Recent storms have left path of destruction-Dense population, large number of trailers, increase tornado damage

They can level an entire neighborhood in a matter of seconds and carve a swath a mile wide leaving nothing behind but splintered debris, their most recent power felt April 11 when an estimated 60 homes were damaged in Warren County.

Tennessee serves as secondary tornado alley, ranking behind only the Midwest in the number of tornado strikes a year. While Tennessee can expect to see 16 tornadoes in an average year, every state has recorded at least one tornado. Even Yellowstone National Park, at an altitude of 10,000 feet, was hit with a tornado in 1987 with cleared a path of 24 miles.

The Tristate tornado of 1925 was the worst tornado on record, covering a path of 219 miles and killing 619 people.

Meteorologist say the Midsouth has seen a greater number of tornadoes in the last five years, part of a reoccurring pattern of increased tornadic activity which weather watchers have seen over the past century. Most experts agree the cycle should return to normal in the coming years, while some argue global warming could permanently impact a shifting of tornado alley to include the Midsouth.

Regardless, statistics show tornadoes in the Midsouth are deadlier than those in the Plain States due to a variety of reasons, including the fact the tornado season is longer here. Also many Tennessee twisters occur at night when people are sleeping. The Midsouth is more populous than the Midwest and has a greater number of trailer homes.

Most tornadoes are generated by severe thunderstorms, the type that are common in the Midsouth during March, April and May and to a lesser degree in November and December. Most tornadoes occur late in the afternoon or at night in Middle Tennessee, but the devastating storms have been known to strike any time of the day or during any season of the year, provided conditions are right.

This year two major strings of tornadoes have already hit Middle Tennessee, the first on Feb. 5 when 33 people were killed, most fatalities coming in Macon and Sumner counties to our north.

A tornado is a violently rotating column of air extending from the base of a thunderstorm. When the rotating column comes in contact with the ground, it is considered a tornado.

Tornadoes have an average wind speed of around 100 mph. However, the strongest recorded tornadoes have been known to pack winds of over 300 mph, the strongest tornado ever occurring in 1999 near Oklahoma City.

A tornado’s intensity is measured on the Fujita scale, a severity measuring formula developed by Dr. Tetsuya Fujita.

The weakest tornadoes are considered F1 twisters and pack winds of 73-112 mph. Although on the bottom line of the scale, the twisters still pack enough power to overturn mobile homes and rip off roofs.

A high-end F1 twister is what experts say inflicted a record amount of damage in Warren County less than two weeks ago when it hit Candlewood subdivision. An F1 is also the classification of the tornadoes of April 7, 2006 which killed three people when two separate twisters hit the north and south parts of Warren County.

The second classification, F2 tornadoes, pack winds of 113-157 mph and can cause considerable damage, uprooting trees and totally destroying mobile homes.

F3 tornadoes can cause severe damage as they pack winds of 158-206 mph, are able to overturn trains and knock over well-built homes. Many of the twisters which hit the Midstate in May 2007 were F3s.

An F4 twister, with winds of 207-260 mph, devastates anything in its path, leveling well-built homes and tossing cars great distances. An F4 twister hit the Barfield community of Rutherford County in 1997, damaging 147 homes and inflicting $4.7 million in damage.

Although rare, an F5 twister is the most devastating force in nature. With winds of 261-318 mph, an F5 can disintegrate well-built homes and carry debris for miles.

Given the massive force of tornadoes, the National Weather Service, in cooperation with the Tennessee Emergency Management Agency, strives to give the public early warning should conditions be right for one of the devastating storms.

When conditions are right for the formation of a tornado, a watch is issued. Watches usually include an area several thousand square miles in size.

When a tornado is indicated by Doppler radar, or a twister is sighted by a storm spotter, a tornado warning is issued. Warnings are issued in the specific area where a tornado is indicated.

Warnings for this area are usually broadcast by TV stations. The warnings are also normally announced by the local EMA which preempts local cable programming to broadcast the warning. Updated weather information can also be found on weather-band radio at frequency 162.475.

If you are in a warning area, experts say you should take immediate precautions.

If you are in a house when a tornado strikes, you should go to the basement or interior room, such as a bathroom or closet on the lowest floor of the structure. You should put as many walls between you and the outside as possible.

Mobile homes should be abandoned immediately and a more sturdy structure sought for cover.

Once you have taken cover, you should get under something sturdy such as a workbench or table. You should also avoid windows. Do not take time to open the windows because it will not make much difference to the structure. Instead, by attempting to open your windows, you could be subjecting yourself to an unneeded danger.

In large buildings such as schools, shopping centers, factories and hospitals, proceed to the pre-designated shelter area. Interior hallways and restrooms on the lowest floor are ideal. Avoid rooms that are large in area because they have weak roof supports.

If you are in a vehicle, experts say you should not try to outrun a tornado because of the fact winds from the storm could blow your car off the road while the twister is still a good distance away. Instead, look for more suitable shelter, such as under a bridge overpass, and abandon the vehicle as soon as safely possible.

In addition to taking proper precautions, the NWS advises you to keep abreast of updated weather information concerning severe storms either by TV, radio or weather-band radio.