[While Tohru doesn't understand how it's possible, this much she can explain.]

When I suddenly came to here, some people showed me to a place called the welcome center. Strange things kept happening around me, too!

[It had really surprised her!]

It's like a type of magic that's tied to your emotions. So if you were excited or happy, the flowers might bloom. If you were angry, the area around you could become hot! It's the same with the clouds... [Because she must be scared and upset right now.]