(Click to enlarge) Rain clouds move in over downtown Los Angeles, California on March 2, 2015. A strong El Niño could bring more rain to California, and could even cause flooding. (Credit: Lucy Nicholson/REUTERS,CORBIS)
(From National Geographic / by Willie Drye) — El Niños have been occurring at least since the end of the last Ice Age about 10,000 years ago. But scientists have only been able to effectively monitor the events since the advent of weather satellites. In that time, there have only been two strong El Niños—one in 1982-83 and another in 1997-98.