So I think that at the moment yasuo's windwall does not block projectiles. I dont know if this just a bug with snowball fight in nexus blitz but currently on pbe yasuo windwall does not block any projectiles. If needed I can go record footage of his windwall not working and put it no this post, but for now people should just see for themselves in custom games.
Post your PBE bug reports here: something not functioning as intended? Store is broken? A champion's ability is not working? etc
Need help? Read our [bug reporting guide](http://community.pbe.leagueoflegends.com/c/bugs/CF5EEDC8FF5AC1A896F517E2C7AE4650C472807F-how-to-report-bugs-on-the-pbe).
Comments about things you don't like or suggestions for improvements go in Feature Feedback.