I saw a show on the history channel about the old west. The trappers would cache a lot of their supplies and furs. The basic idea was to dig a hole fill it with stuff you wanted later and then cover it (but don't forget where it was). They would come out of the mountains open the cache, take what they needed, possibly store some furs, and then relocate it.

Regarding a hidey hole. I was a big Hogan's Heroes fan, so I've always dreamed of an underground hidey hole under my house. The general idea would be an entryway via the basement that was adequately concealed. My idea would be not to evacuate, but rather "appear" to vacate my home and actually be living underneath it. I also like the challenge of attempting to build it without letting the neighbors know what is going on. Unless there is a cave-in, and they find my corpse. I could become a monologue joke on Letterman.