Atmospheric Rivers

Atmospheric Rivers

Atmospheric rivers are narrow, concentrated tendrils of moisture that occur all over the world.

They can be seen from space by observing the movement of water vapor in the atmosphere.

Originating over warm ocean water, they typically travel west to east with the winds.

Atmospheric rivers are very important to California as they provide about 40 percent of the state’s annual water supply.

As the water vapor travels across the Pacific and hits land, it gets forced up into the atmosphere and cools, producing significant rainfall.

NASA studies show during El Niño years, atmospheric rivers that make landfall over California are typically stronger and wetter.

Scientists say this year's El Niño event likely will bring more precipitation to California and some relief for the current drought.

Watch the video to see a visualization of clouds, water vapor and precipitation during winter 1997-98, the strongest El Niño on record.