On New Year’s Day, the NHL held another edition of their “Winter Classic”, an outdoor hockey game put on in a baseball or football venue. This year, the game was so cold they had to heat the ice.

The NHL explains why: “When the air temperature is above the optimum ice temperature, the glycol and aluminum pans transfer heat away from the ice. But when the air temperature is below the optimum ice temperature, it transfers heat to the ice,”

And the solution: “The NHL has used a custom-made inline heater before to warm the glycol in the pipes on the way to the floor, but here it will use two inline heaters for the first time, one at the refrigeration truck and another in the outfield. The crew can calibrate the temperature to a half-degree.”

It’s an impressive setup, if more than a little ridiculous.