Since tornado records officially began in 1950, meteorologists have used the Enhanced Fujita Scale (based on the initial Fujita Scale, developed by a University of Chicago scientist, Dr. Ted Fujita, in 1971) to take stock of how severe tornadoes are. Tornadoes are rated on a scale from EF0 to EF5, with EF5/F5 as the most dangerous and the most rare. They usually cause severe devastation in their communities, leading to deaths, injuries, and severe property damage in virtually all cases.
2019 marks six years since the last EF5 tornado in the U.S., with the last one taking place on May 20, 2013, in the town of Moore, Oklahoma.
A six-year run without an EF5/F5 tornado in the U.S. makes this the second-longest streak in recorded history, in terms of Enhanced Fujita Scale records, without a severely catastrophic tornado.
The longest streak so far? Eight years, stretching from May 3, 1999, when an EF5 tornado once again hit Moore and Bridge Creek, Oklahoma, until May 4, 2007, when another catastrophic tornado hit Greensburg, Kansas. Oklahoma is historically the site of many of the country’s harshest tornadoes.
While EF5/F5 tornadoes are rare, they are not unheard of. Since tornado severity first was recorded in 1950, the NOAA Storm Prediction Center and the National Weather Service say that 59 EF5/F5 tornadoes have hit the U.S.
Most commonly, they have hit Oklahoma and Alabama, with seven of these severe tornadoes each, with Iowa, Kansas, and Texas following closely behind. 18 states overall have been hit with EF5/F5 tornadoes since 1950, stretching from North Dakota on the northern side to the eastern U.S. in Ohio.
Although the average number of “5-rated” tornadoes is less than one per year, 1974 was a record year for these devastating incidents. From April 3 to April 4 that year, a shocking total of seven 5-rated tornadoes spun out of control in less than 24 hours. These periods are known as “super outbreaks,” and there was another in 2011, when April 27’s outbreak brought six tornadoes across the end of April into May in Oklahoma, Missouri, Alabama, and Mississippi.