That's what it looks like, yes. [The warning's been given, so she has no problem moving on to other topics.]

In a word, power. Legendary Pokemon are so absurdly strong that they can cause phenomena the likes of which I've never seen. Some of them can actually twist the weather around them just by being there, and those aren't even the strongest ones. The problem is that we don't really know much about any of them. They're elusive, some of them are probably one of a kind, and several of them don't even seem to live in this region of the world.