Johannesburg - We love our summer lightning storms. The dramatic thunder, split through by bolts of crashing light, that herald many a late summer afternoon are a fantastic piece of outdoor theatre.
But lightning is also dangerous, even deadly. Last month, lightning struck and killed Protea Glen schoolgirl Bertha Ncube,16, while she was on her way home from school in a group.
The next day, lightning struck nine boys, aged between 16 and 18, at King Edward VII School (KES) in Houghton while they were pulling the covers over the cricket pitch. Luckily, a parent with paramedic training was near and resuscitated two of the boys who went into cardiac arrest. All of them survived.
According to the South African Weather Service, more than 260 people are killed by lightning in the country each year. The real toll, though, is probably much higher, says Estelle Trengove, a Wits School of Electrical and Information Engineering PhD graduate who has done extensive work on lightning.
“It’s likely a lot more people in rural areas have been struck by lightning but the incidents never get reported,” she says. For every one person killed by it, about 10 people are injured by lightning, she adds. Lightning also injures and kills livestock, and damages property.
So it’s a good idea to know how lightning acts and how to protect yourself from it. Also there are common myths around lightning that need to be dispelled.
Those most vulnerable to lightning are people in rural areas, who spend much of their time outdoors. “In cities, you have sturdy buildings and structures that protect you, with electrical wires and pipes that can conduct the current away from you,” says Trengove. “In rural areas structures tend to be flimsy, so people could also get injured even if they’re inside their house.”
Many people in these remote areas believe that trees are immune to lightning, thus they take shelter under a tree. “A tree doesn’t protect you. In fact it can endanger you, because if lightning strikes a tree, the electrical current will travel down the trunk to the ground, but side flashes of the main current may strike you on its way if you are in the vicinity.
“Also, once the current reaches earth, it disperses radially in the ground like ripples, becoming less potent as it moves along. People, who have a lot of moisture in their bodies, could be better transmitters of electrical current than the ground, so if you are near a direct strike your body could be the path of least resistance and a current could travel through you,” says Trengove.
So what happens if you’re struck? If lightning strikes you directly, it may be fatal. It stops your heart and/or breathing – caused by vascular spasm and/or neurologic damage, and immediate resuscitation is required.
In most cases, however, the victim is superficially burnt. The location of where the electrical current was transmitted is red and can spread out like a feather or a spray of spots.
Lightning also typically causes injury to the nervous system, with after-effects ranging from short-term loss of consciousness to long-term impairment of brain.
An American study found that 70 percent of lightning victims suffer a brief loss of consciousness, and that more than 80 percent have confusion with amnesia (memory loss) and passing sensations of tingling, pricking or burning.
In her research, Trengove looked at dangerous myths about lightning, such as sheltering under a tree, and myths which are harmless and don’t need to be dispelled.
Many rural communities believe in witchcraft, for instance, and that lightning is the work of witches. People make muthi to protect themselves from it.
“One of my fourth-year students told me he believed in natural lightning, and man-made lightning, in other words, lightning made by witches. So it’s a belief that continues through the generations. I don’t think it’s a belief that is important to change,” she says.
There is also a belief in KwaZulu-Natal in a mythical snake called inkanyamba, which lives in deep water pools. “It’s believed that when the inkanyamba wants to find a mate, it flies through the sky in a malevolent storm cloud, accompanied by lightning. When it sees a glinting pool, it dives down to see whether there is a mate in the water. The inkanyamba could mistake a shiny corrugated tin roof for water and dive down from the sky, hence some people believe one should paint a corrugated tin roof.
“In a similar vein, many people from different cultural groups cover their mirrors during a lightning storm, thinking the mirror could attract lightning, or that the reflection of the lightning could kill them. These are also harmless myths that are not important to change,” says Trengove.
Westernised myths include the belief that wearing rubber-soled shoes or putting a rubber tyre on your roof will protect you from lightning. “Rubber doesn’t protect you from such a forceful current of electricity. But being inside a car, or airplane does, because it forms a metal cage around you, and the electrical current is dispersed through this metal shell, called a Faraday cage,” explains Trengove.
People are correct in believing that being on a landline phone is dangerous, because the electrical current could travel through the phone wire. “This belief has transformed into a myth, however, about speaking on a cellphone. Actually, speaking on a cellphone is quite safe,” she says.
In dispelling myths, it helps to understand the physics of lightning. In short, lightning is generated in an electrically charged storm. The flashing bolt you see is an electrical discharge that occurs between regions of positive and negative electrical charges in the atmosphere. It transmits from a cloud to itself, a cloud to a cloud or a cloud to ground, and is usually accompanied by thunder, but not always.
When it travels towards the ground, lightning seeks the path of least resistance in finding the opposite charge (as lightning is usually negatively charged, it seeks clusters of positive charge).
High points, such as trees, mountains, poles or tall buildings, are preferred pathways for lightning, sending upward-moving discharges (called upward leaders) which connect with the downward lightning discharge. The point of connection is when you hear and see the flash.
Thus many schools and buildings have set up lightning warning systems, with a siren remotely triggered and notifications sent by text message. Some buildings have erected lightning rods that take the brunt of lightning bolts and conduct them safely to ground.
Early warning systems are useful, as the threat can be present a while before you see a thundercloud appear, or disappear.
“Lightning often occurs around the edges of a thundercloud, so it doesn’t have to be raining. Lightning has been known to strike up to 20km away from the centre of a thundercloud,” says Trengove.
So if you’re aware of a lightning storm coming, best to head for a solid building and watch nature’s theatre from the window.
MYTHS AND TRUTHS – FROM THE SA WEATHER SERVICE
Lightning never strikes the same place twice.
Fact: Actually it does, often, especially if it’s a tall, pointy, isolated object. The Empire State Building is hit nearly 100 times a year. The Drakensburg mountains get more strikes than Joburg.
If it’s not raining or there aren’t clouds overhead, you’re safe.
Fact: Lightning often strikes up to 5km from the centre of the thunderstorm, far outside the rain or thunderstorm cloud.
Rubber tyres on a car protect you by insulating you from the ground.
Fact: Most cars are safe from lightning, but it is the metal roof and metal sides that protect you, not the rubber tires.
If you touch a lightning victim, you’ll be electrocuted.
Fact: The human body does not store electricity. It is perfectly safe to touch a lightning victim to give them first aid.
If outside in a thunderstorm, you should seek shelter under a tree.
Fact: Being underneath a tree is the second leading cause of lightning casualties. Better to get wet.
If you are in a house, you are 100 percent safe from lightning.
Fact: A sturdy house is a safe place to be during a thunderstorm as long as you avoid anything that conducts electricity. So stay off landlines, wires, TV cables, electrical appliances, computers, plumbing, metal doors and windows.
If thunderstorms threaten while you are outside playing a game, it is okay to finish it before seeking shelter.
Fact: Many casualties occur because people do not seek shelter soon enough.
Structures with metal (jewellery, cellphones, MP3 players, watches, etc) attract lightning.
Fact: The presence of metal makes no difference on where lightning strikes. Mountains are made of stone but get struck by lightning many times a year. While metal does not attract lightning, it does conduct it so stay away from metal fences, railings, bleachers, etc.
If trapped outside and lightning is about to hit, lie flat on the ground.
Fact: Lying flat increases your chance of being affected by ground current. If you are caught outside in a thunderstorm, keep moving toward a safe shelter. (Trengove suggests if you’re not near a building, squat down and make yourself as small as possible so you are less likely to be a router for the current.) - The Star