Severe weather is set to hit opposite ends of the country this week, with a powerful low pressure system — followed by an atmospheric river — set to bring damaging winds, heavy rain and snow to the Pacific Northwest,

Northern California and the Pacific Northwest are bracing for what is expected to be the strongest storm of the season so far.

A powerful winter storm brewing near the Pacific Northwest known as a bomb cyclone is dragging an atmospheric river.

An atmospheric river and bomb cyclone are what make this storm so powerful — but what do those terms mean? What is an atmospheric river? Atmospheric rivers are no strangers to the western U.S., especially during the fall and winter months.