A massive winter storm among the worst the United States has seen in decades dumped snow, ice and sleet across a huge swath of the country yesterday, knocking out power and grounding thousands of flights. The storm – one of the largest winter storms since the 1950s, according to NASA stretched for more than 3,000 kilometers from Texas to the northeastern state of Maine, and forecasters warned it could be several days before it abated. Blizzard, winter storm and freezing rain warnings were issued for more than half of the 50 US states, and tornadoes and major thunderstorms were also predicted along the southern end of the storm in Louisiana and Mississippi.High winds and freezing rain turned roads into deadly ice rinks and knocked down trees and power lines. States of emergency were declared in Illinois, Indiana, Missouri and Oklahoma and the National Guard was called out to help rescue stranded motorists. Thousands of schools and government offices were closed and many businesses shut down early as well. Flight Aware reported that airlines grounded nearly 6,500 flights on Tuesday, about 20 per cent of US commercial flights and protectively canceled another 3,600 today.