A polar vortex is currently hitting the United States, with schools closed in many areas and at least four deaths caused by treacherous conditions.

The week began with a biting cold snap that hammered much of the U.S., the product of a jet stream that slips out of its usual path more often these days.

The images, captured on January 6 by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA’s Aqua satellite, reveal the spread of snow across the Midwestern states. It’s enough to make Old Man Winter blush.

Then, catastrophe in California, with wind-whipped flames ... That means more energy bouncing off and warping or moving the polar vortex, scientists say. And climate change is also messing with ...

A polar vortex is bringing arctic air into the country next week. Forecast maps show when freezing temperatures will sweep through Texas.

A huge swathe of the US has been hit with ice, snow and wind as the polar vortex that dipped south over the weekend kept much of the country in its frigid grip, making many roads treacherous, forcing school closures,

Frigid air that normally stays trapped in the Arctic has escaped, plunging deep into the United States for an extended visit that is expected to provoke teeth-chattering but not be record-shattering

The polar vortex of ultra-cold air usually spins around ... 20 suspected looters arrested in Southern California fire zones Nationwide closures: ‘We are closing underproductive Macy’s stores ...