What exactly is an Atmospheric River? – USGS Communication

Atmospheric rivers occur all over the world in this global view from February, 2017 (courtesy of NASA | Goddard Space Flight Center Visualization Studio).

Atmospheric rivers have been in the news a lot over the past couple of months, from a late October atmospheric river that brought record-breaking rainfall across Northern California to a mid-November storm that led to catastrophic flooding in Washington. A new atmospheric river storm is hitting the Western U.S. now and more are likely on their way. But what exactly is an atmospheric river?