LINKS:

1.   Electrogravidynamic Concept of Tornadoes
    by A.N.Dmitriev, V.L.Dyatlov, V.I.Merculov;

2.   Wikipedia;


3.   http://www.teara.govt.nz/en/weather/6;


4. http://wiki.answers.com/Q/How_powerful_are_tornadoes