I'm going with your comment from chapter 11. They aren't perfect, mistakes happen, and having perfect control in the big picture of what's happening is difficult. Yeah, there was someone working against them, but it's unknown if that was the case each time they failed. With all the variabilities in play when they made their first attempt, even without another Elemental countering their work, the uncontrolled hail storm might have still hit. I'm onto you though. You're trying to get me to write something about that and totally trash their abilities in a way that without a doubt it was their fault. lol. Hmm, this could be fun.