Tens of thousands of homes in Washington state lost power Tuesday and downed wires or trees locked some highways as Northern California and the Pacific Northwest started feeling the effects of a powerful atmospheric river event,

A series of storms fueled by a strong atmospheric river is taking aim at the Bay Area and Northern California, intensified by a so-called "bomb cyclone" that promises heavy rain and potential flooding.

KTVU's Mark Tamayo explains how a bomb cyclone differs from an atmospheric river as the Bay Area sees its first major storm of the season this week.