Lightning Damage at GSP Airport
Bryan P. McAvoy
Author's Note: The following report has not been subjected to the scientific peer review process.
On Friday evening, July 28th, a fierce thunderstorm affected central Greenville and Spartanburg Counties. The storm was unusual in that it drifted slowly west, dropping torrential rain (2.97 inches at our office). Hail fell for nearly 30 minutes at the airport, reaching the size of dimes on two occasions. The storm also had nearly continuous cloud-to-ground lightning. In addition to the several trees which were struck at the GSP airport, the main runway was also hit. Lightning blasted an 18 inch diameter hole in the runway, temporarily closing the airport.
Figure 1. A series of four images showing lightning damage to trees at the Greenville - Spartanburg International Airport, caused by a severe thunderstorm on 28 July 2000. From left to right, a tree in the long-term parking lot, along with a close-up of the same tree. Looking up the trunk, the scar caused by the path taken by the lightning along the bark of the tree. Another tree damaged by lightning was just a few feet away. Click on the image to see a larger picture.
The first three pictures are of the same tree. This is a wonderful illustration of how lightning works. The lightning strike followed the conductive, living outer layer of the tree. While bark was knocked off in a 4 or 5 inch width along the path, a much smaller channel was cut in the wood of the tree. The width of an average lightning channel is somewhere between that of a pencil and a human finger. Thus, the deeper gouge in the tree was that of the lightning channel itself!