Literally, in order for a vortex to be classified as a tornado, it must be in contact with the ground and the cloud base. Weather scientists haven't found it so simple in practice, however, to classify and define tornadoes (per this essay by Doswell).
Bikini Island, 2015. Credit: Emlyn Hughes. (Phys.org)âA team of researchers from Columbia University in New York has found that all of the Marshall Islands involved in nuclear tests by the U.S. are now habitable, except for Bikini Atoll.
The Bikini Atoll Survey Operation Crossroads, 1946-47. For some reason I do not fear the Atom Bomb era that is with the world. There are and will be I am confident, still enough good men and women in this world to control properly the various advancements of men.