Research Team Visits Florida to Test New Tornado Rating Scale

Written by Cory Chandler

A year after the National Weather Service implemented a new rating scale to more accurately measure tornado intensity, Texas Tech University wind researchers are in tornado-ravaged portions of Florida this week to study how well the new scale worked.

The system, called the Enhanced Fujita Scale, will continue to rate tornadoes from zero to five, but should provide more accurate ranges in wind speed. It was developed in part by Texas Tech’s Wind Science and Research Center.

Weather Service field agents were trained over the past year to assess structural damage and then determine wind speeds and tornado ratings based on the new scale. The system was implemented this month just as a string of tornados hit Florida Friday, killing 20 people.

Larry Tanner, a civil engineering research associate, is now leading efforts to document structures damaged by the tornados – including mobile homes and recently built houses with in-home shelters – and measure how well the new system worked.

The original F Scale was developed in 1971 by the late University of Chicago professor Dr. T. Theodore Fujita to rate tornadoes and estimate associated wind speed based on the damage they cause. The new EF scale refines and improves the original scale. Limitations of the F Scale have led to inconsistent ratings, including possible overestimates of wind speeds.

Kishor Mehta and Jim McDonald of Texas Tech led a group representing Fujita Scale users – including nationally renowned meteorologists and wind engineers – that began working to revise the scale in 2001. The wind speed ratings were revised based on based on 30 years of damage assessment data recorded by Texas Tech from tornado sites across the nation.

CONTACT:

Larry Tanner, research associate, Department of Civil Engineering and Wind Science and Engineering Research Center, Texas Tech University, at (806) 543-4957, or larry.tanner@ttu.edu.
Carol Ann Stanley, coordinator, Wind Science and Engineering Research Center, Texas Tech University, (806) 742-3479, ext. 339, or carolann.stanley@ttu.edu.