The Fujita Scale (also known as the Fujita-Pearson Scale) was not an accurate way of judging the damage a tornado can do. The Fujita Scale also had the description of the damage a certain tornado can do. Some of the times size doesn't matter, a puny weak tornado might be an F4, and a gigantic one might be an F0. The Fujita Scale isn't the only way to look at tornadoes. A tornado might be small at first and when it grows to an F5 it destroys everything. Since every other natural disaster had a scale Professor Fujita made a scale for the tornadoes.