What is the Pineapple Express?
Atmospheric rivers are narrow regions in the atmosphere that transport much of the moisture from the tropics to northern latitudes. Atmospheric rivers are part of the Earth’s ocean water cycle, and are tied closely to both water supply and flood risks.
A well-known example of a strong atmospheric river is called the “Pineapple Express” because moisture builds up in the tropical Pacific around Hawaii and can wallop the U.S. West Coast with heavy rainfall.