The heat wave and record drought affecting more than a dozen states has people asking a common question in this season of extreme weather: Why? The answer is likely a weather phenomenon called La Niña.

States across the U.S. are grappling with a debilitating drought that is killing off crops and starving livestock. The reason is La Niña, which cools off waters in the equatorial Pacific and shut off the southern pipeline of moisture, David Miskus of the National Oceanic and Atmospheric Administration told The New York Times.

La Niña, which means the little girl in Spanish, is the opposite of El Niño, which entails an abnomal warming of oceanic waters and means little boy. La Niña typically causes wetter than normal conditions across the Pacific Northwest and dryer and warmer than normal conditions across much of the southern tier while El Niño usually leads to increased rain in the south, according to a Web site run by the National Oceanic and Atmospheric Administration.

The terms were believed to have been coined by fisherman off the coast of South America. They are both naturally occuring climate patterns that tend to alternate with one another.