An arctic cold front with temperatures down to minus 40 degrees Celsius had plunged large parts of the USA into chaos shortly before Christmas. The situation in Buffalo and the surrounding areas of Erie County was particularly dramatic. Several bodies were found in their cars or under snowdrifts.

In view of the now rising temperatures, the authorities warned of a thaw on Wednesday. "As temperatures increase, we expect snow to melt and potential rapid-melt flooding to occur," Erie County Administrator Mark Poloncarz said.

The snowstorm has also been causing chaos in air traffic for days. The airline Southwest Airlines, which had to cancel more than 2,500 more flights on Wednesday, is particularly affected.