Weather & Natural Disasters

NASA made an animated map of the rains flooding California

This is the "pineapple express" in action.

The animated map from NASA's Earth Observatory shown above provides a striking visual portrayal of the heavy rains that hit California and the southwestern United States from Jan. 7-10. (The map does not show snowfall.)

The so-called pineapple express is an atmospheric river that travels eastward from the Pacific. It derives its name from its course; it typically originates near Hawaii.

"Atmospheric rivers" are much like what the term suggests: streams of moist air that flow through the atmosphere. But this is not some light fog — these streams can be loaded with up to 15 times the amount of water that flows through the mouth of the Mississippi River, according to the National Oceanic and Atmospheric Administration.

And 30 percent to 50 percent of the western U.S.'s precipitation every year comes from just a few atmospheric river events, notes NASA technical writer Mike Carlowicz, in a blog post.

The animation is made up of satellite precipitation measurements taken by Integrated Multi-Satellite Retrievals for GPM (IMERG), a product of the Global Precipitation Measurement mission, a collaboration between NASA and space and science agencies in several other countries.

NASA does note that actual rainfall measurements on the ground can be even higher than those taken by satellites, so the map could be even bluer than it already appears.

The rains falling over California have replenished water supplies after years of severe drought — about 40 percent of the state is considered drought free, according to an update to the U.S. Drought Monitor on Thursday.

While drought relief is welcome, the sudden rains have led to flooding and storm damage. Up to 2 feet of snow and rain fell in the Sierra Nevada mountains, about 6 inches fell in San Francisco, and bodies of water such as the Russian River in northern California are flooding, after receiving roughly 20 inches of rain last week, as CNBC previously reported.

California floods force residents to evacuate

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