June 5, 2009 -- After Tuesday's lightning strike, 12-year-old Chelal Matos' death in Virginia's Spotsylvania County brought the tally of lightning-related fatalities to six this year, including a woman who was killed by an indirect lightning strike in California last month.
Lightning is second only to floods as the deadliest natural threat, claiming about 58 lives each year, according to data from the National Weather Service. Yet the awesome electrical power of a lightning bolt, whether it hits a person directly or indirectly, can leave significant, lasting physical and mental damage, including burns, vision loss and personality changes.
"Lightning is a much larger problem than most people think," said Dr. Jonathan Adler, an attending physician in the Department of Emergency Medicine at Massachusetts General Hospital.
According to John Jensenius, a lightning safety expert at the National Oceanic and Atmospheric Administration, the average lightning bolt carries 20,000 to 30,000 amperes of charge and about 300 million volts.
A direct hit occurs when all of the lightning's energy is directed through the body or over the body on the skin. Although Adler said these kinds of strikes account for only 4 percent of all reported strikes, they are the most dangerous.
"When people are struck, current travels around the body, and sometimes people do surprisingly well, or through the body, which is a more severe injury and very broad," Adler said.
Lightning Can Shut Down Body Functions
An intense shock can severely impair most of the body's vital functions. Cardiac arrest is common.
"Commonly, when there is a strike that affects the heart directly, there is a massive shutdown," Adler said. "With every beat the heart depolarizes and changes its electrical signal. The heart flat-lines ... and stays that way for some time."
In addition, Adler pointed out that the shock can temporarily paralyze the diaphragm and knock out circuits in the brain that instructs the body to breathe.
"If a person gets CPR right away they have a better chance of survival," Adler said.
Post-Lightning First Aid Is Crucial
But CPR must continue for a long time because it takes a long time for the heart to beat again, the diaphragm to function, and even longer for the brain to reboot and control vital organ functions. People who go into cardiac arrest have a 75 percent mortality rate.
Chelal received CPR from two nurses who were on the scene, according to First Sgt. Liz Scott of the Spotsylvania County Sheriff's Office, but he did not survive. A second boy who was walking close to Chelal when he was struck was also injured from the bolt, possibly through a secondary encounter.
Chelal's friend is still in critical condition, Scott said.
Secondary Exposure Can Be Deadly, Too
While direct hits are dangerous, secondary encounters are more common but can be just as perilous. Ground currents, which occur when lightning strikes an object or the ground and the electricity travels through the ground until it encounters another object, such as a person, make up about 50 percent of lightning injuries.
Another common way to be struck is through a side flash, or a splash, when lightning that has struck an object seeks a path that lets it jump through the air to a second object.
Whatever the variety, there are long-term consequences for survivors of lightning strikes. People can develop problems days, weeks or months after the event.
Adler said survivors and their families should watch for changes in personality or areas of mental function. Survivors often lose their ability to concentrate on tasks such as reading for long periods of time, finding it uncomfortable. Some people find they have poorer mathematical skills.
"It's like a traumatic brain injury where people are not OK in some way," Adler said.
Because currents often flow into the body through the eyes and ears, patients may also experience vision loss, cataracts and hearing loss.
The most fortunate people are those for whom the lightning travels over the skin rather than through the body, leaving them with damage, but largely in the form of burns.
Precaution Is Key for Lightning Safety
There is no way to predict how a bolt of lightning will behave for any particular person, based on age or height or medical condition. But people who spend significant amounts of time outside, particularly in areas where there is a lot of lightning activity, are most at risk.
Texas receives more lightning strikes each year than any other state, about 1.9 million, with Florida in second place with about 1.3 million strikes.
Such accidents can often be avoided by attending to weather warnings and practicing proper lightning safety, Jensenius of the National Oceanic and Atmospheric Administration said.
"It's a question of being in the wrong place at the wrong time," Jensenius said. "There is no place that is safe outside. ... An awful lot of energy moves along the ground when lightning strikes."
Common misconceptions can impede lightning safety practices. For instance, metal objects do not attract lightning any more than other objects. Height is the determining factor in where it will strike. A taller object makes it easier for electricity to trace a path to earth from high in the clouds.
The safest place to go at the first rumbles of thunder, which signal striking range, is in a substantial building or a car.
"Many of the people involved [in lightning accidents] were involved in normal recreational, day-to-day activities," Jensenius said. "If they had taken shelter sooner, they would have been safe."
Still, Jensenius said the average number of lightning-related fatalities each year is decreasing because people are more proactive about lightning safety. As recently as last year, the average yearly fatalities were about 62 people. During the early part of the 1900s, that number was as high as 400 fatalities per year.
"The key to reducing fatalities is really in planning ahead," Jensenius said. "If they hear thunder, they are within striking distance of a storm. ... And stay inside after the thunder has died for 30 minutes afterwards."