Jean Smith wrote:

There have been a number of studies detailing steps which must be taken
to improve hurricane resistance in residences. Coincidentally, most of
those steps also increase tornado resistance...things like actually
attaching the roof to the walls, and the walls to the foundation. 95%%
chance that this has not been done (adequately) to the structure in
which I am typing (or you are reading). There is always some caprice
involved in what gets demolished, and what's left standing; but
attention paid to those two factors, and a few others can increase the
resistance many fold. Most of them have been written into building
codes in coastal areas since Hurricane Andrew in 1992. Requiring them
in tornado-prone areas would not be out of reason.

This 'is' an extreme example, though.

jak