Published on 04/12/07

Tornado time?

By Sharon Omahen
University of Georgia

Georgians may think of spring as the beginning of tornado season, but University of Georgia experts say tornadoes can occur almost year-round.

"Tornadoes can happen any time of year, any time of day," said Pam Knox, Georgia's assistant state climatologist and a researcher with the UGA College of Agricultural and Environmental Sciences. "It's true, spring to early summer seems to be the time of year we think about tornadoes. But Georgia has had them all year."

Tornadoes typically occur when "the humidity is high, the winds change with height and there's sunshine," she said. They most often form in front of a "push of energy" like a cold front.

Too cold for twisters

It can be too cold for a tornado, Knox said.

"They won't happen if the temperature's 32 degrees or lower," Knox said. "That said, there are also isolated tornadoes that happen outside these atmospheric conditions. Many form in the right front quadrant of a hurricane like before (Hurricane) Ivan in Georgia on Sept. 15-16, 2004."

Remembering such dates is part of Knox's job as assistant to Georgia state climatologist David Stooksbury. It's also part of her nature.

"Most meteorologists get hooked on weather at an early age," she said. "I was hooked in the third grade when a tornado hit two blocks from our house in Michigan. It took the middle of a church and left the two ends standing."

Despite this experience, Knox isn't scared of tornadoes, because she understands how they form. She also knows the math.

Slim odds

"Statistically, the odds of a tornado hitting a particular point are like 1 in 5,000 or so," she said.

Tornadoes are part of what Knox calls "a whole suite of things that can happen in a thunderstorm."

The average tornado follows a well-defined path of about 10 miles and usually touches ground for just one mile. "Sometimes a tornado will skip along the ground, and sometimes it never hits the ground," she said. "When that happens, it's just a funnel cloud."

Tornado warnings may seem to last forever, but Knox says an average tornado lasts about 15 minutes.

You can't see them coming

If you live in a state like Colorado, you may be able to see a tornado coming from 20 miles away, Knox said. Georgians, unfortunately, don't have that luxury.

"Sometimes tornadoes are wrapped in rain so you don't see them," she said. "And we have lots of hills in the Southeast, so you can't see tornadoes coming. That's why most tornado photographs are taken in the plains of Oklahoma or Kansas."

Many tornado survivors liken the sound of a tornado to that of a moving freight train or a swarm of angry bees. But don't rely on sound or sight during a tornado warning, Knox said. Instead, rely on weather reports from the National Weather Service.

"A weather radio is one of the best purchases you can make for your family's safety during any weather emergency," she said.

Don't trust the movies

Knox also warns people to remember that tornado movies are often more fictional than factual.

"The movie 'Twister' significantly increased the number of students majoring in meteorology," she said. "Unfortunately, it wasn't very true to life. It usually takes 10 tracking trips to see one tornado. We meteorologists have to suspend our scientific beliefs when we watch tornado movies."

Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.