As an architect, this has been my consistent advice for all people living within tornado areas. Sure underground construction costs a few thousand more than most crappy track houses, but it is worth it when you know that having a normal house makes you an easy target for the common natural disasters that occur in that area. Government (State or Federal) should get with it, and supply financial incentives to get most homes underground now! There is no reason to wait. If you want to keep your house and most things in your house safe, you need an underground house; not just a separate storm shelter or basement.
I would never live in an area that has tornadoes without living in an underground house, if I had any money or respect for life at all.
– Drogo Empedocles