For the math nerds amongst you, here are some details about the underlying game mechanics:
Every thrown snowball has a ~33.33% chance to completely miss its target and a ~16,66% chance for a guaranteed lucky hit, no matter how high your level is.
If none of these chances trigger (which means in 50% of all throws), the levels of both users will determine the outcome. Behind the scenes, an invisible die with X sides is rolled, where X is the sum of the levels of both users plus ten.
Example: If a level 16 user throws a snowball at a level 4 user, a die with 16 + 4 + 10, i.e. 30 possible results is rolled. 16 of those results lead to a hit, 4 of these results lead to the targed dodging and 10 results lead to you merely grazing the target.