A powerful blast of cold air from the Arctic is expected to sweep through much of the United States, bringing snow and ice to nearly 30 states and impacting nearly 160 million people, forecasters warn.
The cold front is expected to ramp up on Thursday in the southwest, before pushing into the East Coast over the weekend.
Meteorologists say temperatures could plunge well below freezing in some areas as the frigid northern air, known as the Polar Vortex, settles over the country.
Transportation officials, including airport authorities in several major cities, are warning travellers to brace for significant delays amid the severe winter weather.
The weather system is expected to take shape in Texas and New Mexico before moving eastward, blanketing cities including Memphis, Nashville, Washington DC, Baltimore, Philadelphia and New York with snow.
