SNOWFLAKES AND GLACIERS. “In regular ice, like you have in your freezer — hexagonal type 1, the formation of water molecules is not as open as in snow. It’s more tightly packed, as if you folded a flat hexagon in a weird way. And joined those together in a tighter formation. This structure is more dense and stronger than a snowflake structure.”
http://www.dailykos.com/story/2009/11/15/804812/-