On Monday, January 6th, more than 140 million Americans woke up to frigid temperatures - ones that had not been experienced in at least 25 years. The Midwestern part of the country bore the brunt of the cold. Fort Wayne recorded a bone chilling high of -13°F, while Chicago reported an even lower -16°F. And those numbers were without the wind chill, (the effect the wind has on lowering the temperature), factored in.
By Tuesday, the Arctic chill had spread to the Northeastern part of the country. New York's Central Park broke a 118 year record with a mercury reading of 4°F - Two degrees colder than the previous low set for January 7th, in 1896. Not surprisingly, the extreme weather resulted in disruptions of all kinds - ranging from the cancellation of thousands of flights to the closing of many businesses and schools.
Tens of thousands of Illinois and Indiana residents who had already spent the weekend in darkness thanks to a power outage caused by severe snowstorms, were forced to move into shelters because it was too cold for the utility workers to repair the electricity cables.
As you probably know by now, this cold snap is not the result of a normal winter storm, but something brought on by the polar vortex - A circulation of low-pressure winds that hover over the Arctic moving from west to east or in a counterclockwise direction. These winds are responsible for keeping the frigid cold Arctic air locked in. However sometimes the vortex gets distorted and the cold air manages to sneak out and spread to other regions.
This year when the polar vortex broke, it leaked out cold arctic air above Northeastern Canada and Greenland. The cold air was met by a high-pressure jet system of warm winds from the northeast Pacific Ocean. This helped push the frigid air further south all the way into the United States. Because cold air is dense it travels a long way which is why the freezing temperatures are being felt as far south as Atlanta, which recorded a low of 6°F - The coldest since 1996!
So why does the polar vortex weaken or distort? Interestingly enough some scientists blame it on climate change. As global temperatures have risen, Arctic summers have become increasingly warmer. This causes large amounts of ice to melt, which in turn increases the temperature of the Arctic Ocean. When winter rolls around, the ocean radiates the extra heat back to the atmosphere. This according to experts reduces the temperature differential between the Arctic and the mid latitude regions which includes parts of the United States, causing the polar vortex to weaken. Combine that with certain atmospheric conditions and you get the perfect 'freeze' - The kind the US is currently experiencing.
The good news is that worst is over and most meteorologists expect temperatures to return to normal, by the end of the week. The bad news is that as the polar vortex breaks up, it will distribute its force and make an impact all the way to South West England and Wales where it is expected to bring heavy rain.
Were you affected by the polar vortex? If so, be sure to share your experience by adding your comments below.
Resources: cnn.com, dailymail.co.uk, foxnews.com, businessinsider.com, weatherchannel.com