This week is National Lightning Safety Awareness Week, timed because summer is peak lightning season. John Jensenius, a lightning safety specialist with the National Weather Service, told National Geographic that summer is also the most dangerous time when it comes to lightning.
"Many people enjoy leisure activities in the summertime when the weather is nice, and lighting peaks in the summer, so that combination can be deadly," said Jensenius.
Jensenius and colleagues at the National Weather Service released a study this week that found that 64 percent of lightning deaths in the U.S. since 2006—152 out of a total of 238 deaths—occurred while people were involved in leisure activities. Of those leisure activities, recreational fishing topped the list with 26 lightning-related deaths.
Camping was next in line with 15 deaths, followed by boating with 14 deaths, soccer with 12 deaths, and golf with 8 deaths. The remaining 77 deaths by lightning occurred among those enjoying a variety of outdoor activities, including swimming, relaxing at the beach, running, walking, riding recreational vehicles, and picnicking. One man died in a parking lot of a NASCAR event in Pennsylvania in August 2012.
Between 2006 and 2012, 82 percent of people killed by lightning were male, reported the National Weather Service. Most were off the clock, because in recent years, only a handful of Americans have been killed by lightning while at work, including a few farmers and utility workers, said Jensenius.
The National Weather Service kicked off a major lightning safety awareness campaign in 2001. Prior to that, lightning killed an average of 73 people each year in the United States. After their campaign, the average dropped to 37. Seven people have died from lightning strikes so far this year.
The National Weather Service team produced this year's study by combing through media, medical, and eyewitness reports. Jensenius said statistics suggest that a person has about a 1 in 10 chance of dying after being struck by lightning.
"The two factors that most determine whether a strike will be fatal are how much electricity goes through the body and whether there is someone else there who can provide help," said Jensenius. The main factor that affects the amount of electrical current is how close the person is to the actual bolt. A direct hit is more likely to be fatal, he said, although it is more common to be hit by lightning after it first strikes a taller object, then dissipates the electricity across the ground.
One of the most serious effects of a lightning strike is possible cardiac arrest, said Jensenius. If there is someone nearby to call for help, and then administer CPR or use defibrillators, that can increase the risk of survival, he noted.
Jensenius said historically, farmers were at higher risk of lightning strikes than in recent years. In part, that was because there were many more of them in the U.S., but also because in the middle of the 20th century, they typically rode unprotected on the top of tractors. Today's farmers are likely to be enclosed in hard-top tractor cabs, which serve as good lightning protectors, said Jensenius. Ranchers and farmers who are in fields on horseback or foot can still be at risk, he warned.
Similarly, commercial fishers are likely to work in boats that can offer some protection against lightning. In contrast, recreational fishers are often on foot at water's edge, or cruising waterways in small, open-topped boats. There are also a lot more of them than commercial fishermen, said Jensenius.
Jensenius said the biggest risk to fishers, boaters, and campers is "not recognizing the threat." He said, "People should listen to the forecast, and if thunderstorms are predicted, they need to get to a safe place quickly."
That would include a hardtop metal vehicle or a substantial building, with four walls, he said. "If you can hear thunder you can be struck," he said, adding that boating can pose a particular risk if people can't hear thunder over the roar of an engine.
"A problem with camping can be not having a safe place to go," he added.
Lightning deaths among golfers have been steadily dropping, Jensenius said, thanks to rising awareness about the need to seek shelter during storms, especially among golf course operators. A few years ago, an average of four golfers were dying a year from lightning strikes, but that number has dropped to about one per year.
When it comes to large events, such as NASCAR races, Jensenius said it pays to pay attention to forecasts and plan ahead, since crowds can mean it takes a while to reach safety. "We do have recommendations that large venues have plans to keep people safe, and people should have responsibility for getting to a safe place," he said.
About the higher rate of lightning fatalities among men, Jensenius said it's possible more men are spending more time outdoors, although he asked, "Are men more aware or less aware about the dangers of lightning? Are they less willing to be inconvenienced by the lighting threat? It's hard to get stats on that sort of information, but I think that's certainly a factor in it."
As far as how other countries may be affected by lightning strikes, Jensenius said he doesn't have any specific data. "But I can say that in many developing countries where there are a lot of thunderstorms there are many more people killed than here, largely because they don't have as many safe shelters."
Lightning Safety Tips
"The general rule is, when thunder roars go indoors, because there is no safe place outside in a thunderstorm," said Jensenius.
Sturdy buildings are best, since tents and temporary shelters provide little protection, he said. If no buildings are available, hardtop vehicles can work.
When indoors, stay away from items that could conduct electricity, such as wires, corded phones, any type of plumbing (sinks, showers, and so on), and windows and doors, which often have metal parts that can conduct electricity inside, he said.
Wait 30 minutes after the last thunderclap or bolt of lightning before returning outside.
If your hair starts sticking up or you feel a tingling sensation, "that's a very bad sign," said Jensenius. It means a lightning strike may be imminent, and you should seek cover immediately.