Bay Area and Northern California residents woke up Wednesday to the arrival of a storm fueled by a strong atmospheric river and intensified by a bomb cyclone off the Pacific Northwest coast. The storm is expected to bring significant impacts including heavy rainfall,

Meanwhile, Southern California this week will see dry conditions amid gusty Santa Ana winds that could raise the risk of wildfires in areas where crews are still mopping up a major blaze that destroyed 240 structures.

A bomb cyclone occurs when cold and warm air collide over the ocean, dropping the pressure at a rapid rate and creating intense weather. On the East Coast, that can mean vast quantities of snow. Here on the West Coast, it can usher in buckets of rain.