Friday Night's Tornadoes

By: Christy Henderson | News Channel 7
Published: April 13, 2009 | 0 Comments | Post a Comment

So far the National Weather Service has confirmed 6 tornadoes that touched down Friday night. Northeast Georgia and the Upstate had almost 2 1/2 hours of rotating storms in the area, and it was between 6:55pm and 9:17pm that the tornadoes touched down across the area.

Carnesville, GA, Townville in Anderson county, the city of Abbeville, Jonesville in Union county and the city of Greenwood had the misfortune of having to endure this severe weather. Most of the tornadoes have been classified as EF 1's on the Enhanced Fujita Scale.

The twister in Abbeville county was an EF 2 with maximum winds of 125 mph. Two tornadoes touched down in Greenwood, and even though the initial classification was for both to be rated EF 1 with max. winds of 110 mph, the NWS indicates that they may upgrade that to an EF 2 when they have more time to inspect pictures they took at the scene.

Apparently there were some large hardwood trees that were mowed down, so the strength of the Greenwood activity may be stronger that first thought. We'll learn more about all of the damage and surveys over the coming week or two.

So how do we figure out a tornado's strength? We use the Enhanced Fujita Scale. Unlike hurricanes, we don't fly planes into tornadoes to measure them while they're happening...Tornadoes are much smaller and more concentrated, and they don't last but for a few minutes in most cases. Hurricances can last for weeks. Because of this, we measure a tornado's strength AFTER it does the damage. Until February of 2007 we used the Fujita Scale - named after Dr. Ted Fujita - a meteorologist at the University of Chicago. He related wind damage to wind speed.

Engineers and meterologists developed what we call the Enhanced Fujita Scale to get a more accurate picture of how strong the tornado was. It has 28 different damage indicators that the survey crews inspect and rate, and takes construction into account as well as what was damaged. The same wind speed would cause much different damage to a mobile home than it would to a brick home, so this enhanced scale helps to take that into account.

The scale goes from F0 to F5 which ranges from 65 mph to over 200 mph 3-second wind gust.