While atmospheric rivers are pretty different from rivers of liquid water down on the ground, they transport enough water to deserve their moniker as rivers. Studies of atmospheric rivers over the Pacific have found that they transport water vapor at a rate equal to 7–15 times the average daily discharge of the Mississippi River. They can be hundreds to thousands of miles long, and though they are narrow in the context of weather systems, 'narrow” can mean up to 300 miles across!Ītmospheric rivers are always flowing somewhere on Earth, even though they don’t consistently stay in one place like rivers on the ground. At any given time, 90% of the water vapor moving toward the poles is concentrated in about 4-5 atmospheric rivers across the globe. Together, these narrow bands of flowing water vapor cover less than 10% of the circumference of the planet.Ītmospheric river storms can affect people around the country and the world. Scientists estimate that atmospheric rivers provide over half of the mean annual runoff on the east and west coasts of North America, France, northern Spain and Portugal, the United Kingdom, southeastern South America, southern Chile, Southeast Asia, and New Zealand. 2. Atmospheric rivers are the largest “rivers” of fresh water on Earth.

Los angeles weather february 2017