Skip to main content
All About Weather

Meet the man who defined tornado intensity

tornado over field

Mississippi and Alabama were recently hammered with severe storms and large-scale tornadoes. The damage that large high-speed tornadoes can cause is phenomenal and life-threatening.

Many have heard of the “F-Scale” or “EF-Scale” of tornado intensity. The F stands for Fujita, last name of the scientist that developed the scale.

Dr. Tetsuya Theodore “Ted” Fujita developed this scale while serving as a professor at the University of Chicago. His development of this scale, as well as his theories on tornadoes and severe storms, greatly expanded our knowledge of these events and has saved thousands of lives as a result. His professional career is one of perseverance, meticulous attention to detail, fascination of storms, and observation of damage caused by natural and unnatural events.

What is the F-scale?

In 1971, after observing tornado damage for several decades, Fujita developed a scale of tornado intensity that could be used to determine wind speed by the damage caused. In 2007, the scale was enhanced and changed in name to the EF-Scale

By observing tornado paths and the shape of debris left in the path, Fujita was the first scientist to determine that large tornadoes typically have multiple funnels rotating around a central tornado.

It started with an atomic bomb

Tutsuya Fujita was an engineering student in Japan in the early 1940s. After the second atomic bomb hit Nagasaki, he studied the blast wreckage. His examination revealed a circular blast pattern radiating from a central point, with trees right in the middle still standing. He calculated how far off the ground the bomb was at the time of detonation. Later, as a weather researcher, he theorized about downdrafts and microbursts, information that guided airports in the installation of ground-based radar to warn pilots of dangerous downdrafts.

Using aerial photos and interviews from participants of areas hit by tornados, Fujita theorized how tornados begin, change in size, and dissipate. He coined the term "wall cloud," a low-hanging rotating cloud. 

Where did “Ted” come from?

Upon receiving his American citizenship, Fujita changed his name, adding Theodore as a middle name which was shortened to Ted by media and friends. 

You can watch Mr. Tornado, an American Experience by PBS.


ABOUT THE BLOG: All About Weather is a blog by Duane Friend that explores the environment, climate, and weather topics for Illinois. Get in-depth information about things your weather app doesn't cover from summer droughts to shifting weather patterns. Never miss a new post! Sign up for our email list.

MEET THE AUTHOR: Duane Friend is an energy and environmental stewardship educator with University of Illinois Extension, serving the organization in many roles since 1993. Duane provides information and educational programs to adult and youth audiences in the areas of soil quality, weather and climate, energy conservation, and disaster preparedness. These programs provide practical solutions for families, farms, and communities.  He assists families in creating a household emergency plan, farmers with the implementation of soil management and conservation practices, and local government officials and business owners with energy conservation techniques.