A life-threatening, widespread windstorm that could be one of the most destructive to hit Southern California in over a decade will roar to life Tuesday and also create extremely dangerous fire weather conditions.

Millions of people across Southern California are under a Red Flag warning as a dangerous windstorm starting Tuesday could bring widespread destruction and extreme fire risk to the area, with emergency services braced to provide a huge response.

Strong winds — with gusts as high as 79 mph in the San Gabriel Mountains — began blowing their way through Southern California on Tuesday morning, Jan. 7, leading to the possibility of downed trees and wires, power outages and dangerous fire weather.