The arctic blast that settled over the much of the U.S. has delivered frigid temperatures, snow, ice, and piercing winds that have broken records and should continue breaking records.

But what exactly is an arctic blast?

An arctic blast has alternate names for weather fronts called a polar vortex or a blue norther. A polar vortex is a low-pressure area that typically forms around the North and South Poles that strengthens and weakens year over year. A strong vortex is typically a well-defined cold front that is contained and bordered around the arctic regions. AccuWeather defines a blue norther as a "strong cold front marked by a sudden and drastic decrease in temperature."

Weaker vortexes are more scattered and disorganized fronts that can push farther south or north, depending on which pole the front comes out of. These weaker vortexes lead to cold fronts that can bring a combination of cold temperatures, winds and possibly snow.

It is this front that led to the arctic blast that 240 million Americans have had to contend with over the past few days. The Midwest and Northeast have faced the brunt of the blast since it hit Monday evening as temperatures began dropping sharply while some got buried under early season snow. This sharp and immediate drop resulted in traffic problems, delayed or canceled flights and school closures across states like Michigan, Ohio and Illinois.

The worst has been a series of car accidents across the Midwest, resulting in four confirmed deaths in separate accidents.

The National Weather Service updated its warning Wednesday morning, comparing it to the blue norther front that engulfed the Great Plains and east coast in 1911.

The current front has delivered similar record-breaking cold fronts and snowfall while it continues pushing east, past New England by Thursday. While some regions are still forecasted to have some lingering cold snaps, temperatures are expected to rise.

Winter snowfall in Chicago Residents of Chicago dig out after a snowstorm passed through the area on Jan. 19, 2019 in Chicago, Illinois. A winter storm is set to slam the U.S., expected to affect an anticipated 90 million people nationwide. Photo: Scott Olson/Getty Images