"I have never seen anything like this," ABC7's Veronica Miracle said in a tweet that included footage of the fiery phenomenon, noting that the blaze had created the fire tornado on a hill near Pine Canyon Road "and it's sucking everything inside."
The fire began Wednesday afternoon and exploded in size within hours on brushy ridges, including some areas that had not burned since 1968, fire officials said. By Thursday morning, the flames had consumed nearly 16.5 square miles of timber and chaparral shrubland. There was no containment of the fire.
No injuries have been reported, but flames have destroyed three structures and were threatening 5,420 others, according to the Los Angeles County Fire Department.
The fire was being fed by tinder-dry brush in steep terrain, but its ferocity on Wednesday approached that of wind-driven blazes that usually erupt when gusty Santa Ana winds arrive later in the year, said county Deputy Fire Chief David Richardson.
The cause of the Lake Fire is unknown.