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.
Assuming that the plant on that little island above Bikini Bottom is a tropical palm tree, Bikini Bottom and thus SpongeBob live in the Pacific ocean, a warm tropical reigon. As seen in the Movie, David Hasselhoff travelled west to take our hero back to Bikini Bottom, and unless David was somehow in Spain, he was heading from North, South or Central America to Bikini Bottom.