Lately I've been having the urge to suggest my mother-in-law moved to Kansas because she deathly scared of tornadoes.
Why would you intentionally try to hurt her like that?
I have a very terrible relationship with her.
Whatever beef you have with your mother in law, that is no excuse for trying to frighten her into leaving. If you cannot deal with her anymore, ask another family member to take care of her.
Fuck off and stop acting like a child yourself. Next time something comes to mind don't fucking say it. Kansas is a great place for families.
Based on what you said it's not, you're intentionally trying to cause harm to your mother-in-law. Like I said, if you don't want to take care of her you need to talk with family to see if they could take her in.