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.
Las Vegas Museum: Historic Nevada Site. Before the Nevada Test Site, the United States performed nuclear tests in the Marshall Islandsâ Bikini Atoll. This was located 4,600 miles from the mainland of the United States. The Guardian reports that the nuclear tests done more than 60 years ago made the islands unsuitable for living even to this day.