‘EF’ Scale: What determines tornado strength

Because there’s no way to accurately prove the strength of tornadoes based on radar or by sight, Meteorologists must assess the damage left by a tornado to determine the strength. National Weather Service Meteorologists must accomplish this as quickly as possible before debris is cleared up and signs of damage are repaired.

The Fujita Scale was developed by the late Dr. Ted Fujita, who was the pioneer of tornado science at the University of Chicago in the 1970s and 1980s.