[In Depth] California rains put spotlight on atmospheric rivers
In just a few months, California has moved from extreme drought to dangerous flooding, thanks to atmospheric rivers: long, narrow ribbons of water vapor in the sky. Just a few hundred kilometers wide, atmospheric rivers stretch thousands of kilometers from the tropical oceans toward the poles, carrying up to 20 times as much water as the Mississippi River. That moisture gets tugged along by the windy paddle wheels of spinning storms ahead of its path. When the atmospheric rivers make landfall and the vapor condenses, they can release a staggering amount of rain and snow. Scientists are now working to unravel their physics so that they can provide better forecasts, both now and in a future, hotter world. For dry, midlatitude regions like California, any changes could have a profound impact. Author: Julia Rosen