I'm hoping the snowball has the same hooks as the egg something lightweight so its not having to spam height with the BukkitScheduler and I hope that is pure history because the key is lightweight. So what I would like create just a simple plugin where you can use snowballs to place snow patch. Now i forget but if snow patches causes more then 1 snow ball to spawn it might be a good idea then to create a patch to only drop 1 at a time.
That was quite a fun exercise. It uses the projectilehit event to get snowball hits, so it shouldn't be heavy or anything. Checks whether the hit block is air and the block underneath is solid, then creates snow. Source included, have fun. http://www.filedropper.com/snowmaker