Afternoon sea breeze storms bubbled up across North Carolina on the night of Aug. 20. The next morning, a maintenance worker at Eagle Creek Golf Club in Moyock, N.C., made quite the discovery.
A photo posted to Facebook by the club shows shards from the fiberglass pin blasted across the green, a branchlike fractal pattern of scorched earth. The likely culprit? Lightning.
There were isolated storms in the area on the evening of Aug. 19. Most were air-mass thunderstorms that had bubbled up in the heat of the day, helped by an encroaching sea breeze. Rain broke out around 5:45 p.m., with a heavy pulse thunderstorm stalling over the golf course between 6:45 p.m. and 7:15 p.m. While no one was on the 7th hole — a 164-yard par 3, by the way — to see the lightning, there was little doubt that it was behind the unusual ground markings. After all, there’s not a lot that can very easily heat grass to five times hotter than the surface of the sun in a pattern like that.
The resulting tracings are called a Lichtenberg figure. They’re formed when high-current electricity passes through insulating (nonconducting) objects. As the pent-up current discharges, it branches into the material, all the while breaking off into smaller and smaller veins of electrons. Since like charges repel, individual arteries tend to spread apart and not cross.
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Lightning itself is sometimes a 3-D Lichtenberg figure! After all, air is nonconducting. When you see a bolt leap between the cloud to the ground, that is not a Lichtenberg figure, since it’s a complete, continuous channel. But those fleeting branches before the connection of the main channel are Lichtenberg figures. So is cloud-to-air lightning.
3-D Lichtenberg figures can even occur below ground during discharges. And instead of torching grass, the superhot current fuses silica-based sand into a rocky fulgurite.
Charge flows the same whether we see it. So while the effect of lightning producing a beautiful pattern on the ground is not rare or novel, being able to see the ephemeral pattern frozen in time such as this is relatively uncommon. Thanks to the canvas of rug-like grass, the current was able to char material where it passed through. Ingenious entrepreneurs have turned the same premise into a souvenir opportunity.
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Most of the time when we can see these patterns left by lightning strikes, it’s on a golf course. It seems to happen with decent regularity across the United States.
The Lichtenberg pattern from last week’s storms underscores an extremely important crux of lightning safety: You do not have to be directly struck to be electrocuted. Even several yards away from the pin, charge was still crawling along the ground. That’s why you’re warned to never seek shelter beneath a tree in a thunderstorm. If the tree is struck, it will branch out through the roots and across the ground nearby.
That advice went ignored on Saturday, when six people were injured at the PGA Tour Championship in Atlanta when lightning struck a tree on the 16th fairway. The strike occurred at 4:45 p.m.; play had been suspended at 4:17 p.m., fans told to seek shelter nearly a half-hour earlier.
The tree near the range at 15 green/16 tee where lightning struck. PGA Tour says four people injured and their “latest report is that their injuries do not appear to be life-threatening.” pic.twitter.com/ORzHPMcVx1
— Zach Klein (@ZachKleinWSB) August 24, 2019There were no severe thunderstorm warnings in effect at the time of either last week’s strike or the more recent one in Atlanta. That’s because lightning isn’t a criterion.
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“We don’t issue warnings for lightning,” said Mike Montefusco, a meteorologist at the National Weather Service in Wakefield, Va.
Severe thunderstorm warnings are issued only for winds of 58 mph or greater or hail an inch in diameter or larger. All thunderstorms produce lightning; your personal responsibility is to locate and move to safe shelter. Never wait to be directed there by officials.
In the meantime, Eagle Creek Golf Club in North Carolina is thankful the strike occurred at night when nobody was on the course.
“We … would like to congratulate GOD on his almighty hole in 1,” they wrote.
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