HUNTSVILLE, AL -- After the Nov. 15, 1989, tornado devastated part of south Huntsville, a member of Dr. Theodore Fujita's research team came to town to collect data on the storm's strength and path. Fujita's scale, also known as the F-scale, determined that an F4 tornado had ripped through the area around Airport Road and Jones Valley.
Today, researchers at the National Weather Service's Huntsville office are using new technology to get even more details about the damage the tornado caused.
Using information collected through aerial photography and included in a geographic information service (GIS) database, researchers can get a better understanding of the storm's power.
"We can get a handle on what happened in the past and look at the kind of damage that can occur, and look at, based on new development, what would the damage be (with future storms)," said Mike Coyne, meteorologist in charge at the NWS office. "When you go a long period of time without a tornado, a degree of complacency settles in. By doing research like this, you hope to spur more interest in the preparedness types of things."
Dr. Theodore Fujita's hope when he developed the scale bearing his name was to create estimates of tornado intensity based on damage patterns. The original Fujita scale contained 6 categories of storms ranging from F0 to F5, based on observed damage and estimated wind gust speeds.
An enhanced F-scale adopted in 2007 takes into account the age of buildings, which often determines the strength of a structure because of changes in building codes, said David Nadler, meteorologist for the NWS Huntsville office. The enhanced scale also looks at damage done to other structures, such as cell phone towers and power lines.
"That's how we're able to determine the strength of tornadoes," Nadler said. "When you get up to wind speeds of an F5, which is over 200 miles per hour, there's no instrument that can measure that."
Today is the 20th anniversary of a tornado that ripped through Huntsville, killing 21 and injuring 463.