I don't think it's that strange. Orienteering maps use white to indicate "forest", because it's the thing you have the most of and therefore is of the least int

I don't think it's that strange. Orienteering maps use white to indicate "forest", because it's the thing you have the most of and therefore is of the least interest. As another commenter pointed out, the colour scheme helps the ice "pop out", especially the pockets of ice near land.