This is the best image we've seen of how the "polar vortex" has infiltrated the U.S., causing the cold snap we are experiencing. Blue is the freezing line:
The image above was tweeted out by AccuWeather's Anthony Sagliani. He created it using the Living Earth app (available for iPhone, iPad and Mac).
SEE ALSO: Here's What The 'Polar Vortex' That's Hitting The US Actually Is
SEE ALSO: CHART: Here's How Long You Can Stay Outside In Extreme Cold Temperatures Before Getting Frostbite