This is Scientific American's 60 Second Science.

I'm Christopher in Tagyatta.

Back in January, one of California's oldest and most iconic residents keeled over.

The Pioneer Cabin Tree, a giant Sequoia in Calaveras. iconic over by high winds, delivered by what's called an atmospheric river, a long stream of water

vapor in the atmosphere, 100 miles wide. And these systems might be thought of as some of the biggest

rivers on Earth.

You could kind of pose it that way, yeah.

Duane Walliser, an atmospheric scientist

at the Jet Propulsion Lab.

An atmospheric river will carry the same amount of water vapor

as say 15 to 20 Mississippi rivers.

Walliser and his JPL colleague bin Gwan

developed an algorithm to detect atmospheric rivers in historical data

so they could connect the sky flow to extreme events on land.

And they found that if you look at just the top 2% of the most extreme wind and

rain and snowstorms in the world's mid-latitude regions,

atmospheric rivers are linked up to half of them.

And of the 19 wind storms in Europe

they cost insurance companies the most money,

billions of dollars in damage,

atmospheric rivers were behind three quarters of those events.

The studies in the journal Nature Geo Science.

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