Took a moment to decide whether this was Fluttershy or an aged-up Scootaloo. After some debate, both of them could fit in here as potentially powerful pegasi whose potential is reluctantly shown, but terrible and final when it is manifest. ...and they're a lot more similar in colors than I realized before.
Suddenly a great storm appeared, forming a tornado of water, clouds, dust and splitters. The Horizon was filled with fog and dust as the Storm made its way through the land and took everypony and everything with it that was not righteous nor good of this Land.