A tornado family is a series of tornadoes spawned by the same supercell.[1] These families form a line of successive or parallel tornado paths and can cover a short span or a vast distance. Tornado families are sometimes mistaken as a single continuous tornado, especially prior to the 1970s. Sometimes the tornado tracks can overlap and expert analysis is necessary to determine whether or not damage was created by a family or a single tornado. In some cases, different tornadoes of a tornado family merge, making discerning whether an event was continuous or not even more difficult.
Some tornado damage remains a mystery even today due to a lack of evidence. The Tri-State Tornado was one such tornado. It could either have been the longest single tornado recorded, or a family of tornadoes. New re-analyses suggests that it was one continuous tornado[2], however, many other very long track tornado events were later found to be tornado families, notably the Woodward, Oklahoma tornado family of April 1947 and the Charleston-Mattoon, Illinois tornado family of May 1917.
Tornado families can be a result of satellite tornadoes, cyclic tornadogenesis, or some combination of both.