A rare split polar Vortex will plunge millions of Americans into freezing temperatures as it's set to blast powerful cold air across the country around Valentine's Day. Forecasters have warned of ...

When unusually warm air last winter disrupted the high-altitude wind stream that normally keeps frigid air over the Arctic, that polar vortex broke down and icy air cascaded south over Canada, the … ...

When unusually warm air last winter disrupted the high-altitude wind stream that normally keeps frigid air over the Arctic, that polar vortex broke down and icy air cascaded south over Canada, the … ...