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Few People Die From Lightning Strikes These Days. Why?

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This decade will go down in weather history as one of the wildest in modern times. Since 2010, we’ve seen both the widest and strongest tornado on record touch down in Oklahoma. Mexico felt the wrath of the strongest hurricane ever recorded in terms of wind speed. The American West is enduring a years-long drought with no end in sight. But it’s not all bad news. This decade is also on track to see the lowest number of lightning deaths we’ve ever recorded in the United States, and that’s quite the accomplishment.

Lightning is an underestimated killer. We’re so used to thunderstorms that their presence is almost second nature unless they’re unusually strong. Scientists estimate that we see about 16,000,000 thunderstorms around the world every year, and the United States alone averages about 22.5 million flashes of cloud-to-ground lightning in a typical year. That’s a little nerve-wracking when you consider that a single bolt of lightning is hotter than the surface of the sun and packs enough electricity that a direct strike to your body can stop your heart before you have time to react.

Most people who are struck by lightning survive the frightening encounter, though with some serious lingering effects. Lightning is usually only deadly when the electrical charge crosses a victim’s heart and causes it to stop beating, and even then they can be revived if a fast-acting bystander performs CPR. Given the amount of lightning that crashes around us on a regular basis, you’d expect the number of lightning deaths in the United States to be sky high, right? Surprisingly, no: Since 2010, we’ve only seen an average of 26 people die each year due to lightning strikes.

Just over two dozen lightning deaths every year sounds like a big number, sure, but the overall downward trend of lightning fatalities over the past 75 years is one of the most incredible weather statistics out there.

A chart showing the number of reported lightning deaths each year between 1940 and 2015. Chart: Dennis Mersereau

We’ve seen a steady decline in the number of lightning fatalities almost every year since recordkeeping began back in 1940. During the 1940s, you could expect an average of 329 people to die as a result of a lightning strike every year. By the 1960s, the average number of fatalities had dropped by more than half to just 133 deaths per year. The new millennium brought about an average of just 41 lightning deaths per year, and the number continued to slowly tick down with time.

Why are we seeing fewer lightning deaths in the United States than ever before? It’s more complicated than any one cause, but there are at least three major factors at play. The first is the most obvious—you’re probably reading this article indoors at your computer or on your phone. If you were around in the middle of the 20th century and didn’t live in a city, you spent significantly more time outdoors for both work and play than we do today. The simple act of more people spending more time indoors is a significant factor in the rapid drop-off in lightning fatalities.

Another major factor was the invention of weather radar after World War II. Before radar came into widespread use, threatening clouds on the horizon or distant rumbles of thunder were your only clues that a thunderstorm was on its way. If a storm is close enough that you can hear thunder, you’re close enough to be struck by lightning. Weather radar took the surprise out of approaching storms, and now we can watch bad weather roll toward us before you can even see the clouds out your window.

The third factor likely has to do with education. We know so much more about the weather today than we did a few decades ago, let alone in the middle of the 1900s. Weather safety education in school, on the Internet, and through efforts by organizations like the National Weather Service—“when thunder roars, go indoors!”—have helped tremendously in raising public awareness about the dangers of lightning and how to find safe shelter when a storm bubbles up. 

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Big Questions
What Causes Sinkholes?
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Mark Ralston/AFP/Getty Images

This week, a sinkhole opened up on the White House lawn—likely the result of excess rainfall on the "legitimate swamp" surrounding the storied building, a geologist told The New York Times. While the event had some suggesting we call for Buffy's help, sinkholes are pretty common. In the past few days alone, cavernous maws in the earth have appeared in Maryland, North Carolina, Tennessee, and of course Florida, home to more sinkholes than any other state.

Sinkholes have gulped down suburban homes, cars, and entire fields in the past. How does the ground just open up like that?

Sinkholes are a simple matter of cause and effect. Urban sinkholes may be directly traced to underground water main breaks or collapsed sewer pipelines, into which city sidewalks crumple in the absence of any structural support. In more rural areas, such catastrophes might be attributed to abandoned mine shafts or salt caverns that can't take the weight anymore. These types of sinkholes are heavily influenced by human action, but most sinkholes are unpredictable, inevitable natural occurrences.

Florida is so prone to sinkholes because it has the misfortune of being built upon a foundation of limestone—solid rock, but the kind that is easily dissolved by acidic rain or groundwater. The karst process, in which the mildly acidic water wears away at fractures in the limestone, leaves empty space where there used to be stone, and even the residue is washed away. Any loose soil, grass, or—for example—luxury condominiums perched atop the hole in the ground aren't left with much support. Just as a house built on a weak foundation is more likely to collapse, the same is true of the ground itself. Gravity eventually takes its toll, aided by natural erosion, and so the hole begins to sink.

About 10 percent of the world's landscape is composed of karst regions. Despite being common, sinkholes' unforeseeable nature serves as proof that the ground beneath our feet may not be as solid as we think.

A version of this story originally ran in 2014.

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DNA Analysis of Loch Ness Could Reveal the Lake's Hidden Creatures
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Stakeouts, sonar studies, and a 24-hour video feed have all been set up in an effort to confirm the existence of the legendary Loch Ness Monster. Now, the Associated Press reports that an international team of scientists will use DNA analysis to learn what's really hiding in the depths of Scotland's most mysterious landmark.

The team, led by Neil Gemmell, who researches evolutionary genetics at the University of Otago in New Zealand, will collect 300 water samples from various locations and depths around the lake. The waters are filled with microscopic DNA fragments animals leave behind as they swim, mate, eat, poop, and die in the waters, and if Nessie is a resident, she's sure to leave bits of herself floating around as well.

After extracting the DNA from the organic material found in the water samples, the scientists plan to sequence it. The results will then be compared to the DNA profiles of known species. If there's evidence of an animal that's not normally found in the lake, or an entirely new species, the researchers will hopefully spot it.

Gemmell is a Nessie skeptic, and he says the point of the project isn't necessarily to discover new species. Rather, he wants to create a genetic profile of the lake while generating some buzz around the science behind it.

If the study goes according to plan, the database of Loch Ness's inhabitants should be complete by 2019. And though the results likely won't include a long-extinct plesiosaur, they may offer insights about other invasive species that now call the lake home.

[h/t AP]

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