Winter's chill will settle into the U.S. this week, but temperatures could always be colder! When the polar vortex weakens, even colder air can make its way south as if Mother Nature left the refrigerator door open.

We've all heard of it, but what is the polar vortex? The polar vortex is a large and very cold area of low pressure that surrounds the poles. It always exists, but it becomes stronger and more defined during the winter months. The stratosphere, where this vortex exists, is located above the troposphere, which is where our day-to-day weather occurs.

The vortex typically keeps the coldest air near the poles as it swirls, keeping the cold air contained. However, sometimes the polar vortex can weaken or even collapse, allowing frigid arctic air to spill southward, impacting parts of the United States, Canada, and Europe.

Historically, a collapsing or weakening polar vortex has led to intense and prolonged cold outbreaks. The impacts of these cold air intrusions can be severe, from crippling snowstorms to deadly cold temperatures. Can you see any cold air outbreaks on the TemperatureRadar?

Such incidents lead to challenges, from transportation disruptions to health risks. Prolonged exposure to extreme cold can lead to frostbite, hypothermia, and even death. Furthermore, these extreme conditions strain energy resources as people turn up the heat and put pressure on infrastructures not designed for such cold.