Polar vortex: Snow blast returns to US east coast The US east coast has been hit by the second major winter storm of the year, with up to 12in (30cm) of snow, blowing wind and bitter cold forecast. The storm comes two weeks after a weather pattern known as the polar vortex brought heavy snow and record low temperatures to the eastern half of the country. More than 3,000 flights have already been cancelled in the US and authorities warned of hazardous road conditions as snow fell along major motorways.