The Snow Farm was a building that harvested snow on Trenzalore. Since the planet only contained frozen bodies of water, the Snow Farm was the main source of water for further settlements.
Zontan once broke the Snow Farm control panel to create a blizzard that would build enough snow to activate an avalanche and destroy Christmas, but the Eleventh Doctor fixed the controls and prevented the avalanche. (PROSE: Let it Snow)
The Snow Farm was later used to manufacture salty snow that defeated the Mara. (PROSE: The Dreaming)