Snowballs are formed when a player mines the surface. As the snow settles on dirt, or any other surface, it becomes another layer. It takes a short amount of time to mine it, and once mined a snowball will appear in your inventory. The snowball can be used as a weapon, but it will not cause any damage to enemies (except for Blaze's), it will simply knock them back. Combining 4 (four) snowballs will create a snow block.