||| FROM DICTIONARY.COM |||
An atmospheric river is a long, thin stream of water vapor that moves through Earth’s atmosphere.
The term likens the phenomenon to a river due to the similarity in the flow of moisture from one place to another. However, the water in an atmospheric river is in the form of water vapor, as opposed to the liquid water that constitutes rivers.
Atmospheric rivers typically begin in the skies over tropical areas and their direction and movement is determined by wind and weather patterns. Once an atmospheric river reaches an area that’s cold enough, the water vapor cools and condenses, resulting in rain or other forms of precipitation.
Atmospheric rivers are a common atmospheric feature of Earth’s climate. There are usually more than 10 of them in the atmosphere at any given time, and they often occur in roughly the same patterns. One of the more well-known examples of an atmospheric river, nicknamed the “Pineapple Express,” spans from Hawaii to the western portion of the United States and Canada.
Atmospheric rivers usually only gain mainstream attention when they release significant precipitation, especially when that precipitation causes flooding or contributes to other natural disasters, such as mudslides.
