers, are battling the blaze in triple-digit heat, low humidity and steep terrain that are driving rapid fire behavior. LA County Supervisor Kathryn Barger urged residents to leave immediately if instructed, warning that "extreme heat and low humidity" have created conditions for the fire to spread with "alarming speed." Officials said the incident underscores the heightened wildfire risk facing Southern California after an unusually active start to the year.