Or, you can check this FEMA site: http://www.fema.gov/hazard/flood/info.shtm
What is National Flood Insurance Program?http://www.floodsmart.gov/floodsmart/pages/about/nfip_overview.jsp
And quite frankly, if you observed the "homes are up on stilts", then there is a very high likelihood the homeowners are expecting/anticipating flood in the areas. For example, in Hawaii on the island of Oahu - the North Shore, a lot of homes there are built on stilts because they expect the large waves which come annually in December.
Unless, did you observed any beautiful mountains surrounding the area? May be the home are on stilts for the views?