Study: Tornadoes deadlier during night

Knowing that severe weather threatens the area during overnight hours puts Mike Melton on edge.

As the director of the Colbert County Emergency Management Agency, he and others in his department will be the first to respond to reports of tornadoes and the damage they leave in their wake.

"It's just hard to tell what's going on," he said. "And, if we get lucky, we might get a split second flash from lightning to tell us a little more about the storm's direction."

A new study by Northern Illinois University scientists, however, gets to the root of Melton's stress. Their research underscores the danger of nighttime tornadoes and suggests that warning systems that have led to an overall decline in tornado death rates might not be adequate for overnight events, which occur most frequently in the mid-South region of the United States.

Walker Askley, a meteorologist and geography professor at NIU, said these findings are a concern because in the past 100 years the tornado death rate has steadily declined in large part because of sophisticated forecasting technology. The nighttime death rate for the same period of time has not declined as steadily as the rate for daytime tornadoes.

"The proportion of nocturnal fatalities and killer tornado events has increased during the last half century," Ashley said. "Unfortunately, this nocturnal fatality rate appears to be a major factor for the stalled decline in national tornado-related tallies during the past few decades."

The most dangerous window of time for a tornado, according to the study findings, is the period from midnight to sunrise. Tornadoes during this time are 2.5 times as likely to kill as those occurring during the daytime hours.

The study, which was published in the October issue of the American Meteorological Society's journal, Weather and Forecasting, also found that from 1950 to 2007, 27 percent of tornadoes in the U.S. were nocturnal, yet 39 percent of tornado fatalities and 42 percent of killer tornadoes happened at night.

Ashley said there are several reasons the death rate is likely to rise, among them population growth and development patterns, which include urban sprawl.

In the Southeast, there are two primary severe weather seasons. The first takes place from March through May, and the second is in November.

Although the Great Plains, which is known as "tornado alley," experiences more tornadoes than any other region of the U.S., most tornado fatalities occur in the mid-South, including Alabama, Arkansas, Mississippi and Tennessee.

Spencer Denton, a meteorologist at WHNT-TV Channel 19 in Huntsville, said recent tornadoes, including the one that ripped through downtown Nashville in 1998, prove that no area is immune from these kinds of events. Despite the damage done to structures, however, he said deaths are kept to a minimum thanks to technology, specifically weather radios.

Warning sirens, a sound many in the area have become familiar with, aren't as reliable, especially during the overnight hours, he said.

"With warning sirens, there is a big flaw," he said. "If you live right near one, you will hear it inside your home, but, if you live a certain distance from it, especially if you're asleep or if the TV is on, you're not likely to hear it. Even during the day, there's a similar problem. With weather radios that are battery-powered, if the electricity is out, you know something is coming, you get sufficient warning, and you can take advantage of that to get to a safe place."

Denton said many meteorologists have endorsed weather radios and WHNT has adopted it as a cause to get the technology in the hands of underprivileged homeowners in an attempt to save lives and to encourage people to have a plan of action during severe weather events.

"The time to have your plan is not as the sirens are going off," he said. "You need to know what to do during a tornado long before you know one is coming."

The key to having them work, though, is to have them programmed for the type of information an individual wants, said George Grabryan, director of the Lauderdale County Emergency Management Agency.

"The technology on them has gotten so much better," he said. "You used to get all the weather warnings, but now there is specific coding for certain events you want to be notified about, including tornadoes and winter weather advisories. Smart phones that the younger population are more into can serve as alert devices, too."

Grabryan said urban sprawl is becoming more of an issue in the Shoals, and, as a result, he said his department is reaching out to those parts of the county to install more warning sirens. The reality is, however, that there's no way to predict when and where a tornado will hit.

"Wherever you are, if a tornado is going to cross your path, it will cross your path," he said. "The likelihood of surviving it goes back to people heeding the warnings and being informed."

Michelle Rupe Eubanks can be reached at 740-5745 or michelle.eubanks@TimesDaily.com.