Since October of 2015 all of Southern California has been preparing for what the National Oceanic and Atmospheric Administration (NOAA) called an “El Niño, amongst the strongest on record.” Forecasts of torrential downpours, mudslides, and gail force winds caused every plucky young field correspondent to salivate with anticipation, and made every single 30-something a recipient of a waterproof flashlight for the holidays from concerned, out-of-state relatives. To date, Southern California is still roughly 2.5” shy of the norm for precipitation.
So what happened?
Well, let’s take a look at the recipe for a normal weather pattern:
First, you take the Earth, tilt it on an axis of about 23.0°, and set it spinning. Add a nice hot equator running through that HUGE patch of Pacific Ocean between the western coast of the Americas and the eastern coast of China and Australia. Toss in a heaping handful of the Coriolis effect, and top the whole thing off with a strong dash of trade winds.
So the equator heats up, the planet spins, heavy cold air from the poles gets sucked down to replace the light warm air around the Earth’s middle, and *POOF*, weather happens.
What also happens is you get a pile up of warm water off the coast of China. Literally a pile of water! The sea surface is normally about 1.5 feet higher and 45° F warmer in Indonesia than Ecuador.
During an El Niño year the trade winds become a little weaker, the deep ocean cold water isn’t being churned to the surface, and there is nothing to hold back all that warm water, so it starts to float back to the western side of the Pacific, bringing with it much needed rain for the coast of California.