The phenomena of La Niña has reappeared this year, which not only will impact the weather in the United States this winter, but may also trigger significant chain reactions in the global climate, increasing the likelihood of extreme weather events such as rainfall, droughts, and hurricanes.
La Niña is part of the natural climate cycle known as the El Niño–Southern Oscillation (ENSO). This cycle causes fluctuations in sea surface temperatures in the tropical Pacific Ocean near the equator between warm and cold phases. La Niña is characterized by sea surface temperatures in this region being 0.5 degrees Celsius below normal, while temperatures exceeding 0.5 degrees Celsius above normal signify the El Niño phenomenon.
Although La Niña typically occurs every few years, it has persisted for several months during the winter of 2024-2025.
The latest occurrence of La Niña is expected to be of weaker intensity and shorter duration, but it will still be a significant factor influencing this winter’s weather patterns.
On its own, La Niña – the cooling of the Pacific Ocean waters – is not dangerous. However, the climate and weather effects it triggers can be quite perilous. La Niña is associated with a more active Atlantic hurricane season, increased risk of wildfires in certain regions, as well as a higher probability of catastrophic floods or other extreme weather events.
Alex DaSilva, the Chief Hurricane Expert at AccuWeather, a private media company providing commercial weather forecasting services in the U.S., recently mentioned in an online weather forecast that the appearance of La Niña “will lead to an active end to this hurricane season.”
As of October 21, the Atlantic has seen 13 named storms, including 4 hurricanes. Typically, an average hurricane season would produce 14 storms and 7 hurricanes.
According to Matthew Rosencrans, the lead seasonal hurricane forecaster at the National Oceanic and Atmospheric Administration (NOAA), La Niña may impact tropical storm activity in November.
Rosencrans stated in an email to USA Today, “Compared to ENSO Neutral conditions, especially with November during El Niño states, La Niña states are associated with a doubling of November storm activity.”
AccuWeather noted that during the La Niña phase of a natural climate cycle, wind shear in the Atlantic Basin, where tropical weather forms, weakens, increasing the likelihood of more storms forming.
The current hurricane season is set to officially end on November 30.
(Adapted from a report by USA Today)