Frigid Weather Eases Grip Over United States as Icy Blast Begins to Retreat

Meteorologists linked the spell of brutal cold to the so-called polar vortex, a cap of icy air that usually swirls over the North Pole. Changing air currents caused it to slip down through Canada and into the U.S. Midwest this week.

from Top World News- News18.com http://bit.ly/2GgQlSl