Tech & Science dictionary
atmospheric river
[ at-muhs-fer-ik riv-er ]
What is an atmospheric river?
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.
Example: The weather report said that an atmospheric river is expected to bring some much-needed rain to the region.
Where does atmospheric river come from?
The coining of the term atmospheric river can be traced to the Massachusetts Institute of Technology climate scientists whose research was responsible for the first descriptions of the phenomenon in the early 1990s. The name likens the phenomenon to a river because of the similarity in the transport and flow of water.
Examples of atmospheric river
Who uses atmospheric river?
The term atmospheric river is typically used by climate scientists and meteorologists, though it occasionally gains mainstream attention during major precipitation events related to the phenomenon. People who live in areas commonly affected by atmospheric rivers, such as the West Coast of the US, are more likely to be familiar with the term.
“Category 4 atmospheric river” sounds more like a Star Trek planetary survey report than it does PNW weather status.
— Isaac Watson (@ibwatson) February 28, 2022
first “the heat dome” and now “an atmospheric river”
portland weather seriously going full professional wrestling like we don’t have enough to worry about
— JLJ @ 👹🦁⚒️ (@jameslucasjones) February 28, 2022
this week in california we've had record breaking heat, wind gusts up to 100mph, red flag warnings and small wildfires, rain, and today, frost. later today we're going to get an atmospheric river and people are already under evacuation for flash floods and debris flows
— Julia Carrie Wong (@juliacarriew) January 26, 2021
Note
This is not meant to be a formal definition of atmospheric river like most terms we define on Dictionary.com, but is rather an informal word summary that hopefully touches upon the key aspects of the meaning and usage of atmospheric river that will help our users expand their word mastery.