How to tell how far away lightning is by counting
Did you see a flash of lightning? Start counting, because that can tell you how far away the thunderstorm is, and if it's time to head indoors.
Lightning flashes from a thunderstorm light up the landscape in eastern Brandenburg. (Photo by Patrick Pleul/picture alliance via Getty Images)
When thunder rumbles in the distance, there’s a quick and simple way to figure out how close the lightning actually struck based on the speed of sound.
After you see a flash of lightning, start counting. It takes about 5 seconds for the sound of thunder, which originates from lightning bolts, to travel 1 mile. If you can count to 10 between seeing the lightning and hearing the thunder, then the flash occurred about 2 miles away.
This trick works because light travels much faster than sound. Lightning is visible almost instantly, while thunder takes time to reach your ears, depending on how far away the strike occurred.
A few seconds of counting can do more than satisfy curiosity; it can also help you stay safe when a storm is approaching.
Lightning can strike even if it’s not raining directly overhead. That’s why experts recommend moving indoors as soon as you hear thunder and staying there for at least 30 minutes after the last rumble.
Even indoors, there are ways that lightning can still shock you.
"If lightning strikes your home, it typically follows either the wires or the plumbing," lightning safety expert John Jensenius of the National Lightning Safety Council told AccuWeather. This means taking a shower or washing dishes could be dangerous during a storm.
On July 19, a lightning strike shocked a gamer who was live-streaming during a thunderstorm in North Carolina, causing him to jump from his chair. A few weeks earlier, a 19-year-old was injured after being struck by lightning while using her phone, which was plugged into the wall when the bolt hit nearby.
“Lightning is a threat anywhere in the U.S.,” Jensenius says. “The key is planning ahead.”
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