After a long drought, California is suddenly getting pounded with its biggest storm in a decade. Whoa, what's happening? It's all the work of an atmospheric river, a particular weather event that can be devastating when it hits land.

The particular atmospheric river responsible for today's storm is called the Pineapple Express because it runs from Hawaii to the coast of California. Back in 2012, the last time California was hit by a big storm, we about wrote how at atmospheric river works.


Top image: AP Photo/Eric Risberg