Reassessing the Enhanced Fujita Tornado Scale

February 2, 2014 · 0 comments

It’s been more than 40 years since Ted Fujita introduced his renowned Tornado Damage Scale – the Fujita Scale. And nearly a decade has passed since top tornado scientists first collaborated with structural engineers to create the Enhanced Fujita (EF) Scale for rating tornado winds more accurately based on advances in our understanding of the variety of damage they inflict. Now, an effort is underway to tweak the EF Scale further – and the National Weather Service is looking for input from AMS meeting attendees this week.

The effort stems from the observations and analysis of recent violent tornado events: the massive tornado outbreak across the South in April 2011; the violent (EF5) Joplin, Missouri tornado of May 2011; and the Newcastle-Moore, Oklahoma EF5 tornado of May 2013. Survey teams were able to use more than two dozen “damage indicators,” such as wood-frame homes, strip malls, and schools—each further categorized by multiple “degrees of damage”—to gauge tornadic winds. But questions and even discrepancies arose among the survey teams as they scoured the wreckage of entire neighborhoods.

Oral and poster presentations throughout this week at the AMS Annual Meeting in Atlanta share information about the damage surveys, findings from reports such as the National Institute of Standards and Technology (NIST) technical investigation of the Joplin tornado and FEMA’s Mitigation Assessment Team Report on the Spring 2011 tornadoes, as well as thoughts for improving the EF-scale:

All of these represent on-going thinking about the EF Scale and how to refine it.

If you’d like to get involved, NWS is hosting an open discussion of the EF Scale to acquire feedback on its strengths and deficiencies. Space is limited so sign up today.