What is "El Nino" and what are its effects?

[music fades in]

Welcome to CoreFacts, where we're always short on time and big on science. I'm Brian Campbell. Today's question is...

What is "El Nino" and what are its effects?

El Nino is a natural phenomenon that recurs every few years during which the trade winds, which normally blow from east to west across the Pacific Ocean just north of the equator, lose their intensity. This allows the warm water that is typically around Indonesia to move east to the area just west of the coast of South America near Peru and Ecuador. The change in the typical Pacific Ocean water temperatures causes worldwide changes in normal weather patterns. In the United States, El Nino causes winter temperatures to be warmer than normal, and floods occur in California and in the southeastern states. Likewise, El Nino was responsible for the hot and dry summer of 1998 in Florida that caused the extensive wildfires. El Nino is so named because the effects of the warmer water off Peru are usually noticed near Christmas time. El Nino is Spanish for "Christ child."

And now you know. Join us again every week for a new CoreFact. For other CoreFacts, or for CoreCast, our in-depth science podcast, go to usgs.gov/podcasts. If you'd like to have a question featured on our show, give us an email at corefacts@usgs.gov or a phone call at 703-648-5600. Remember, long distance fees do apply.

CoreFacts is a product of the U.S. Geological Survey, Department of the Interior.

[music fade out]