If this wasn't so story flimsy and repetitive, this would be good. It's like they wanted to get to the fun parts without solidifying the plot. This is all "look at my cute little sisters that are in love with me!" Which is also... yikes..
I think that the problem itself is that Tina is too much powerful and a little basic spell is the one capable of generating snowstorms that is always seen . Just a gut felling