I'm buying a house in a neighborhood that fronts on the Maumee River in Indiana. I checked the address in http://www.floodsmart.gov/floodsmart/ and OMG it turned out to be high risk. I was crushed.
Anyway, I checked with our local planning office and I took a short list of addresses of nearby homes.
Turns out floodsmart will show you as high-risk (requiring flood insurance for a mortgage) if the flood plain touches any boundary of your property. Banks use a site plan/survey; therefore if the footprint of your building is an appropriate distance from the flood plain they WON'T insist on flood insurance.
Just thought I better post this here in case anybody (like me) is concerned about what high-risk means from the FEMA site. Your local planning office or recorder's office has detailed floodplain map overlays that will give you the real data you need.