Violent Tornadoes 1900-2010

With help from the SPC database and Significant Tornadoes by Tom Grazulis, I have plotted the tracks of F4/F5 tornadoes since 1900.  Ratings from 1900-1949 are from Grazulis with ratings from 1950-2010 courtesy of the NWS.  Post 1950 ratings between Grazulis/NWS agreed in most instances with few discrepancies (which are not shown below).

It is important to keep in mind that the Fujita scale wasn't developed until the 1970's.  Thus, any tornado that occurred prior to then was rated retroactively based on damage photos and descriptions.  The lack of on-site damage surveys for older tornadoes means that the ratings are subject to substantial error and may or may not represent what actually occurred.  Additionally, a number of these tornadoes crossed state boundaries and may have done the violent damage in another state, but they are counted as Indiana hits for the purpose of this post.

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