Spate of tornadoes disrupt South

Several waves of tornadoes churning across the Tennessee Valley over the past week have killed 40 people, wrenched apart half-million-dollar homes, and trapped hundreds of students as one twister bore down on a junior college near Gallatin, Tenn.

After several relatively quiet tornado seasons in the South, the more than 300 tornadoes that already occurred this year is unusually high. When a line of tornadoes swept across Tennessee on Friday, 12 people were killed as the state's mid-region had its deadliest week of weather since 1974.

Forty-two twisters were spotted across Tennessee, Alabama, Mississippi, Indiana, and Kentucky.

The storms have been strong, too: The debris-strewn scene from the Woodhaven neighborhood in a populous area just outside Gallatin took many tornado experts by surprise. Often the way deadly storms turn out has more to do with human readiness than nature's atmospheric fault-lines, experts say. "Tornadoes shift around just enough so that the society, the people, get relaxed," says meteorologist Tom Grazulis, director of the Tornado Project in St. Johnsbury, Vt.

Three major tornado-spawning fronts have moved across the area since late March. Higher than average water temperatures in the northern Gulf of Mexico may be to blame. Researchers, however are not sure if the warmer water is playing a role.

"These storms have been driven by the winds in the upper atmosphere and lower pressure systems coming off the Pacific and through the Rockies, falling into the Plains" where they meet heavy, warm air pressing up from Mississippi, says Shawn O'Neill, a National Weather Service meteorologist in Morristown, Tenn.

Friday's storms hit one of the state's many spreading suburbs. A junior college was badly damaged as 200 students huddled in a gym. Some students suffered minor injuries. About 30,000 homes lost power in the region, and 1,600 homes were damaged or destroyed in Warren and Sumner Counties. The most serious casualties occurred in the upscale Woodhaven neighborhood and at a mobile home park.

In northwest Alabama, strong winds and possible tornadoes tore trees out of the ground late Friday and into Saturday. Two people were seriously injured when trees hit their car in Hamilton, Ala. Residents in Haleyville, Ala., saw golf ball-size hail. And at least one prom was cancelled in Alabama Friday night because of the severe weather. "Tornado-like" storms also damaged structures north of Atlanta early Saturday morning. Storms continued to do damage to buildings all the way into South Carolina on Saturday.

On April 2, tornadoes killed 24 people in western Tennessee and four people in Missouri and Illinois. The storms damaged or destroyed nearly 1,000 homes.

Despite these recent storms and an increase in population in many parts of Tornado Alley - which covers the broad lowland areas of the Mississippi, Ohio, and lower Missouri River valleys, and the South - tornado deaths per year have been steadily dropping in the past 50 years and are now at 45, says Grazulis. The downward trend has been attributed to better construction standards and also improved forecasting and awareness.

The weather service began warning people on Wednesday of possible large tornadoes throughout central Tennessee.

Long-time resident Kay Scott found herself in her car (not the safest place to be when the tornado sirens are blaring) when the front moved in Friday afternoon.

"I was picking up my youngest child and they pulled all us parents into the school and put the school on lockdown," says Ms. Scott, a realtor in Gallatin. No one was hurt at a middle school in the town.