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.
Bikini Island natives want to emigrate to USA. Displaced residents of Bikini Atoll, relocated to the Republic of the Marshall Islands in the late 1940s because of U.S. nuclear weapons tests, want the option of leaving without losing millions of dollars in U.S. aid.