Record-breaking cold and heavy snowfall: Is this severe weather truly caused by a polar vortex? (video)

This week, the United States is experiencing record-breaking cold and heavy snowfall as yet another winter storm sweeps through several central and eastern states. Meteorologists predict that the next few days will bring incredibly cold winds, with temperatures ranging from -34 to -51 degrees Celsius. The storm is also expected to deliver substantial snowfall to millions of residents, with precipitation amounts anticipated to reach 31 centimeters, according to Live Science.

Many attribute the onset of the winter storm to the polar vortex—an area of low pressure and cold air circulating around the North and South Poles in the stratosphere, a layer located 12-50 kilometers above the planet's surface. However, scientists are not entirely convinced that the polar vortex is responsible for the winter storm in the U.S.

According to Paul Pastelok, a lead long-range forecaster at AccuWeather, the high-pressure area over northern Canada has been the primary factor driving the cold air southward into the central plains and the Mississippi Valley. This cold air then collided with warmer temperatures further south, generating storms.

Experts believe that the February winter storm was triggered by a sharp contrast between warmer temperatures along the Gulf Coast and colder air moving through the northern Rocky Mountains, northern plains, and Canada. This stark contrast created a stormy weather zone that separated the two air masses, leading to this chaos.

As stated by Amy Butler, a climate scientist at the National Oceanic and Atmospheric Administration (NOAA) Chemical Sciences Laboratory, the role of the polar vortex in the February storm remains unclear.

Some studies have already indicated that the stretching of the polar vortex is linked to an increase in cold air invasions into the central and eastern United States. However, Butler acknowledges that the causal relationship is still not clear: it is possible that the vortex is simply reacting to the high-pressure area over the Arctic—high pressure could essentially stretch the lower vortex.

The expert believes that the high pressure in the Arctic—a part of a pressure change known as Arctic Oscillation—is likely the cause of the cold weather in the central United States.

Butler notes that this high-pressure area over the Arctic represents a buildup of air mass that helps shift the jet stream southward, allowing cold Arctic air to spread southward.

Some studies suggest that warming in the Arctic may disrupt the polar vortex. For example, a 2021 study indicated that Arctic warming was likely a significant factor in the stretching of polar vortices that brought extreme cold to North America in 2021.