The arctic outbreak that has enveloped the central U.S. is hitting its peak Thursday as frigid temperatures continue to spread south and east across the nation.

Harsh weather moved west as a polar vortex was expected to grip the Rockies and the northern Plains after winter storms pummeled the eastern U.S. over the weekend, killing at least 10 people, includin ...

The polar vortex's icy grip on much of America has Arctic Greenland seeming like a toasty vacation spot by comparison.

Polar vortices exist throughout the year at the poles. In the Northern Hemisphere, the polar vortex expands many times over ...