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Beware the body electric

By SUSAN ASCHOFF, Times Staff Writer
Published August 24, 2006

Related links
Map of lightning strikes across the United States, updated every 15 minutes:
LightningStorm.com


Information and safety tips from the experts:
LightningStorm.com


News on lightning injuries:
www.uic.edu/labs/lightninginjury


Center for lightning research at the University of Florida:
LightningStorm.com



Last week, lightning struck and killed a 16-year-old roofer in Wesley Chapel, ignited an apartment fire that left 14 families homeless in Bradenton, and exploded a 40-foot pine tree in Cape Coral, shattering windows, lifting roofs and hurtling debris across two blocks.

Florida is one of lightning's favorite targets. Odds that a bolt will strike a person in Florida are 1 in 80,000 - almost 10 times the risk nationwide.

The stretch from Tampa Bay to Orlando is the lightning capital of the United States. It is a dubious honor: Hillsborough, Polk and Pinellas counties top the list for lightning deaths.

Yet the lethal light show is irresistible: powerful, beautiful and dramatically random, a muse for scientists and the bane of power grids.

- SUSAN ASCHOFF, Times Staff Writer

Scientists make sparks fly

Researcher can't make lightning strike when and where they want.

At the University of Florida and other institutions, they create lightning for study by launching a 3-foot rocket fitted with a spool of copper wire into a thunderstorm. Lightning strikes the rocket and vaporizes the grounded wire, but a channel remains to carry current to the ground, where instruments collect data. (The scientists typically hide in a special trailer or building with no wire connections to invite lightning inside.)

What is lightning, really?

Lightning is a discharge between the positive and negative areas in a thunderstorm. Within a cloud, about 15,000 to 25,000 feet above sea level, raindrops freeze into ice. The ice particles grow, collide and break apart, acquiring electric charges within clouds and between clouds and the ground.

A cloud-to-ground flash moves downward in 50-yard sections called step leaders. The steps create a channel for the charge when a good connection is found.

This all takes less than a half second: The flash down travels at about 200,000 mph. The trip back up - the flash we actually see - is much brighter and moves at about 200-million mph.

Signs you are in big trouble

If you are out in the open and the hair on your head begins to stand on end, your skin tingles, a metal object vibrates, you see a corona discharge or hear a crackling or "kee-kee" sound, a lightning strike is imminent.

If no building is available, immediately crouch down with your feet together, tuck your head and cover your ears. Do not lie down. If you are with a group, spread out with several body lengths between each person.

Maybe Mother Nature didn't like his music

Colorado teenager Jason Bunch, listening to Metallica on his iPod while mowing the lawn July 2, suffered ruptured eardrums and burns where the iPod cord trailed across his torso when he was struck by lightning.

Just two weeks earlier, a pair of London doctors had said in a medical journal that talking on a cell phone or listening to an iPod could be dangerous in a thunderstorm.

Lightning is not lured by electronics, but electronics may serve as conduits. When a person is struck, skin conducts the force over the body rather than through it, called flashover. Some experts say a handheld device can disrupt the flashover, potentially causing serious injury.

Household appliances are trouble because they are typically connected to wires. Lightning follows wires and pipes into a house. Washing machines, dryers, faucets, doorknobs, computers, phones - all have transmitted lightning's charge to a coincidentally proximate human.

*   *   *

Tall tales

Lightning never strikes twice.

The Empire State Building and Sears Tower get hit thousands of times a year.

Golfer Lee Trevino has been struck twice.

A surge protector will save my computer.

A direct strike to your incoming power lines will likely fry anything plugged in, depending on the path the charge takes through your walls.

If lightning strikes, the water is safer than a metal boat.

If there is lightning, neither the boat nor the water is safe. But if you are hit and injured, you are better off in the boat.

Victims have been known to burst into flames.

Lightning can blow off your clothes while leaving few, if any, burns. When struck, people do not glow.

Don't touch a lightning victim because he is still charged.

People have died because no one would resuscitate them. Lightning victims are not charged, but their heart and breathing may have stopped and they need immediate help.

*   *   *

Get out of its way

There are about 25-million cloud-to-ground strikes annually in the country. Some experts say if you can hear thunder, you are not safe.

To determine how close a storm is, count the seconds between the lightning flash and the thunder and divide by 5 to estimate the distance in miles.

*   *   *

Anyone have a question?

Am I safe if my shoes have rubber soles?

Lightning can travel through thousands of feet of dry air. Do you really think a half-inch of rubber will save you? A vehicle is considered safer than outdoors not because it has rubber tires but because its metal shell conducts the electricity around you.

If my clothes are wet, am I doomed?

Wet clothes are a good thing. You may escape serious injury because most of the charge will travel around your body, rather than through it.

How about my cordless phone? No wire, no shock?

A cordless phone is safer than the plug-in variety. Just put some distance between you and the base.

Does my umbrella make me a target?

Daryl Mattison, principal of Golden Gate Elementary School in Naples, might think so. Mattison was struck last week while holding an umbrella in the school parking lot. He was not injured.

Carrying an umbrella increases your height. As a general rule, you want to be the shortest object around. On the remote chance you could be struck while carrying an umbrella, do you really want to ditch it and get drenched?

Sources: National Oceanic and Atmospheric Administration; National Weather Service; University of Florida Lightning Research Group; NASA Global Hydrology and Climate Center; Progress Energy Florida; University of Illinois at Chicago; ABC Science Onine; Society for Amateur Scientists; www.PBS.org; www.thedenverchannel.com; www.denverpost.com; www.pensacolanewsjournal.com; www.sploid.com; Times files and wires

For more information about lightning:

www.lightningstorm.com - A map of lightning strikes across the United States is updated every 15 minutes

www.lightningsafety.noaa.gov - Information and safety tips from the experts

www.uic.edu/labs/lightninginjury and www.lightning-strike.org - News on lightning injuries

www.lightning.ece.ufl.edu - Center for Lightning Research at the University of Florida

 

[Last modified August 24, 2006, 07:46:30]


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