Atmospheric rivers are short-lived, narrow streams of wind that carry water vapor from the tropical oceans to mid-latitude land areas. Atmospheric rivers tend to intensify during El Niño events. This animation shows that atmospheric rivers traveling across the Pacific between November 1, 1997 and March 31, 1998. The El Niño brought strong atmospheric rivers with more precipitation to California. Here, clouds are indicated in white color, water vapor displayed with light blue, and precipitation with green to red.