Tornado — Ratings

Developed by Dr. Ted Fujita in 1971, this was the first systematic method for rating tornadoes based on damage. It used an F0 to F5 scale to estimate wind speeds.

National Weather Service (NWS) survey teams deployed immediately after a major event follow strict procedures to assign an official rating:

Peeled shingles off roofs; broken tree branches; damage to signs. EF1 86–110 mph

Tornado intensity assessment has evolved significantly from subjective damage descriptions to standardized engineering-based scales. This paper examines the history, application, and inherent limitations of tornado rating systems, focusing primarily on the Fujita Scale (F-scale) and its successor, the Enhanced Fujita Scale (EF-scale). While the EF-scale represents a substantial improvement through the incorporation of Damage Indicators (DIs) and Degrees of Damage (DoD), this analysis concludes that tornado ratings remain a proxy for intensity rather than a direct measurement. Challenges such as the availability of robust structures, rating inconsistencies, and the influence of non-meteorological factors continue to affect the reliability of the climatological tornado record.

Roofs torn completely off well-built homes; large trees snapped. EF3 136–165 mph

By the early 2000s, wind engineers and meteorologists realized the system needed an overhaul. In 2007, the United States implemented the .

Well-built homes swept completely off foundations; structural steel deformed. How Forensic Meteorological Surveys Work