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#JustCurious What is an atmospheric river?

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During coverage of the devastating floods in B.C., an atmospheric river was referenced as the reason for all of the rainfall. Our viewer Shawna was #JustCurious what the term means.

WHAT IS AN ATMOSPHERIC RIVER?

An atmospheric river, also called an A.R., is a very common weather phenomenon. It’s how precipitable water from the equator, gets towards the poles. It is often represented on a weather map as a long, skinny line from the ocean in toward land.

These lines of water in the upper atmosphere can be as much water as the Mississippi River. As an atmospheric river hits the coast line they rise, condense and fall as rain or snow.

HOW COMMON ARE THEY?

The National Oceanic and Atmospheric Administration in the U.S. says 30 to 50 percent of the west coast’s moisture comes from atmospheric rivers. They’re not always devastating events. Many times they are just rain or snow events driven by lows and highs in the atmosphere over the Pacific Ocean bringing them into the coast. The same happens on the east coast.

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