Wrong Moves Can Be Deadly With Lightning, UF Experts Say

July 7, 1999

GAINESVILLE – With summer thunderstorms once again in full swing, University of Florida researchers are reminding those playing or working outdoors to be wary of the deadly lightning that comes with them.

Staying away from wide-open spaces is the best lighting defense, researchers say, but ducking under a large tree or in a small shelter not protected from lightning makes you part of the lightning rod.

“Lightning is attracted to the highest object in an area, and a tree that extends beyond the surrounding landscape can become the target of a strike,” said Martin Uman, director of UF’s Lightning Research Center. “Isolated golf course and picnic shelters that are not protected from lightning also are risky.”

Among those who make their living outdoors, farm and ranch workers are especially at risk, said Carol Lehtola, agricultural safety specialist for UF’s Institute of Food and Agricultural Sciences.

“We all know that golfing and other sports expose you to lightning, but most people don’t realize that farm and ranch workers are at high risk because they do much of their work outdoors far away from shelter,” Lehtola said.

In May, for instance, seven farm workers in Myakka City were injured when lightning struck the metal flatbed trailer they had crawled under for shelter from a storm.

“Too often, workers and their supervisors stay on the job until it starts raining and get back to work as soon as they can after a storm passes,” she said. “They don’t realize that lightning can strike them when thunderstorms are in the area but the sky above them is clear.”

All crews of farm workers should include at least one person who has training in cardio-pulmonary resuscitation, Lehtola said, and supervisors of agricultural workers should carry a weather radio so they can be alerted to storms in plenty of time.

Lightning danger begins with the first rumble of thunder and continues until 30 minutes after the last thunder clap or lightning bolt, Lehtola said.

To judge how far away lightning is, she said, measure the time between seeing the bolt or flash and hearing the thunder that follows.

“You can gauge the number of seconds between the thunder and lightning on your watch or by counting by 1,000s,” she said. “Every five seconds between when you see lightning and you hear thunder means the lightning is a mile away.”

Uman offered more tips on avoiding being hit by lightning:

Avoid standing above the surrounding landscape in an open field or on a beach.
Stay away from wire fences, rails and other metallic paths along the ground that could carry lightning currents to you.
If you’re in a small boat or swimming, come ashore, since the electrical current from a nearby strike can flow through the water to you.
Take shelter in a house or building with a floor, electrical wiring and plumbing or in a car with the windows rolled up. Golf carts are unsafe.
In open spaces, lie down or crouch in a ravine or valley. If no ravine or valley is nearby, get in any depression in the ground.
In a wooded area, seek shelter in a thick growth of small trees. No one tree is more likely to be hit than any other.
If a person is struck by lightning, Lehtola said, it’s important not to assume they are dead simply because their heart has stopped beating or they have stopped breathing.
“More than 80 percent of lightning victims survive, but it’s important to improve a victim’s chances by administering CPR,” she said. “It’s tragic that most people don’t know what to do.”

More information on lightning safety is available at http://www.lightningsafety.com/nlsi_pls.html, the Web site of the National Lightning Safety Institute, and more information on agricultural safety is available at http://agen.ufl.edu/~clehtola/agsaferef.htm, the Web site of the Florida Agsafe Network.