As the winter storm pummeling much of the eastern part of the United States begins to let up, a meteorological phenomenon known as an atmospheric river is forecast to bring days of rain and heavy winds to the West.
An atmospheric river is a relatively narrow channel of wind, hence the "river," that transports water vapor from the tropics to the West Coast. Powerful rivers that arrive at just the right angle of the coast can carry all the way to the Sierra Nevada.
