June 16, 2008

Hear Thunder?

By Sheryl Ubelacker, Health Reporter, THE CANADIAN PRESS

Christina Wards could hear the thunder and knew a fast-moving storm was closing in, so she hustled her daughter Richelle and other teens practising baseball off the field towards their vehicles.

But as she and Richelle prepared to climb in their van, a bolt of lightning struck a nearby metal fence enclosing the sports field in their hometown of Dawson Creek, B.C. The flash travelled across the ground and engulfed the pair in a massive electrical jolt.

The force lifted Richelle off her feet and blew her across the van's interior, slamming her into the driver's side from the passenger door.

"She was screaming 'My feet, my feet,"' recalls Wards of that day last July. "My own arm was buzzing."

Richelle, now 16, had tingling, numbness and severe sensitivity in her feet and legs for a few days, but suffered no lingering effects.

As lightning strike survivors go, she was one of the lucky ones.

Each year, about 10 Canadians are killed after a close encounter with this dangerous weather phenomenon and an estimated 70 to 160 are injured, often severely.

A 29-year-old man was killed on the weekend after being struck by lightning while building a deck at his parents' Saskatchewan home. His mother was also hit and suffered serious burns.

For the roughly 10 per cent of those who don't survive a lightning strike, many die immediately from cardiac arrest - their heart stops beating from the shock of electricity surging through the body - or from devastating brain injury that can lead to death within days.

Those who do survive can sustain a range of injuries, from minor burns and broken ear drums to severe neurological trauma, says Dr. Mary Ann Cooper, a professor of emergency medicine at the University of Illinois in Chicago and a world-renowned expert on the medical effects of being zapped by lightning.

While most people survive the strike, they frequently have permanent health effects, including chronic pain, thought-processing difficulties and personality changes," Cooper writes in a section on the medical aspects of lightning posted on the U.S. National Weather Service's website. (Cooper was not available for an interview.)

"Patients have difficulty in all areas that require them to analyze more items of information than they can handle simultaneously," writes Cooper, noting that survivors may seem mentally slow, easily distracted and forgetful.

She says those walloped by lightning may initially experience intense headaches, ringing in the ears, dizziness, nausea and vomiting. Over time, they may become irritable and quick to anger because of damage to the brain's frontal lobe. Fatigue and depression are common among those who suffer physical disabilities as a result of a damaged nervous system.

And it's no wonder lightning injuries can be so devastating.

A bolt from the blue (or the grey, as the case may be) packs an incredible punch, with a median value of about 25,000 amps - hundreds of thousand of times stronger than the current in a typical house, says Ronald Holle, a meteorologist at Vaisala Inc., which operates lightning detection networks for the United States and Canada.

Lightning flashes travel from towering cumulus clouds to Earth at about 220,000 kilometres per hour. To put that into perspective, the world's fastest fighter jet reportedly has a top speed of about 2,100 km/h.

When lightning hits an object on the ground, its temperature can reach a sizzling 28,000 C.

"It's real hot," says Holle, with understatement.

About 25 million lightning bolts hit the United States and about two million strike Canada each year, mostly during the months of June, July and August, says Holle.

"The only thing that keeps people and things from being even worse impacted by lightning ... is that it only lasts a short time," he says. "It's only a few tenths of a second, a flash."

Holle said tall, isolated objects attract lightning. Contrary to popular belief, metal does not attract lightning but it does conduct it.

"The flash is coming down from the clouds and in a very simplified way it looks for the closest thing to hit when it gets close to the ground. And if it's a tree, it hits it, if it's a tower, it hits it, if it's a person, it hits it."

"And you cannot control, as a person you can do nothing, to absolutely control that path when you're outside. That's the underlying issue when it comes to safety."

Injury prevention experts have adopted an adage for the public: "When thunder roars, go indoors."

That means running to the nearest substantial building, like a house or store, or inside a fully enclosed metal-topped vehicle (no convertibles), Holle stresses.

"Those are the safe places. Everything else is not guaranteed, is not certain, and you cannot be sure that anything you do is going to work. It doesn't matter what you're wearing, carrying, holding or how you're standing."

Even huddling in an upright fetal position to make oneself as small a target as possible, as was once proposed for those caught outdoors in a thunder storm, is no guarantee of safety, he says.

But what if someone is on the sixth hole of a golf course and a storm suddenly blows in?

Holle won't even go there.

"We're stopping this 'what if' stuff and we're trying to get the point across that there are two really, really safe places" - a building or a metal-topped vehicle, he repeats.

That's not to say that being inside an automobile lambasted by lightning is a "happy place. It really can be quite bad."

In about half of cases in which vehicles are struck, the occupants emerge unscathed, while in the other half of cases, those inside come out with burns, numbness in their limbs and hearing loss.

The vehicle may not fare so well.

"Cars get a lot of damage," says Holle, who tracks lightning injuries. "Typically, what I found was the antenna was vaporized or destroyed or half-gone, the tires were blown. Good grief, 50,000 degrees (Fahrenheit) would take care of the tires."

Even inside a building, he advises people sheltering from a storm to keep away from plumbing and wiring and not to use corded telephones (cordless are fine).

"So when the house is hit - when, not if - you don't want to be touching the conducting parts," he warns. "Because the most likely thing is it won't hit the house directly, but it will hit a power pole outside and trace through the power lines and then it can leak into the phone lines and the plumbing in various ways."

"They're all made to conduct electricity. They're all water or metal and so you just don't want to be touching those when it hits because there are lots of people that happens to every year."


How to avoid getting zapped by lightning? 'When thunder roars, go indoors'

Some facts about lightning and tips to avoid getting struck:


-Lightning is attracted to tall, isolated objects like trees.

-Metal does not attract lightning, but is a prime conductor, as is water.

-Two-thirds of all lightning strikes occur in June, July and August; most occur in the afternoon.

-The average lightning flash packs enough power to light a 100-watt light bulb for more than three months.

-A large proportion of lightning deaths occur in, on or near open water. Many people also die sheltering under trees.

-Nowhere outside is safe from lightning.


-Heed the warning: "When thunder roars, go indoors!"

-Take shelter in a substantial building or fully enclosed, metal-topped vehicle. Avoid small structures such as beach cabanas or tents.

-When inside your home or other building, avoid using a corded telephone, except for emergencies. Cordless phones are safe.

-Avoid electrical appliances and plumbing. Don't wash dishes or take a bath or shower.

-Practise the 30-30 Rule: When you see lightning, count until you hear thunder. If it's 30 seconds or less, the storm is within 10 kilometres and dangerous. Seek immediate shelter. Wait 30 minutes after the lightning has stopped before going outside.

Sources: Environment Canada, U.S. National Weather Service, Vaisala Inc.