El Niño is a climate anomaly which occurs in the Pacific between the west coast of South America and Southeast Asia (Indonesia, Australia) at intervals of 2-7 years. During an El Niño event, the prevailing trade winds weaken and the equatorial countercurrents strengthen. This causes warm surface waters from the Indonesian region to flow eastward, displacing the cold water of the Humboldt Current, which in turn leads to disruption of the temperature and moisture regime. Large amounts of precipitation (up to 4000 mm in a month) occur in the coastal deserts of Peru and northern Chile. More rainfall than normal also falls on the islands east of Indonesia, while Indonesia itself and Northern Australia suffer drought. In some cases, further-ranging effects of El Niño have been observed: increased precipitation in southern Argentina, the southern states of the USA and northern Mexico, decreased precipitation in southeast Africa, Korea, southern Japan, and northeast Brazil.
rain fall (up to several 100 mm in a few hours), frequently causing flooding.
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