Will the current La Niña unleash an "Ice Age" winter? With cold, snow and extreme weather on the way?
The European and Mediterranean, as well as the North American winter, can experience significant fluctuations when a climate phenomenon called La Niña occurs.
This natural phenomenon, characterized by anomalous cooling of the surface waters of the central-eastern Pacific Ocean, has global implications and affects atmospheric and climatic patterns in different parts of the world, including Europe.
What is La Niña and How Does It Develop?
La Niña is the opposite climate phenomenon to the more familiar El Niño; both are part of the phenomenon known as ENSO (El Niño-Southern Oscillation). During La Niña, the trade winds intensify and drive the warm surface waters towards Asia, while colder water in the eastern Pacific reaches the surface.
Photo courtesy of NOAA
This process leads to a significant cooling of ocean temperatures in this region, which changes the atmospheric dynamics on a large scale.
Global Effects
The effects of La Niña are not limited to the Pacific Ocean. On a global scale, La Niña can influence precipitation and temperature patterns and change the behavior of jet streams and other atmospheric systems. This may lead to an increase in precipitation in some regions and droughts in others, affecting the climate worldwide.
The Impact of La Niña on Europe and the Mediterranean
When La Niña is active, Europe and the Mediterranean may experience an unusual winter, with climatic trends that can vary significantly depending on the strength and duration of the phenomenon.
Wavy Jet Stream and Arctic Cold
One of the main effects of La Niña on Europe is its influence on the jet stream, a fast flow of air that runs from west to east in the northern hemisphere and plays a crucial role in determining the weather.
During La Niña, the jet stream tends to become wavier, with the formation of large waves that allow cold Arctic air to penetrate into Europe. This configuration can lead to periods of intense cold, particularly in the northern and central regions of the continent, with temperatures that can be well below the seasonal average. Scandinavia, Russia, and Eastern Europe are often the worst affected areas, but Western Europe can also experience cold spells.
Increase in Snowfall and Extreme Weather Conditions
As temperatures drop, the likelihood of snowfall increases, especially in the northern areas of the Alps and other mountain regions.
However, areas at lower altitudes could also experience significant snowfall during a La Niña-influenced winter. The United Kingdom, Germany, France, and, in some cases, northern Italy could experience more frequent and more abundant snowfall than average.
In addition, the wavy configuration of the jet stream can lead to the formation of particularly intense low-pressure systems that can cause winter storms with strong winds, storm surges, and intense precipitation. These extreme phenomena could affect the western coasts of Europe, from Portugal to Norway.
Its Impact on North America:
La Niña, according to NOAA (the National Oceanic and Atmospheric Administration), is a “cold event.” Specifically, La Niña is all about the wind; during a La Niña pattern, the trade winds over the Pacific Ocean are stronger than during an El Niño year—which is what we experienced this past winter. These strong trade winds typically result in warmer and drier winters for the south, cooler winters in the north, and heavy rains and flooding throughout the Pacific Northwest and Canadian Pacific.
While the official preseason report from NOAA won’t be published until August, OpenSnow Chief Operating Officer and Meteorologist Sam Collentine shared a sneak peek: “The effects of La Niña tilt the odds in favor of much of the western U.S. receiving average to above-average snowfall during significant events. Again, though, the pattern doesn’t hold 100 percent of the time.”
The Uncertainty of the Phenomenon
Despite the general trends associated with La Niña, it is important to emphasize that each event is unique and its effects may vary. Other factors such as the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) may interact with La Niña and further alter climate patterns in Europe and the Mediterranean.
Therefore, the exact prediction of La Niña's impact on the European winter remains complex and dependent on many variables.
To summarize:
La Niña has the potential to make the European and Northamerican winter more dynamic and unpredictable, with the possibility of intense cold, abundant snowfall, and extreme phenomena, especially in the northern and central regions.
