atmospheric river

noun

plural atmospheric rivers

: a concentrated band of water vapor that flows through the atmosphere and that is a significant part of the global hydrologic cycle and an important source of regional precipitation

Environment Canada is working on a new system to rank atmospheric rivers, a type of weather system that damaged highways, flooded farms and homes, and left at least four people dead in southern B.C. earlier this week.

—Wendy Stueck

Atmospheric rivers are relatively long, narrow regions in the atmosphere—like rivers in the sky—that transport most of the water vapor outside of the tropics. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow.

—National Oceanic and Atmospheric Administration

In a typical year, significant atmospheric river storms occur about 10 to 15 times in California. Ultimately, they account for up to 50% of the state's precipitation.

—Paul Rogers

Examples of atmospheric river in a Sentence

Recent Examples on the Web

No atmospheric rivers are currently forecast for Southern California. —Yaakov Katz, Newsweek, 17 Jan. 2025

The concern is borne out of the weather extremes that have whipsawed California in recent years: Punishing heat and dry conditions extending well into the fall, followed by intense rain like the series of atmospheric river systems that pummeled the state in November. —Darrell Smith, Sacramento Bee, 2 Jan. 2025

See weather forecast map Severe weather warnings and watches Another atmospheric river in the Northwest Flooding from heavy rainfall poses a threat in northern California and southern Oregon this weekend, the Weather Prediction Center said. —Jeanine Santucci, USA TODAY, 28 Dec. 2024

The center rated the atmospheric river at moderate to strong, or AR2 to AR3 on a scale of 1 to 5, with 5 being the strongest. —Dennis Romero, NBC News, 15 Dec. 2024

Word History

First Known Use

1993, in the meaning defined above