currently rated F5 by official sources. Many tornadoes officially rated F4/EF4 or equivalent have been disputed and described as actual F5/EF5/T10+ or equivalent tornadoes, and vice versa; since structures are completely destroyed in both cases, distinguishing between an EF4 tornado and an EF5 tornado is often very difficult. Additionally, because tornado ratings are damage-based, many tornadoes capable of causing F5/EF5/T10+ damage, such as those that move through rural areas, may receive lower ratings because their strongest winds do not strike any suitable damage indicators. List of events The tornadoes on this list have been formally rated F5 by an official government source. Unless otherwise noted, the source of the F5 rating is the U.S. National Weather Service (NWS), as shown in the archives of the Storm Prediction Center (SPC) and National Climatic Data Center (NCDC). Prior to 1950, assessments of F5 tornadoes are based primarily on the work of Thomas P. Grazulis. The NCDC has accepted 38 of his F5 classifications of tornadoes occurring between 1880 and 1950. In addition to the accepted ones, Grazulis rated a further 25 during the same period which were not accepted. From 1950 to 1970, tornadoes were assessed retrospectively, primarily using information recorded in government databases, as well as newspaper photographs and eyewitness accounts. Beginning in 1971, tornadoes were rated by the NWS using on-site damage surveys. Grazulis' work has identified 16 additional F5 tornadoes between 1950 and 1995, with four later being accepted by the NCDC. As of February 1, 2007, tornadoes in the United States are rated using the Enhanced Fujita Scale, which replaced the Fujita scale in order to more accurately correlate tornadic intensity with damage indicators and to augment and refine damage descriptors. No earlier tornadoes will be reclassified on the Enhanced Fujita scale, and no new tornadoes in the United States will be rated on the original Fujita scale. France and Canada also adopted the EF-Scale in subsequent years. Since the creation of the International Fujita scale in 2018, no tornadoes have been rated IF5. Official F5/EF5/T10+ tornadoes Worldwide, a total of 67 tornadoes have been officially rated F5/EF5: 59 in the United States, two each in France and Germany, and one each in Argentina, Australia, Canada, and Italy. Of the 59 tornadoes in the United States, 50 are officially rated F5 on the original Fujita scale (with dates of occurrence between May 11, 1953, and May 3, 1999),