The big winter (and popular) topic is dusted off very early this season as frigid air plunges south next weekend. But what is the polar vortex, exactly?

WASHINGTON (AP) — Warm Arctic waters and cold continental land are combining to stretch the dreaded polar vortex in a way ...

A polar vortex brings bitterly cold Arctic air into southern Ontario. Here’s what it is and what you can expect.

Deep penetration of cold temperatures and a coastal storm will bring bomb cyclone and polar vortex into your newsfeeds.

Much of the nation east of the Rocky Mountains is hunkered down for what could be the worst winter storm of the season.