How does one counter mei ?

mei herself does weak damage which is 75 non-headshot delayed projectile. I guess most of you problems with mei are form her sneaking to you and the freezing you with the iceycle-headshot combo. To avoid that you need to know where she is and keep optimal distance from her. The best counters would be Reaper ( you can wrath fomr right before she freezes you) and simple good distance dps like soldier phara mcree.