I recently heard that the Fujita F-scale of tornado intensity goes up through F-12. Is that possible?
The Fujita Tornado Scale does technically distinguish 12 levels of wind intensity even though the maximum twister wind speeds have risen only to the F-5 category (261 to 318 mph). University of Chicago Professor Dr. Theodore Fujita developed the scale after investigating a Lubbock, Texas, tornado in 1970. F-0 intensity was for wind speeds of 40-70 mph and F-5 intensity tornadoes produce winds up to 318 mph. The F-Scale was revised in 2007 to lower wind speeds to more closely represent the wind speeds in tornadoes. An F-6 tornado is believed to be highly unlikely and such a twister’s damage might be indistinguishable from the catastrophic damage of an F-5. F-12 winds are at the speed of sound, 762 mph.