Turns out that is a dangerous urban legend promoted by a video shot by a TV crew in Kansas during 1991. Since then, people have attempted to hide under overpasses....with less than desirable consequences.
Flying debris is one of the most dangerous aspects of a tornado. Being under an overpass actually increases the odds of being hit by debris because:
- you are higher off the ground than you would be if you were lying a ditch....and therefore more likely to be hit by something
- wind speeds can increase due to the shape of the bridge itself
Parking under an overpass also creates a traffic jam for emergency vechicles and others fleeing the tornado.
Below is a collection of photos of storm damage. The majority consist of objects pierced by debris. The blue and white truck actually has part of a refrigerator in it. I threw the record in for fun... though I'm pretty sure that's a urban legend too.
What should you do? NOAA says park your car, find a ditch, and lay down in it. Oh...and if you are in a mobile home...your toast so you might as well go outside and find a ditch. Don't worry about opening windows in your house to equalize pressure. Odds are a flying 2x4 will do that for you.
Follow this link for more info on the freeway overpass myth.
