The Upper Midwest and Northern Plains have been hit by Canada's freezing temperatures. On Thursday, Dec. 4, wind chills between negative 10 to negative 25 degrees will be expected, and the cold temperatures are expected to continue into Friday, Dec. 5 for those in the eastern U.S.

A polar vortex broke, and severe temperatures are set to dominate most of the United States, including the Midwest, in the coming days.

Arctic wind patterns create a sort of wall around the pole that prevents frigid air from trickling southward. That wall that keeps cold air contained is called polar vortex. Commonly, though, people refer to polar vortex when that retaining wall breaks or weakens and Arctic air slips out of the pole and into other regions.

It is forecasted to be cold in the Bay State as a result of the breaking, or "displacement" of the polar vortex. According to AccuWeather, temperatures in Massachusetts won't be above 36 degrees until Wednesday, Dec. 10.

A strong polar vortex doesn't cause cold weather — it does the opposite. Here's what to know about polar vortices, how they work.

Some states are gearing up for subzero temperatures. Here's what to look out for.

More than 200 million Americans are bracing for a historic Arctic outbreak as a displaced polar vortex sends frigid air cascading southward across the continental United States. Temperatures are plummeting into dangerous territory from the Dakotas to the I-95 corridor,

Some sates saw subzero temps. Here's how cold it got in all states, and why it got so cold.

As we head into the polar vortex, meteorologists are calling for up to a foot of snow in some parts of the U.S.