Measuring the thickness of a lightning bolt

By Kevin Ambrose

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A lightning bolt blew a thin strip of bark from this red oak tree, starting at the top of the tree all the way down to its base. The sap and moisture that was under the tree's bark boiled with the heat of the lightning bolt, causing the bark to literally explode off the tree in long, thin strips. The bark strips were scattered on the ground, up to 50 feet away from the tree.

I was on a golf outing several years ago when my foursome encountered an area below the tee box that was strewn with thin strips of bark. I thought it was very odd for bark to be laying on a recently mowed section of grass and I immediately guessed a nearby tree had been struck by lightning during a thunderstorm the previous night. I persuaded my fellow golfers to help me search for the tree, and it didn't take us long to find the source of the bark.

The tree had indeed been struck by lightning and thin strips of bark had blown off the tree, from the top of the tree to its base, in spiraling patterns. I took out my camera and photographed the scene. I also saved a couple pieces of the bark.

Keep reading for more photos and to find out the thickness of a lightning bolt...



Strips of bark lay scattered on the ground in all directions from the tree. The bark was blown off the tree by a lightning strike.

I've read that the diameter of a lightning bolt is about the thickness of a pencil up to the diameter of a silver dollar. I wondered how a lightning bolt's diameter was measured, or even estimated. After seeing the result of a tree struck by lightning, I can see how analyzing the burn marks and the damage to the tree and bark is one way to estimate the thickness, or diameter, of a lightning bolt.

After analyzing the tree and bark in my photos, I'd estimate this bolt was less than one inch in diameter. It may have even been less than 0.5", if the burn marks extend past the boundary of the bolt. Regardless of the exact diameter, a lightning bolt is a very thin, but very powerful force of nature.



An analysis of the burn marks on the underside of the bark shows the bolt was probably less than an inch in diameter.



The lightning bolt spiraled around the trunk of the tree from top to bottom, blowing off strips of bark in all directions.