Map shows coldest polar vortex this winter threatening up to 58,000,000 people. ... A polar vortex of Arctic air extends from the top of the world south typically two or three times per winter, ...

The Arctic polar vortex, as defined by the National Weather Service (NWS), is a strong west-to-east wind system that forms in the stratosphere, approximately 10 to 30 miles above the North Pole ...

Dinosaurs of darkness in search of the lost polar world Thomas Rich and Patricia Vickers-Rich Smithsonian Libraries and Archives. Object Details author ... 310 pages illustrations (chiefly color), ...

Map shows polar vortex will grip Rockies and northern Plains with temperatures set to plunge to -42.7 degrees Celsius (Picture: NOAA/National Weather Service) ...