The 'once in a generation' winter storm has brought bone-chilling temperatures to around 40 million Americans across large swaths of the country.

The snowstorm has coated traditionally warmer parts of Southern USA with a deep lining of white powder, leading to flight cancellations and the closure of at least one airport.

Myriad winter weather alerts and warnings remained in place across the U.S. on Tuesday as multiple states battled storms.