Atmospheric rivers are sinews of moisture from the tropics. The one pictured here appeared over the Northern Pacific on Jan. 3.
An “atmospheric river” is a colorful term for a sinuous plume of moisture that travels up from the tropics — a single plume can carry more water than the Mississippi River at its mouth. But new research shows that atmospheric rivers are also among the most damaging weather systems around.
The atmospheric rivers that soaked California this winter did some good — they ended an epic drought in the state.
“This has been a very active winter, atmospheric river-wise,” reports Jeff Zimmerman of the National Weather Service. “We’ve probably had 10 or more … this winter.” The norm is just a few; being a La Nina year, with cooler water in the eastern Pacific, was part of the reason for the abundance.