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first event
The cycle begins when warm water in the western tropical Pacific Ocean shifts eastward along the equator toward the coast of South America. -
second event
Normally, this warm water pools near Indonesia and the Philippines. -
third event
During an El Niño, the Pacific's warmest surface waters sit offshore of northwestern South America. -
el nino
Forecasters declare an official El Niño when they see both ocean temperatures and rainfall from storms veer to the east. -
el nino
Experts also look for prevailing trade winds to weaken and even reverse direction during the El Niño climate phenomenon. These changes set up a feedback loop between the atmosphere and the ocean that boosts El Niño conditions.
