A powerful storm is bearing down on California as an atmospheric river drops through the state. While the fast-moving system will affect nearly the entire state on Thursday, Southern California is of high concern as intense rains fall on the heels of devastating wildfires — downpours that could trigger damaging floods and debris flows.

The National Weather Service warned that rain and flooding would intensify throughout the evening until around 10 p.m., bringing the risk of major flooding, debris flows and damaging winds.