Texas Tech Research Lays the Foundation for Safer Houses

Just days after the National Weather Service implemented a new rating scale developed in part by Texas Tech’s Wind Science and Research Center, our researchers visited tornado-ravaged portions of Florida to study how well the new scale worked.

Like the well-known Fujita Scale that it replaced, the Enhanced Fujita Scale continues to rate tornadoes from zero to five. However, it should more accurately measure tornado intensity. The new system rates building damage by category, meaning houses have a different set of criteria than other buildings, such as schools or mobile homes.

“It makes the design more consistent around the country,” Kishor Mehta, former director of Texas Tech’s Wind Science and Engineering Research Center, told the Associated Press when the system was adopted. “By getting so many damage indicators we will have so much more accuracy in assessing damage and accuracy in assessing wind speed.”

National 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, killing 20 people.

New Notes on an Old Scale

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

Mehta and Jim McDonald of Texas Tech led a group comprised of Fujita Scale users to revise the scale. Wind ratings were revised based on damage assessment data recorded by Texas Tech from tornado sites across the nation.

The National Weather Service adopted the Enhanced Fujita Scale in February 2006 but did not fully implement it until February of this year to allow for training.

In the News

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

Tanner’s research of approximately 400 manufactured homes damaged by a 2005 tornado that killed 22 people in Evansville, Ind., prompted new standards for mobile home installation in the region. He submitted a report of his findings to the National Institute of Standards and Technology.

He led a team of researchers from Texas Tech University’s Wind Science and Engineering Research Center in Florida to study debris and damage in the wake of tornados that killed 20 people.

Their work could lead to changes in construction standards and guidelines that could better safeguard families during wind events.

• Storm victims' homes were death traps, Sun-Sentinel and Orlando Sentinel
• A Twist To The Fujita Scale, Heartland News
• NOAA National Weather Service’s improved tornado rating system now operational, a press release issued by NOAA's National Weather Service
• Storms pass; danger remains, St. Petersburg Times
• Tougher anchoring rules: A life-or-death difference? Orlando Sentinel
• Tornado ratings get a fine-tuning, Star-Telegram
• New tornado ratings take effect, Myrtle Beach Online

Additional resources:

A Recommendation for an Enhanced Fujita Scale

National Oceanic & Atmospheric Administration

National Weather Service