Two fast-moving wildfires that exploded in the Southern California hills have claimed nine lives and forced thousands to flee their homes, including the entire city of Malibu.

Fanned by ferocious Santa Ana winds and fuelled by dry tinder, the fires thus far have proved to be unstoppable, operating at flash-flood velocity. The big wildfire in Southern California, known as the Woolsey Fire, quadrupled in size by Friday evening, covering more than 22 square miles, with no containment.