Lightning strikes the Eiffel Tower
It seems to me that every morning when I check my computer weather prediction, it shows a cloud with a lightning stroke descending from it. But then another day of oppressive heat passes when we have at best a brief shower.
That's just as well. Lightning is one of those marvels of nature that is beautiful to watch from a distance, but that poses a serious threat when you are exposed.
I've had enough personal experiences with lightning to make me wary of it. And the data bears me out. Over the past 30 years 58 people have been killed each year by lightning. That's more than other averages: 57 annual deaths by tornadoes and 48 by hurricanes.
Easily my scariest experience was years ago when I was a school football coach. We were midway through the last quarter of a game, when suddenly thunder pealed and instantaneously a lightning stroke hit nearby. Standing on the sidelines, I could feel the electricity run up my legs. I immediately walked out on the field and asked the referee to stop the game. He agreed and we herded hundreds of players and spectators into the nearby school locker room and hallways. What was so surprising about that episode was the fact that when it happened it wasn't raining and the sun was out. By the time we got most people inside, however, it was teeming down so hard I felt as though I was underwater.
More recently, I was aboard an airplane in Dallas already on the runway waiting to fly to New York City. Our pilot hoped to beat an approaching storm, but then we could see it blowing tumbleweed down the airstrip. We sat and sat, grumbling about the delay until finally we were informed that we would take off and fly around the storm.
First, however, we had to fly out of the storm. As we rose through the clouds, I looked out and saw lightning flickering over the airplane's wings. I began to wonder if our grumbling hadn't been unfair and we should instead have urged the pilot to delay still further. Needless to say we made it okay, but after experiencing through some violent turbulence.
Finally, one day I stood looking out the window of our house during a rainstorm when a bolt hit the telephone transformer behind our house. It was like a bomb exploding, but thankfully without the attendant concussion. Linemen had to climb that pole to replace the transformer while the storm still raged. I haven't complained about electric downtimes since then.
What is lightning anyway? According to Canadian science writer, Edward Willett, it is "a massive but short-lived electrical discharge in the atmosphere, usually several kilometers long. Lightning arises because of a charge separation in a cloud. A charge separation just means that there are more electrons in one place than another. Cloud-to-ground lightning occurs when there are lots of free electrons in the base of the cloud. These electrons are discharged in what is called a stepped leader: 'stepped' because it descends from the cloud in discrete steps, each about 50 meters long (which is what gives lightning its jagged appearance), and 'leader' because that’s what it is - the precursor for the main bolt.
“Since electrons are negatively charged, this stepped leader has a very strong negative charge. When it gets within 100 meters or less of the positively charged ground, another leader moves up to meet it, often through handy protruding objects like buildings, trees and golfers. What we think is the main stroke of lightning is actually the return stroke, which propagates upward from the ground along the path formed by the leader and the stepped leader."
Okay, we know what it is. What should we do in an electric storm. The National Oceanic and Atmospheric Administration suggests the following:
(1) Monitor weather conditions and postpone outings if a lightning storm is predicted.
(2) Enter the best available shelter when lightning threatens.
Good shelter includes: substantial buildings and cars with windows closed. If you cannot take advantage of these, seek low ground or a uniform tree height woodlot. Avoid open fields or open water, high ground and solitary trees.-- Gerry Rising