What is the Fujita Scale (F Scale)?

The Fujita Scale (F Scale) is a classification system developed in 1971 by Dr. Tetsuya Fujita to estimate the wind speeds of tornadoes based on observed damage. It ranges from F0 (weakest) to F5 (strongest), with each category corresponding to increasing levels of destruction.

Originally, the Fujita Scale estimated wind speeds indirectly by examining the damage caused to buildings, trees, and infrastructure. However, because wind speeds were difficult to measure directly, the Enhanced Fujita Scale (EF Scale) replaced the original F Scale in 2007, refining damage indicators and wind speed estimates.

Fujita Scale Categories:

• F0 (40-72 mph) – Light damage: broken branches, shallow-rooted trees toppled.
• F1 (73-112 mph) – Moderate damage: mobile homes overturned, minor roof damage.
• F2 (113-157 mph) – Considerable damage: roofs torn off, large trees uprooted.
• F3 (158-206 mph) – Severe damage: walls destroyed, vehicles lifted off the ground.
• F4 (207-260 mph) – Devastating damage: houses leveled, cars thrown.
• F5 (261-318 mph) – Incredible damage: well-built homes swept away, severe structural deformation.

While the Enhanced Fujita Scale (EF Scale) has largely replaced the original Fujita Scale in the U.S., the term F Scale is still commonly used when referencing historical tornadoes and their classifications.