Underground has always been the preferred choice for tornado sheltering in the Midwest, Sylvia, because the work wonderfully and are inexpensive.We design and build with an abundance of windows but you can buy or build hurricane shutters Build on a slope for water drainage away from the house and follow the advice in the books and videos as per mounding earth in a V above the uphill patio, using french drains, etc. You can also drain off on a sidehill patio. Start small and see what works for you. -- MO