Polar vortex

A polar vortex is a large area of spinning air.

It is very cold. This spinning air stays near the top and bottom of the Earth.

In the winter, the air gets even colder. This makes the spinning air very strong. It can even spin on other planets like Mars.

Sometimes the spinning air gets weak. When it is weak, the cold air can move. It pushes toward warmer lands.

This brings a sudden cold snap. The air can feel very icy. It can even bring snow and rain.

Scientists watch the air to see it move. It is a big part of our weather.

A polar vortex is a large area of spinning, cold air.

These vortices sit at the top and bottom of Earth. There are two main types. One is in the stratosphere. This is very high up in the sky. The other is in the troposphere. This is the lower part of the air where weather happens.

The vortex is strongest in winter. In autumn, the poles get very cold. This makes the air spin faster. This spin helps keep the cold air near the poles.

Sometimes, the vortex becomes weak. When it weakens, the cold air can move south. This brings a sudden cold snap to warmer places. In 2019, this caused a deep freeze in North America. It was so cold that people could get frostbite in 10 minutes.

In the Southern Hemisphere, the vortex is very steady. In the North, it can break into smaller parts. This happens because of the land and mountains. The vortex also affects the ozone layer. Ozone is a part of the air that protects us.

The vortex can make the ozone layer thinner in the spring.

A polar vortex is a huge region of cold, rotating air. These spinning air masses sit at both of Earth's polar regions.

Scientists describe two different kinds of these vortices. One is the stratospheric polar vortex, which is very high up. The other is the tropospheric polar vortex, where our daily weather happens. Both types of vortex spin in the same direction as Earth. They are important because they control how cold air moves around our planet.

The way these vortices work depends on temperature changes. In the autumn, the poles begin to get very cold. This creates a big temperature difference between the poles and the tropics. This difference causes strong winds to start spinning. A force called the Coriolis effect helps the air spin up into a vortex. The stratospheric vortex is strongest during the winter months. It can be found between 15 km and 50 km high in the sky.

People have studied these spinning air masses for a long time. The tropospheric vortex was first described as early as 1853. Scientists discovered sudden warming events in the stratosphere in 1952. They used tools called radiosondes to see high in the sky. The term became very popular in the news during the winter of 2013–2014. It was also in the news in 2021 because of extreme cold in the United States. These events help us understand how our climate changes over time.

There are many specific facts about how these vortices behave. The stratospheric vortex can experience a sudden stratospheric warming. This can make the air warm up by 30 to 50 degrees Celsius in just a few days. In the Northern Hemisphere, the vortex often breaks into two smaller parts. One part stays near Baffin Island in Canada and the other is over Siberia. In the Southern Hemisphere, the Antarctic vortex is much more steady. It is a single low-pressure zone near the Ross ice shelf.

Understanding the polar vortex helps us predict the weather we feel. When the vortex is strong, it keeps the freezing air trapped at the poles. If the vortex becomes weak, the cold air can push toward the equator. This can cause a sudden cold snap or a deep freeze. In late January 2019, a cold outbreak hit the United States and Canada. Some areas had windchills near -50 °F. The vortex also affects the ozone layer, which is a part of our atmosphere. This can lead to ozone depletion, especially in the spring.

A polar vortex, or circumpolar vortex, is a massive region of cold, rotating air. These large systems encircle both of Earth's polar regions. They also exist on other rotating planetary bodies with low obliquity. Scientists distinguish between two different phenomena: the stratospheric polar vortex and the tropospheric polar vortex. While both rotate in the same direction as the Earth's spin, they differ in size, structure, and seasonal cycles. Understanding these systems is vital because they dictate how extreme cold moves across the globe.

The stratospheric polar vortex is a high-altitude system. It consists of high-speed, cyclonically rotating winds located between 15 km and 50 km high. This vortex forms during the autumn as Arctic or Antarctic temperatures drop rapidly during the polar night. As the temperature difference grows between the poles and the tropics, strong winds develop. The Coriolis effect then causes these winds to spin up into a coherent vortex. This system is strongest during the winter months. It eventually breaks down during the spring as the polar night ends.

A different mechanism drives the tropospheric polar vortex. This system is often defined as the area poleward of the tropospheric jet stream. It extends from the Earth's surface up to approximately 10 km to 15 km. Its equatorward edge is located around 40° to 50° latitude. Unlike the stratospheric version, the tropospheric vortex exists all year long. However, it still reaches its peak strength in winter when polar regions are coldest.

History shows how our understanding of these winds has grown. The tropospheric polar vortex was first described in a publication called "Air Maps" in 1853. Later, in 1952, scientists discovered sudden stratospheric warming (SSW) events. They used radiosonde observations at altitudes above 20 km to identify these events. More recently, the term became a household name during the cold North American winter of 2013–2014. It gained even more visibility in 2021 due to extreme frigid temperatures in the central United States.

The behavior of these vortices can lead to dramatic weather changes. A sudden stratospheric warming can cause temperatures to rise by 30–50 °C (54–90 °F) in just a few days. This event can even reverse the Arctic circulation from counter-clockwise to clockwise. In the Northern Hemisphere, a strong vortex is often elongated with two cyclone centers. One center sits over Baffin Island in Canada, while the other is over northeast Siberia. When the vortex weakens, it can break into smaller, disorganized vortices. This allows cold Arctic air to push equatorward, causing sharp temperature drops.

These shifts have significant real-world impacts. In late January 2019, a deep freeze gripped much of the United States and Canada. During this time, windchills in the U.S. Midwest reached nearly -50 °F (-45 °C). Such extreme cold can cause frostbite in just 10 minutes. In Australia, the vortex is known as a "polar blast" or "polar plunge." It can bring rain, snow, and hail to southeastern regions like Victoria and Tasmania. Additionally, the polar vortex plays a role in ozone depletion. This depletion is most heavy within the vortices, especially over the Southern Hemisphere, reaching a maximum in the spring.

Finally, the polar vortex connects to much larger global systems. Changes in the stratospheric vortex can influence the troposphere below. For example, it can affect the speed of the Atlantic Ocean circulation pattern. A specific area south of Greenland, called the "Achilles Heel of the North Atlantic," is where downwelling begins. Small changes in the vortex can trigger or delay this process. This can alter the Gulf Stream Current and other major ocean currents. Because the world's oceans depend on the movement of heat in the Atlantic, these polar winds can affect climates across the entire planet.