NFL Fans Brave -26C Wind Chill Diehard football fans have braved freezing temperatures and a wind chill of -26C (-14F) to watch an NFL playoff match in Wisconsin. San Francisco players wrapped up in thick red blankets during game breaks The Green Bay Packers took on the San Francisco 49ers at their home field on Sunday night, in one of the coldest American football matches ever played. A phenomenon described as a polar vortex has plunged states in the north and northwest US into a deep freeze, causing transport chaos and school closures. Fans at the Packers' Lambeau Field swaddled themselves in multiple thick layers of clothing and covered themselves with blankets for the tie, which lasted around three hours. Some Packers fans - affectionately known as cheeseheads - wore costumes The 49ers' stars - who are more used to balmy California temperatures - wrapped up on the touchline in signature red blankets. Despite not being accustomed to the inclement weather, they won 23-20, putting them one step closer to February's Superbowl. The weather phenomenon has seen super-chilled air from the Arctic sucked into North and South Dakota, the Great Lakes states and New England, sending temperatures plunging. Thick layers were neccessary for the three-hour game Washington DC has already seen its coldest temperatures for 20 years and several states in the Midwest have recorded their lowest mercury readings for more than a decade. Icy weather is feared to have been a factor that led to a Delta Airways flight skidding off the runway at JFK Airport on Sunday. None of the flight's 35 passengers was injured and the aircraft was safely towed to a gate. Snow at JFK Airport in New York The busy New York airport suspended operations for about two hours due to slick runways. In Chicago, about 1,200 flights were cancelled at the city's O'Hare and Midway international airports. Weather Bell meteorologist Ryan Maue described the current weather conditions as a once-in-a-generation event. With much of the northeast of the country already under thick snow and well below zero, a newly emerging weather system is threatening to cause further misery. The "polar vortex" is an anti-clockwise rotating pool of cold, dense air that forms close to the North Pole, but typically hangs over Canada. The frigid forecast prompted Minnesota public school officials to announce a statewide closure for Monday, marking the first such mass closing in 17 years. The Wisconsin cities of Milwaukee and Madison have also announced school closures to start the week.