Parts of Los Angeles County will be under evacuation warnings starting Thursday evening as a complex storm system moves in.

© The New York Times

A geomagnetic storm made the aurora borealis visible across a swath of the United States again on Wednesday, illuminating the skies as far south as Arizona.

© Matterhorn Ski Paradise and Feratel/UGC, via Reuters

The storm is expected to move quickly through Northern California, but forecasters are concerned that it will stall in the southern part of the state.

© The New York Times