Tweaking a twister
A tornado that's 500 meters in diameter looks a lot more ominous than the
average twister, which is "only" 150 meters across. All other things being
equal, larger tornadoes are more damaging, but size is not related to wind
speed. Instead, wind speed increases along with the difference between
atmospheric pressure inside the funnel, and the pressure outside it (the core
pressure difference). The larger the 
core pressure difference, the faster the
winds. But at a given wind speed, a larger tornado will do more total damage
because it will hit more objects. The Fujita scale estimates tornado damage.
Applet and illustrations copyright (C) 2003 Tom Whittaker, S.V. Medaris, and Steve Ackerman. The Motion-W® and Bucky Badger® logos are trademarks of the University of Wisconsin-Madison.
More, much more about tornadoes.
