Here are the rules:
-Particles should be capped to 1000. 1000 is huge anyway, and it also makes it so people understand bigger isn't better.
-An SFX isn't only particles. You can use geometry, just don't make it an entire unit with attack and spell anims.
-Also, the SFX shouldn't be any bigger than a yellow grid square in the WE (512 by 512).
-Ingame textures only.
-Feel free to base yourself on an already made Blizzard Effect, but the model must be considerably different from the original.
-You need at least 2 effects in your pack.
Filesize can't possibly be a problem. Particle effects range from 1 to 20 KBs, but it can get slightly bigger with geometry.
And Elements theme could be better than ice/snow, and this includes the "Dark" and "Light" elements.
As for rewards, I'll let the mods decide...