UP expert details the true, terrifying nature of lightning

There is a common misconception that most lightning victims are struck directly by a “bolt” of lightning from the sky. But according to Professor Ryan Blumenthal, a senior specialist forensic pathologist at the University of Pretoria, less than 5% of victims are struck by the lightning flash itself – most lighting-related deaths and injuries occur as a result of other lightning attachment mechanisms.

“A direct lightning strike is probably one of the quickest deaths anyone could have,” Prof Blumenthal says. “The victim is injected with millions of amps and billions of volts. The victim will not see it, hear it or even feel it.”

However, in a recent review article in the Journal of Clinical Pathology, Prof Blumenthal placed focus on how the attachment mechanisms of lightning function to hazardous effect. These mechanisms are behind most deaths or injuries, and include an indirect lightning strike (touch potential), side flash, step voltages (ground potential or Earth Potential Rise – EPR), upward streamers, and blast waves (barotrauma), which surround lightning’s luminous channel.

Lightning can cause a wide range of injuries to both humans and animals. This field of research is known as keraunomedicine or keraunopathology. 

Lightning is measured by ground flash density. “This is the amount of lightning that strikes an imaginary piece of ground (one square kilometre) a year,” explains Prof Blumenthal. “Giant’s Castle in the Drakensberg mountain range registers a lightning strike rate of 26 flashes per square kilometre each year. This means that one square kilometre of land in the Giant’s Castle region will be struck, on average, 26 times a year.”

Touch potential accounts for approximately 15 to 25% of casualties. This occurs when lightning travels through a metallic object into a person and they are struck indirectly by touching the metal object. This object could be a corded telephone or a television set that is connected to the grid.

Side flashes are another source of danger, where high voltage passes through a tall object such as a tree or pole, then discharges into a person standing close by. This mechanism accounts for about 20 to 30% of casualties.

“An animal standing near a struck object or close to a flash of lightning to the ground could be injured by step voltages produced by a lightning current flowing through the resistance of the soil (EPR),” explains Dr Blumenthal. “This earth current can then flow along another pathway – up one limb and down another, which could result in injury or even death as, in some animals, the heart is located between the limbs.” EPR is the chief reason large groupings of animals are killed by lightning. It is uncertain what effect this mechanism has on humans.

Another significant cause of death or injury by lightning is upward streamers – which accounts for about 10 to 15% of lightning-related injuries and deaths – where electric fields travel both down from the sky and up from the ground. In such cases, currents can rise up through a person’s body towards the sky, travelling through their heart and brainstem, before the charge collapses back to earth. This could cause arrhythmia and death.

There are also cases where shock waves (barotrauma) emanate from lightning’s luminous channel. Barotrauma can occur when a person is very close to the point of the strike. Thunder can be heard from as far away as 25km; this means there is a significant blast wave surrounding lightning’s luminous channel. This blast wave can tear and tatter a victim’s clothes, rupture eardrums, cause secondary missile formation (shrapnel) as well as conditions such as pneumomediastinum (the abnormal presence of air or gas in the thorax).

Click on the infographics in the sidebar to learn more about lightning and what to do (or not do!) during an electric storm. View the gallery in the sidebar to see some of South Africa's incredible lightning. 

Prof Ryan Blumenthal

December 2, 2021

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  • Professor Ryan Blumenthal
    Professor Ryan Blumenthal – MBChB (Pret), MMed (Med Forens) Pret, FC For Path (SA) Dip For Med (SA) PhD (Wits) – is a senior Specialist Forensic Pathologist and Associate Professor in the Department of Forensic Medicine at the University of Pretoria (UP).

    He has published widely in the fields of lightning, suicide and other areas involving the pathology of trauma. He published his first article in 2004 and has since published 29 articles. Prof Blumenthal has also been involved in the publication of several textbooks, and has helped generate both national and international standard operating procedures and guidelines. His chief mission is to help advance forensic pathology services both nationally and internationally. His life’s work has been dedicated to education, critical thinking and puzzle-solving.

    Forensic pathologists take part in exercises in preventative medicine – in fact, forensic pathology might better be called community and public safety pathology. (Wright RK, Tate LG. Forensic pathology. Last stronghold of the autopsy. Am J Forensic Med Pathol. 1980 Mar;1(1):57-60. doi: 10.1097/00000433-198003000-00009. PMID: 7015831).

    No other field in medicine offers the intellectual challenge of forensic pathology, as it requires a working knowledge of diagnosis and treatment in almost every speciality of medicine. It also calls for an understanding of non-medical fields such as criminology, criminalistics, engineering, highway design, police science and a deep understanding of a community – its mores, folkways and religion.

    The professor believes that UP is an enabling institution when it comes to research. His research into lightning contributes to society because lightning medicine forms part of wilderness medicine, which is a field of medicine that provides vital emergency care in remote settings. This forms part of environmental health, which encompasses severe weather threats to life and property. Humans interact with electricity almost every day, yet electropathology and lightning research are still emerging as fields of research.

    Prof Blumenthal is also involved in collaborative research with several other departments and universities, both locally and internationally. He recently published a book titled Autopsy – Life in the Trenches with a Forensic Pathologist in Africa, which became a non-fiction best-seller in South Africa. He also hosted an eight-part documentary series called Lightning Pathologist, which aired on People’s Weather and was viewed by more than 2 million people. Both the book and the series have had a significant public health impact. Going forward, Prof Blumenthal would like to continue with the public communication of science.

    He says he is inspired by those who have won the Nobel Prize. His academic role model is Alfred Nobel, who, in his will, left most of the proceeds of his large private fortune for the establishment of a prize “for the greatest benefit of humankind”.

    In terms of what Prof Blumenthal hopes to achieve with his academic work and research, he says, “I hope to continue planting little acorns,” drawing from a quote by mathematician Richard Hamming: “When you’re famous, it is hard to work on small problems. The great scientists often make this error. They fail to continue to plant little acorns from which the mighty oak trees grow. They try to get the big thing right off. And that isn’t the way things go.”

    Prof Blumenthal’s hobbies include solving puzzles, playing chess, sleight-of-hand magic, birdwatching, mountain biking and writing novels.
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