The polar vortex is currently forming in the stratosphere over the North Pole and is expected to continue to strengthen rapidly as we inch closer to the winter of 2023/2024. But what is the polar vortex, and why should we care about its formation and potential collapse?

In simple terms, the polar vortex is a large area of low-pressure and cold air that surrounds the poles. It always exists, but it becomes stronger and more defined during the winter months. The stratosphere, where this vortex exists, is located above the troposphere, which is where our day-to-day weather occurs.

The vortex typically keeps the coldest air near the poles, acting somewhat like a refrigerator door that keeps the cold contained. However, sometimes the polar vortex can weaken or even collapse, allowing frigid arctic air to spill southward, impacting parts of the United States, Canada, and Europe.

Historically, a collapsing or weakening polar vortex has led to intense and prolonged cold outbreaks. The impacts of these cold air intrusions can be severe, from crippling snowstorms to deadly cold temperatures. A few instances in recent memory:

- 2014: The U.S. experienced an intense winter due to a weak polar vortex. In some areas, temperatures dropped to 30-40 degrees below average.

- 2019: Parts of the Midwest were gripped by temperatures rivaling Antarctica's. Chicago, for instance, saw temperatures plunge to nearly -30°F. Meanwhile, the wind chill factor in southern Minnesota pushed readings down to minus 65°F (-53.9°C) on January 30th.

Such incidents lead to challenges, from transportation disruptions to health risks. Prolonged exposure to extreme cold can lead to frostbite, hypothermia, and even death. Furthermore, these extreme conditions strain energy resources as people turn up the heat and put pressure on infrastructures not designed for such cold.

Oscillations or waves of warm air can occasionally push into the stratosphere, disrupting the normally circular flow of the vortex. When this happens, it can split into multiple smaller vortices or be displaced from the pole. This displacement then allows the cold air that was contained to move south.

Sudden Stratospheric Warming event (SSW), characterized by an abrupt temperature surge in the polar stratosphere, is another mechanism that can cause the polar vortex to collapse. In fact, SSWs are more common during El Niño years, which we are currently in.

As the current polar vortex over the North Pole continues to strengthen this year, it's crucial to be aware of its potential impacts. Understanding the phenomenon can help us prepare for potential disruptions and remain safe during the winter months.