[Netz]

Where would you “feel” safer? Under the ground or above it when this kind of thing hits? Man's nature is to dig down to seek shelter or digs a “foxhole” or “hunkers down”, lays low, “hugs the Earth”, etc. No man made structure, at a reasonable cost protects man better than the Earth herself therefore...dig.

[GeronL]

Obviously above ground shelters are close to worthless when “this kind of thing” runs over you.

[eastforker]

BS. Iron and concrete would make a bunker no tornado could penetrate.