the Chicago Bears were arch-rivals, Lombardi's most passionate game planning was in preparing for Landry's "Flex". Saturday, on the eve of the game, NFL commissioner Pete Rozelle called Jim Kensil and Don Weiss, the executive directors of the NFL, for an update on the weather conditions. It is suspected that they informed him that Sunday's game time temperature of about was playable. Rozelle, who in June 1966 had seen to it that the AFL-NFL Championship game would always be in a warm weather city, inquired if the game could be postponed until Monday. Predictions held Monday would be even colder than Sunday and the game was not postponed. Little did they know that the cold front would be far colder and would arrive much sooner than expected. The Packers, who had for years eschewed late-season home games because of the cold winters, would play host to the Cowboys in a game that would mark the coldest New Year's Eve in the history of Green Bay, and the coldest title game in the history of the NFL, a record that still stands. David Maraniss recounts in his 1999 Vince Lombardi biography When Pride Still Mattered that Packer safety Willie Wood left his home Sunday morning to find his car's battery frozen and dead. When a local service-station attendant was summoned to start the car, Wood told him, "It's just too cold to play. They're going to call this game off." "The Ice Bowl" Weather The game became known as the Ice Bowl because of the brutally cold conditions. The game-time temperature at Lambeau Field was about , with an average wind chill around ; under the revised National Weather Service wind chill index implemented in 2001, the average wind chill would have been . Lambeau Field's turf-heating system malfunctioned, and when the tarpaulin was removed from the field before the game, it left moisture on the field. The field began to freeze gradually in the extreme cold, leaving an icy surface that became worse as more and more of the field fell into the shadow of the stadium. The heating system, made by General Electric, cost $80,000 and was bought from the nephew of George Halas, George S. Halas. On the sidelines before the game, some Dallas players believed that Lombardi had purposely removed power to the heating coils. The heating system would eventually be given the moniker Lombardi's Folly. The