Fire crews from Ventura and Los Angeles counties are battling a rapidly growing vegetation fire in Holser Canyon, near Lake Piru, in 100-degree heat. The blaze, called the Canyon Fire, is estimated to be at 1,

The National Weather Service reported that temperatures in the area were hovering around 100 degrees Thursday afternoon.

A 400-acre brush fire burning in Ventura County Thursday afternoon has triggered evacuations in Piru and put nearby communities in the Santa Clarita Valley on high alert as the blaze burns amid a major heat wave that officials warn could foster extreme fire growth and behavior.