re: The Walking Dead s4e3 "Isolated" (non-spoiler edition)

Brad for the most part mountains would be effective deterrants for herds unless they were specifically chasing something. I mean if the herds move somewhat randomly with a group intelligence (as they do in every type of Zombie fiction including gulp the comic and the show) that means unless they get an outside stimuli they wander around on a path of least resistance. Hundreds of miles of Cherokee national forest and the steep hills/mountains that separate and isolate Cades Cove and all of the Smokies from any population center means a herd blowing through Cades is almost impossible.