The US Midwest is grappling with excessive cold and freezing temperatures. The death toll has gone up to at least 21 and normal life has been hit. According to reports, the last time the US was this cold was in 1994. And all this is being attributed to a phenomenon called Polar Vortex.

So, what is Polar Vortex? 

The Polar Vortex can roughly be defined as a large area of low pressure and cold air surrounding both the North Pole and the South Pole. The dictionary defines vortex as “a mass of air or water that spins around very fast and pulls objects into its empty centre”. Imagine what a whirlpool or a tornado looks like, and you will get a fair picture of a vortex.

Polar Vortex, thus, can be defined as a whirlpool or a tornado occurring at either of the two poles (North Pole and South Pole).

It is an occurrence that always exists near the two poles. It is at its peak during the winters while it fades down during the summers.

Occasionally it happens that during winters in the Northern Hemisphere, the Polar Vortex expands, sending cold air southwards with a lot of power, propelling very cold air with it.

Polar vortex rotates counter-clockwise at the North Pole and clockwise at the South Pole.

The very first instance of Polar Vortex was reported in January 2014. That time, temperatures had plummeted to as low as minus 51 degrees Celsius in some places in the Midwest and Northeast US.

This time, it is being said, higher than usual temperatures in the Arctic region have forced the bitterly cold winds to travel south, affecting the temperatures in the US and Canada.