Stratospheric polar vortex changes still trigger brutal U.S. winter cold snaps and extreme weather despite a warming climate.

Even in a warming climate, brutal cold snaps still hammer parts of the U.S., and a new study uncovers why. High above the ...

JERUSALEM, July 11 (Xinhua) -- An international research group has found that extreme cold snaps in the United States are driven by disruptions in a high-altitude Arctic air mass called the polar ...