A tornado is a destructive weather phenomenon that occurred on some planets, such as Bajor and Earth. On Earth, most tornados took place in the USA between the months of April and June in an area known as "tornado alley". On Earth, tornadoes could be dissipated by weather modification networks. (TNG: "True Q")
Amanda Rogers' parents were executed by the Q Continuum in the form of a single tornado, which spontaneously appeared over their house in Topeka, Kansas, destroyed the house, and then disappeared. (TNG: "True Q")
In 2365, Theta VIII's atmosphere was found to contain large concentrations of ammonia among other gases that formed ammonia tornadoes. (TNG: "The Royale")
Yaderan folklore stated that Changelings could transform into tornadoes. In one story that Taya told Odo in 2370, the Great Minra tricked a Changeling by telling him tornadoes were easy to transform into. (DS9: "Shadowplay")
After the Reckoning began in 2374, the Bajoran city Tamulna was hit by a tornado. (DS9: "The Reckoning")
Tornadoes were sometimes used in a humorous way to describe destruction in a particular area. In 2370, Miles O'Brien joked that a tornado that no one on Deep Space 9 heard had damaged the science lab. (DS9: "The Alternate")