Fujita tornado indeling
The fujita tornado intensity scale is used to rate the intensity of a tornado by examining the damage caused by the tornado after it has passed over a man-made structure
http://www.tornadoproject.com/fscale/fscale.htm
Tornado (VWKweb)
Website van de vereniging voor weerkunde en klimatologie. website over weer en klimaat in de hele wereld.
http://www.vwkweb.nl/index.html?http://www.vwkweb.nl/weerinfo/weerinfo_tornado.html