Zoe is in rage and when she's in rage she roars loud like a big strong lion.
Her ultimate roar means that she is now, Winter Storm Zoe.
Winter Storm Zoe has 100x the strength of her powers and her ability to easily control all winter weather all over the continent. But beware, Winter Storm Zoe can also unleash powers from darkness and evil, however, as long as she remains her powers controllable, no evil spirits will be harmed.
So yeah, Winter Storm Zoe is almost like Black Suited Spiderman. If you guys don't know what I mean then definitely watch Spiderman 3.

Should've made her hair much longer like before, but you guys get the idea.

Oh and by the way I did mention earlier that Zoe carries her candy cane staff for special occasions.