GoKawiilEl Niño looks to reach an intensity unprecedented in recorded history.
Characterized by warmer than normal sea surface temperatures in the equatorial Pacific, El Niño occurs every few years. Meteorological agencies and researchers around the world are on high alert because when the heat stored in the ocean is released into the atmosphere, it triggers a chain reaction that affects rainfall, temperatures, and even hurricane activity around the world.
This year’s El Niño has gained strength at an exceptional speed, and it will wreak havoc on everything from fisheries to ski seasons. Not all impacts are bad—the parched Southwest, for example, is likely to see more winter precipitation—but anticipating them is the key to being prepared.
What exactly is happening now, and what might happen in the coming months? Read on to understand what El Niño is, why this one might be a super El Niño, and where its impacts will be most acutely felt.
What Is El Niño?
Declaring El Niño requires meeting a certain threshold of oceanic heat in the Pacific. Specifically, a region known as NINO3.4. It’s an area that sits between NINO3 and NINO 4 if you want to geek out even more. In plain language, it’s a region in the eastern-central tropical Pacific.
The US National Oceanic and Atmospheric Administration uses the three-month average sea surface temperature of the region to determine if an El Niño is in effect. If the ocean is 0.5 degrees Celsius (0.9 degrees Fahrenheit) above normal for three overlapping three-month periods, it’s officially an El Niño.
Other weather agencies do things a little differently. Japan’s Meteorological Agency monitors a slightly different region using its own criteria, while the Australian Bureau of Meteorology’s threshold has an atmospheric component as well.
In addition to warmer oceans, the trade winds that blow from east to westr also weaken. That allows seawater to pile up on the eastern side of the Pacific. In 1997 and 2015—when El Niño events were among the strongest on record—sea levels rose more than 18 centimeters (7 inches) above average.
All this increases the odds of shifts in weather around the world. There’s the aforementioned increase in rainfall in the Southwest as well as a corresponding decrease in Pacific Northwest precipitation. Atlantic hurricane season tends to be milder as well, with fewer storms.
... continue reading