That just shows all the areas that could be flooded, combining all the potential landfalls, right? I wish there were a graphic showing the areas that would flood for one particular path, so we could get an idea of how bad it could be in the vicinity of the storm. Some friends of mine have a house near La Porte that sits about 5 to 10 feet above sea level, right on the bay.
If you missed this link I posted earlier, here it is again. This should tell you plenty.
http://images.spaceref.com/news/2005/JSC.Hurr.Sim.pitch.ppt
Download a program called Global Mapper and you can do just that. Problem is, to get high res imagery you have to download one elevation model for each USGS quad, which only cover 7.5 miles by 7.5 miles. Then you have to get the roadmaps to overlay them too.
I have medium res elevation models for the whole earth on a server here and can do quick and dirty surge projections, but the fastest method of all is to use a mapping program like Topo USA from DeLorme and just plot the forecast track, then move the cursor around to the right of landfall while watching the elevation figures for the cursor's current position.