pineapple express

The West Coast is once again feeling the effects of the "Pineapple Express". Back in early January one of these "atmospheric river" events, which taps into tropical moisture from as far away as the Hawaiian Islands, brought heavy rains from Washington and Oregon all the way down to southern California. This second time around, many of those same areas were hit again. The current rains are a result of 3 separate surges of moisture impacting the the West Coast. The first such surge in this current event began impacting the Pacific coastal regions of Washington, Oregon, and northern California on...

After more than four years of drought, Californians may wonder where the current rain is coming from. Using satellites, NASA scientists have a unique view of the sources of precipitation, and how it reaches the western United States. Rain is often carried by narrow tendrils of moisture called atmospheric rivers that occur all over the world, shown here in white. The atmospheric rivers that affect the western United States are known as the Pineapple Express because they transport water vapor from as far south as Hawaii to California. When the moisture reaches land, it is forced up over the...