"Cepheus has the power to control the crystal to an extent. It’s a bit like a living organism in that way, it can’t be manipulated at his every whim. A few weeks ago, he was able to accomplish the first surge. From what we know, it was strong enough to take off a few feet of coastline, but since then it’s weakened, probably a few inches at best since the first surge. With the whole crystal tonight, the power is going to be enough for a tidal wave, a tsunami. It will probably be over before we make it up there, but I thought you should know that once they perform the ritual, we're going to the surface with the fleet to take care of any muggles that are able to avoid the floods" Leander paused, gauging Draco’s reaction. He was staring stoically, no sign of emotion or surprise. 