Atmospheric rivers are more common during the winter months, but officials are warning people not to let their guard down.

Map of Sierra Nevada in California showing how an atmospheric river develops. Most atmospheric rivers are weak and do not cause damage. In fact, they can provide much-needed rain or snow.

When a bomb cyclone meets an atmospheric river, the result is like an out-of-control fire hose A powerful storm hitting the West Coast combines these weather phenomena for a wet week in many areas.

"That moisture plume, known as an atmospheric river, will be tropical in nature and originate from the Caribbean," AccuWeather Senior Storm Warning Meteorologist William Clark said in the report.

A graphic from AccuWeather shows the setup of the current atmospheric river affecting the U.S. A graphic from AccuWeather shows the setup of the current atmospheric river affecting the U.S ...

In the 1860s, California had to move its capital out of Sacramento because of an atmospheric river flooding. These events aren’t just a California thing. They actually happen all over the United ...

LOS ANGELES—An atmospheric river storm is pounding parts of California on Friday after wreaking havoc throughout the state this week, bringing severe storms, mudslides and feet of snow.

Strong winds and rain from the atmospheric river storm hitting the Bay Area caused thousands of PG&E customers to lose power on Wednesday, the utility said. The largest outages were reported in ...

Here's an explanation of how they form, their size and potential impacts. WHAT IS AN ATMOSPHERIC RIVER? The weather system occurs all over the world. It starts when a large amount of water vapor ...