As winter approaches in Wisconsin, people begin to prepare for frigid temperatures and heavy snows. This winter, however, might end up warmer than Wisconsinites are used to. El Niño, a weather phenomenon in the Eastern Pacific, is likely to cause warmer temperatures and reduced snowfall this year.
What is El Niño?
El Niño is the phenomenon of unusually high water temperatures in the Eastern Pacific Ocean. El Niño, which translates from Spanish directly to “little boy” in English, gains the meaning “Christ Child ” when capitalized. According to National Geographic, Spanish immigrants on the Northwestern coast of South America named the phenomenon as such because their communities usually felt the higher temperatures around Christmas time.
El Niño occurs irregularly, and can last for several years. Locally, according to the National Oceanic and Atmospheric Administration, El Niño can have a large impact on fishing. During normal years, cold, nutrient-rich water rises to the surface of the Eastern Pacific in a process known as upwelling. However, During El Niño, warm waters run deeper in the Pacific, trapping vital nutrients like phytoplankton too deep for fish to reach. Without necessary nutrients to sustain life, fish populations decline, often to the harm of local fishermen.
How Will El Niño Affect Wisconsin?
During El Niño, the air above the Pacific is heated by the warm waters below it. This warm air travels towards North America where it pushes the polar jet stream (a river of air which carries cold air to the northern U.S.) north, leading to warmer temperatures in the United States.
According to the National Weather Service, half of the last six strong El Niños caused warmer temperatures in Wisconsin, with temperatures reaching six degrees above average. However, not all El Niño years cause an increase in temperature – some cause the average winter temperatures to drop.
In six out of the seven most recent El Niños, snowfall was near or below average. Snowfall can be similar to normal winters, or even fall to 18 inches below Madison’s 32 inch average. However, snowfall does not always decrease in El Niño years. During one strong El Niño, snowfall was 18 inches above average.
This winter, Wisconsinites may feel higher temperatures than normal. According to a Climate Prediction Center report released on Oct. 19, 2023, there’s a 40 percent chance of above average temperatures in the Madison area. Precipitation is likely to stay around average, but warmer temperatures may mean less snowfall.
