California residents are being warned to prepare for El Niño

California residents are being warned to prepare for El Niño - as Nasa revealed the phenomenon will be the most watched in history.
There are predictions it could bring as much as 35 inches of rain during the upcoming winter season in some part of California.
However, El Nino this winter will leave a big wet but not necessarily snowy footprint on much of the United States - but won't solve California's drought crisis it has been claimed.
WHAT IS EL NIÑO
El Niño is caused by a shift in the distribution of warm water in the Pacific Ocean around the equator.
Usually the wind blows strongly from east to west, due to the rotation of the Earth, causing water to pile up in the western part of the Pacific.
This pulls up colder water from the deep ocean in the eastern Pacific.
However, in an El Niño, the winds pushing the water get weaker and cause the warmer water to shift back towards the east.
This causes the eastern Pacific to get warmer.
But as the ocean temperature is linked to the wind currents, this causes the winds to grow weaker still and so the ocean grows warmer, meaning the El Niño grows.
This change in air and ocean currents around the equator can have a major impact on the weather patterns around the globe by creating pressure anomalies in the atmosphere.