A polar vortex dipping down from Siberia will bring a cold front with frigid temperatures to nearly 300 million Americans. See maps of the arctic blast.

The polar vortex is a ring of cold air that typically circles the Arctic. A strong jet stream essentially acts like a fence, keeping it locked there. If there's any weakening in the jet stream (the fence), the frigid air can become unstable and spill out. This sends the normally trapped cold air much farther south.

The most unusually cold air in the Northern Hemisphere will be over the United States early next week, bringing dangerously frigid conditions.

Snow and winds are likely to trigger flight cancellations and cause headaches for people traveling to DC for Inauguration Day.

People living "basically anywhere from the Rockies eastward" will see extremely cold temperatures over the next several days, a meteorologist says.

AP) — A huge swath of the U.S. was blasted with ice, snow and wind on Monday as the polar vortex that dipped ... wardrobes for hats and gloves. Washington, D.C., received heavy snow as President ...

Models are hinting at the possibility for snow, freezing rain, and ice pellets to fall from central Texas across the northern Gulf Coast into portions of northern Florida. While the setup looks favourable for snow and ice, it’s extremely hard for wintry precipitation to fall in this part of the world.

The polar vortex of ultra-cold air usually spins around the North Pole, but it sometimes plunges southward into the U.S., Europe and Asia. Studies show that a fast-warming Arctic is partly to blame for the increasing frequency of the polar vortex extending its grip.

Under the Rotunda of the U.S. Capitol, Donald Trump was again inaugurated, this time as the 47th president of the United States, capping a historic return to power that serves as resounding rebuke to the established political order.

A brutal polar vortex is set to bury the Big Apple in snow Sunday and then deliver deadly single-digit temperatures that will feel like 15 degrees below zero.

A huge swath of the U.S. was blasted with ice, snow and wind on Monday as the polar vortex that dipped ... wardrobes for hats and gloves. Washington, D.C., received heavy snow as President-elect ...

Most of the country will likely be hit by an arctic blast this weekend into early next week as the polar vortex ushers ... reach the single digits in Washington, D.C., Philadelphia and Boston.