Lightning Safety Guide

Lightning is the second leading cause of death from natural disasters, behind only floods as the deadliest phenomenon in America. In the first 8 months of 2018, 17 Americans were killed by lightning. All but one of these was in the southeastern United States, and 82% were men.

According to the National Weather Service, 79% of all lightning deaths in the last ten years have been in June, July, or August. In summer, hotter weather brings more lightning storms at a time when people are more likely to be engaged in outdoor activities.

Despite the speed of a lightning strike, it is never the case that strikes happen from nowhere. Knowing what signs to look for, and how to be as safe as possible can hugely reduce your chances of being struck by lightning.

What is lightning and how is it dangerous?

Remarkably, there is not a scientific consensus on what causes lightning.

According to the National Geographic, some scientists have hypothesized that it is the presence of ice in a cloud that leads to lightning; positively charged ice crystals rise to the top of the cloud, and negatively charged crystal fall to the bottom. The large charge differentials that develop causes a discharge of current to the ground.

Lightning strikes can be extremely unpredictable. Lightning can strike 10 miles away from the thunderstorm that produced it, and potentially even further.

That means that you can be standing under a blue sky and be in danger from lightning. Furthermore, lightning’s range means it can strike well in advance of, or behind, a thunderstorm. Put another way, you don’t have to be standing too near to a thunderstorm for it to be dangerous.

How are people struck by lightning?

When one thinks of being struck by lightning, it is usually of someone in an open field, being hit directly by a strike. However, there are actually more common ways of being injured or killed during a lightning storm. Knowing how you can be hurt is a critical step in helping you to avoid dangerous situations.

Direct Strike

A direct strike is the simplest, if not the most common form of lightning strike A direct strike usually occurs when people are in open, exposed areas, and therefore form the highest point in the vicinity. A direct strike usually involves a flashover, where part of the current travels around the person’s skin.

This causes severe burns. More dangerous than the flashover, however, is the part of the current that travels through the victim’s body. If this passes through the cardiovascular or nervous systems, it can be deadly.

Side Flash

A side flash occurs when lightning hits a taller object near a victim. Most of the strike flows through the taller object, although a smaller portion of the current discharges ‘jumps’ into the victim. Side flashes usually take place when a victim has taken shelter from a storm or rain under a tree.

Side flashes can usually only move a foot or two laterally, although, under the broad canopy of a tree, the victim need not be directly next to the trunk for this to take place.

Ground Current

Ground current strikes are responsible for the highest number of lightning deaths to both humans and livestock. When lightning strikes an object, the current is dispersed through the ground immediately around the strike.

Effectively, the ground becomes electrified with a powerful current. This is common when lightning strikes man-made surfaces with conductive floors (such as garages), although can also take place in open fields.

Ground current enters the body at the point nearest the lightning strike and exits at the point further from the strike. Depending on the journey the current must take between these two points, it can enter the cardiovascular or nervous system and be fatal.

Conduction

Contrary to popular thought, metal does not attract lightning; however, when metal is struck by lightning, it does provide an excellent conductor and can guide and transport current for long distances. Conduction can impact even those indoors, as current travels down electrical and phone wires.

According to NOAA: “anyone in contact with anything connected to metal wires, plumbing, or metal surfaces that extend outside is at risk.”

Streamers

When lightning approaches the ground, many upward moving ‘streamers’ of charge actually move upwards to meet the strike. Only one of these streamers (usually) makes contact with the downward strike, connects the ground and the lightning, and causes the bright flash.

However, once the connection is made, all of the upward streamers discharge. Although streamer injuries are extremely rare, they can occur in proximity to a lightning strike.

What to do when there is a thunderstorm

Don’t stand near any metal structure. Because of metal’s conductive properties, lightning can travel quickly and long distances down metal structures.

If you are with a group, spread out over a larger distance, but maintain visible contact with one another. This is the last resort if you can’t find shelter; it may increase the chance of any one individual being struck by lightning, but it greatly diminishes the chance of multiple casualties and guarantees that there will be help available if someone does get struck.

What to do if someone is struck
by lightning

If someone has been struck by lightning, they will need immediate first aid. Lightning strike victims do not retain an electrical charge, and therefore will not cause a discharge of electricity onto anyone providing first aid. NOAA states ‘Cardiac arrest is the immediate cause of death for those who die (after being struck by lightning).’

Move the victim to a safer place if at all possible. It is very unlikely that a lightning strike victim has broken bones that can cause paralysis, so moving can be a safer course of action than remaining. If the victim is bleeding or has broken bones do not move them.