The fear of a wild, Escape from New York-type situation after a major natural disaster. With respect to Katrina, in particular, so much of what we saw or read about turned out to be fantasy and gossip. Some news outlets like the Times Picayune and LA Times had the integrity to admit that fact after some time had passed and more investigating had been done. That said, there were also some horrible things that happened after Katrina that most folks haven't heard much about so I'm not saying that nothing bad happened. Just not much of the senational stuff (Remember the piles of dead bodies stacked in the freezers at the Superdome? Or the heated firefight at one of the bridges between "looters" and police that turned out to be the police and private security contractors firing on each other?)

With so many videos from the Indonesian and Japanese tsunamis, I think most people are getting away from the impression that a tsunami is this towering wall of water that breaks and crashes down onto the beach. Tsunamis generally don't crest and break on shore. The water rises and just keeps pouring ashore.

That hiding up under a freeway overpass is the safest place to be when a tornado passes overhead. In fact, the overpass acts like a funnel and actually increases the wind speed under the overpass, making any flying debris that much more dangerous as flying missiles. Better to seek a ditch in open ground away from any vehicles or other large objects that may get blown on top of you.

And lastly, zombies!