This map, published by Tetsuya Theodore “Ted” Fujita in 1975, shows the Super Outbreak of tornadoes that took place in the United States between 3 and 4 April 1974.
The Super Outbreak, to which Fujita's map refers, was the first recorded event in history in which more than 100 tornadoes were strung together in a single outbreak, with a total of 148 tornadoes in just two days, all concentrated in 13 states from Alabama to Michigan. At one point, as many as 15 tornadoes were active simultaneously, resulting in more than 300 deaths.
On the map, the author numbers the 148 tornadoes in a table on the right, and then represents them with a red line representing their path. The lines are also accompanied by numbers from 0 to 5 indicating the intensity of the tornado at each point along its path. Seven of them reached maximum intensity at some point.
A peculiarity of this work is that Fujita did not produce it from his office, but travelled all over the affected areas for months in order to base his depiction of the event on the evidence. All this work helped Fujita to refine the scale that measures the intensity of tornadoes, the Fujita-Pearson scale, which is still used today.
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