The Godzilla El Niño. The Wicked El Niño. The Super El Niño. “Bruce Lee.”
Whatever you want to call it, this year’s El Niño is shaping up to be one of the strongest on record. But no matter what the predictions say, there’s still huge uncertainty: When will the rain come? How much will we get, and where? As Bren Professor Jeff Dozier said: “Want to know what El Niño will look like? Ask me in the spring.”
So do we actually know anything?
Here are 5 things we can be sure of this El Niño holiday season:
1. It’s Not Coming. It’s Already Here.
Heavy rains and warmer coastal temperatures don’t define El Niño (the “strong” El Niño of 1965-1966 actually had lower than average rainfall). Instead, it’s about warmer temperatures in the equatorial Pacific Ocean, most commonly measured in Niño zone 3.4.
Not familiar with Niño Zone 3.4 it? It’s located here:
If sea surface temperatures are recorded more than+ 0.5 degrees Celsius above the average for three consecutive months, it is an El Niño year. Until last month, the highest temperature in this region was + 2.8⁰ C, which corresponded with the 1997-1998 El Niño—the strongest in recorded history.
This November the temperature was measured +3.1⁰ C.
This means that this El Niño isn’t coming, it’s here. And it is breaking records.
2. It’s both an oceanic and atmospheric phenomenon.
El Niño Zone 3.4 is only an indicator of El Niño’s presence and strength. These measurements point to more complex interactions occurring between the ocean and the atmosphere that can have significant impacts on our global climate.
This video sums it up quite nicely.
But to cover the basics:
- During an El Niño event, the equatorial trade winds slacken or reverse. So instead of winds blowing warm water east to west toward South Asia, the warm water shifts eastward back toward South America.
- The changes in ocean heat available to the atmosphere result in atmospheric pressure changes that drive atmospheric circulation, wind, and precipitation.
- These changes also alter the path of atmospheric jet streams which affect weather patterns around the world
3. It will be wetter…and drier
As Bren Professor Jeff Dozier likes to ask his students each year in the ESM 203 Earth System Science class: Is an El Niño wet or dry?
During a strong El Niño year—as we are anticipating this winter— we generally expect to see this:
California, western South America, and parts of East Africa are typically wetter, while the Midwest and Northeast of the US remain milder and drier, along with much of SE Asia, Australia, and Southern Africa.
In fact, 4 out of 5 “strong” El Niño events in Southern California (and 5 out of 5 in Santa Barbara County) have had higher than average precipitation, so chances are we will be getting rain this winter. (http://ggweather.com/enso/enso_myths.htm)
But overall, one third of El Nino events report average rainfall in California, while another third report lower than average rainfall. There are no guarantees for “wet”. So, if you are ever in doubt while discussing the impacts of an El Niño, a good rule of thumb is: “not always and not everywhere.”
Which brings us to…#4.
4. It’s not just about rain in California
As Californians wait expectantly for the much needed rains of El Niño, many other regions of the word are not quite so eager. With fires in Indonesia, coral bleaching in the Caribbean, flooding in India, droughts in Ethiopia, the global impacts of El Niño are affecting everything from crop yields and food-prices, to city infrastructures and local economies. The 1997-1998 El Niño is estimated to have cost the global economy $30-$45 billion in losses across the agriculture, fisheries, and energy industries.
Here is a map from the Wall Street Journal of “the price of El Nino”:
5. There will be surprises!
No two El Niño events have ever been the same, which makes predicting their behavior difficult. There are many other players, particularly when it comes to winter weather. The Arctic Oscillation plays a big role on the East Coast, while the Madden-Julian Oscillation has direct impact on storms in the Pacific Northwest, both unrelated to El Niño, but can influence the “normal” weather anomalies of El Niño.
There is also the simple challenge of technology and predicting the future. A recent article from San Jose Insides explained. “Even with advanced technology—which includes some 70 buoys moored in the depths between Japan and the California Coast—climate prediction is a field riddled with unknowns, probabilities and conservative estimates. The saying goes, climate is what you predict and weather is what you get. But one thing is certain: it’s going to rain this winter. Possibly a lot.”