GREEN BAY, Wis.— The fabled tundra of Lambeau Field will be far from frozen when the Green Bay Packers and Minnesota Vikings clash in Saturday’s NFC playoff game.

Temperatures are expected to be in the teens when the game starts at 7 p.m. Lambeau’s underground heating system will keep the turf from freezing. Below the surface, a network of plastic pipes containing antifreeze, covered by a foot of sand, make the field of natural grass and artificial fibers playable.

The entire system is monitored by temperature sensors in the field. The grounds crew uses a central control system to make adjustments if necessary. The system is designed to keep the turf at 55 degrees when the temperature dips to zero.