Haha, I'm probably partially to blame for the whole map being made of snow. The materials and textures for this are from a really,
really old map I made called "Arctic Mission", which was basically just Grasslands re-skinned to be made of snow (and to have snowmen). I recoloured all the textures so they would look icy, but I probably got a bit overzealous with it, since I basically just made everything ice.
That said, parts of antarctic are entirely made of ice, so it's not impossible.