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Dig this Lightning
Alan Sealls, Copyright 2007 You're checking out at the supermarket. The rhythmic beeping of the grocery scanner puts you in a trance. Your eyes meander toward the tabloids. Just beneath the miracle diet headline is one about a mystery trench in a cemetery. "Cable TV for the Afterlife?" This is not real but the following is a true story. Late in the summer of 2007, a gentleman in west Mobile, Alabama, reported lightning had dug a trench in his family cemetery. I had heard of lightning trenches but never had I seen one. Curious whether the man was confused or pulling a prank I went to the cemetery to see for myself. The furrow was easy to spot. It looked just like somebody used a trencher to sloppily lay a cable line. I was blown away by the length and depth.  From the base of a tall oak tree a gash in the ground ran straight more than 60 feet to the east (from B to C) and branched outward. I was still a little skeptical so I looked further.  Walking around the
west side of the oak tree I spotted where bark had
been freshly peeled away in a vertical stripe along a high limb (A). It
continued on to a larger middle limb. This is a common sign of a
lightning strike although midway to the ground the stripe disappeared.
 There was no burn
or missing bark around the trunk but at the base of
the tree was a 12 inch deep hole (B), about 8 inches across with a burn
to the root.
 From this point (B)
a trench ran to the east in a straight line,
varying between 5 and 10 inches both in depth and width. These numbers
shrank as the trench started branching about 30 feet away (C).
 Soil was randomly
tossed out in clumps and chunks, as much as 8 feet.
Roots along the path were charred as seen above. The main trench went
to the corner of an in-ground crypt and traveled underneath the lid
before exiting. Just short of the exit it blew off a small piece of
cement into multiple fragments (D), and then continued a few more feet
to the base of a small oak tree next to a metal fence (E). Here it took
a 90 degree turn to run along the fence, leaving another small trench,
before disappearing several feet later. Adjacent to the fence I saw a
small hole under the metal leg of a bench (F). This may have been
caused by smaller and more winding branches that left the main trench
(C) as much as 30 feet toward adjacent graves.
 As a group the
various paths mimicked the forking pattern seen in cloud to ground
lightning bolts.
 In retracing my steps I was even more surprised to spot smaller portions of a trench on the opposite side of the tall oak tree, in the same straight line as the main gash but apparently traveling in the other direction (B to G).  Family members who stopped by the cemetery while I was there said they had seen a lot of lightning a few days earlier with little rain. I asked if there were underground wires or pipes and they didn't think so. One person did say there once was a house adjacent to the cemetery but it had been torn down years ago. Lightning trenches have been documented before and they are probably more common than not but this one was remarkably straight and large. The mystery is what, if anything was beneath the ground to channel the stroke in a straight line through the tree base. Usual suspects are wires, pipes, old fence lines, mineral deposits, and streams. Ron Holle, a meteorological consultant with Vaisala says none of these may be the cause. In similar cases he found that there was nothing in-ground that channeled the electricity. "Lightning typically radiates outward in several arcs from the strike point." It's possible that there were other less-visible trenches. Ron cautions, "There is no reliable way to project where the current will go across the ground in these arcs. There is no way to safely predict where one can be safe near a tree.” The second mystery is what the current did as it passed through the graves. Your guess is as good as mine but I was not about to start digging in this cemetery! You can see streaming video of this story at http://wkrg.com/weather/article/lightning_trench/5080/ If the link is broken try http://www.wkrg.com using keyword: trench. |