An El Nino cycle lasts about one calendar year and occurs about every 3 to 7 years, but they are beginning to happen more often. El Nino cycles predate human industrial activity. During an event cycle, ocean temperatures rise a couple degree causing sea levels to rise. Heated water means more precipitation. Global wind patterns are affected - trade winds are weakened and even reversed. El Nino cycles disrupt the jet stream in North America causing unusual weather. El Nino cycles are responsible for monsoons (heavy rain seasons) in the far East and droughts in Africa. Spanish – the girl
La Nina is the normal condition where the South Pacific ocean is cool. The change from El Nino to La Nina is called the southern oscillation or ENSO.
“It is believed that El Niño conditions suppress the development of tropical storms and hurricanes in the Atlantic; and that La Niña (cold conditions in the equatorial Pacific) favor hurricane formation.”
http://www.pmel.noaa.gov/tao/elnino/faq.html#hurricanes
