Answer: the eastward movement of winds and currents in the pacific.
El Nino is an abnormal weather condition which occurs due to the warming of the Pacific ocean near the equator. This occurs due to the fact that the sun warms the water near the equator, this results in formation of massive amount of clouds and rain. The westward- blowing trade winds moves towards the equator. This results in change in the air pressure and wind speed causing warm surface water to move eastwards along the Equator and the currents in the Pacific moves towards the coast of northern South America.