by Nelson Holmes
Having spent most of my life in Southern California I got used to weather that is placid and predictable. A few drops of rain and Angelinos start working the apocalyptic math. So, Colorado, and the array of meteorological changes that can be experienced in the course of a day, has been, for me, a source of joy and wonder. And nothing stimulates that wee core of primitive grey-matter at the base of my cortex like lightning.
Our primal fascination with lightning might have to do with learning that fire might be harvested at the site of a strike. Or, maybe the fear and awe were products of finding the occasional mammoth or family member smoldering under a threatening sky. Whatever the reason, I’m drawn to the bolts like a moth to a flame. Summer afternoons often find me staring aloft; mouth agape, with a strange, glazed-over, cast to my eyes. What’s not to enjoy? Anything traveling at 60,000 miles per second with a temperature of 55,000 degrees is, beyond any question, the essence of entertainment. Add the varied tracks, changeable color (I’ve seen lavender bolts with a sober eye) and the threat of mortal danger to keep the adrenal gland clenched, and you can cancel the cable. Lightning can form between clouds or between clouds and the ground; and the clouds can be dust, volcanic fumes or the smoke from a forest fire. Typically, lightning forms as ice crystals within the thunderhead cause a forcible division of positive and negative charges within the cloud. The resulting imbalance of electric charge creates a discharge (lightning) which superheats the air, causing rapid expansion and the shockwave that we experience as thunder. If this pack of variables doesn’t pique your interest, there are different types. Ribbon lightning is caused when high wind forces the return stroke of the bolt to track away from the initial strike, creating a ribbon effect. Bead lightning is when the stroke breaks into sections that glow and linger longer than normal. And then there is the mysterious, but amply chronicled, ball lightning, which can last many seconds and can range from the size of a pea to that of a demolition ball. For real students of lightning phenomena the coolest stuff happens between the stratosphere and the thermosphere where the elves (Emissions of Light and Very Low Frequency Perturbations from Electromagnetic Pulse Sources) sprites and blue-jets occur. These we’ll leave to the aficionados.
My personal moment of lightning induced, pants-wetting, glee came on a spring afternoon. I heard the booms that announce show time and went out to my field to watch. The thunderhead above was particularly active and the, cloud to ground, bolts were frequent and dramatic. I took up my station, looking towards the darkest part of the cloud above when an enormous bolt struck about half a mile before me. The lightning then split into two horizontal bolts that raced at what seemed just a short distance above, and parallel to, the ground. I stood at the mouth of a fiery “V” as the bolts flew out beyond me on both sides. After a moment’s nervous laughter, I fled to my couch to watch the rest of the show through a window. By the way, the basic rule: if you can hear the thunder, you’re in danger. If you want to know just how much danger, count the seconds between the strike and the thunder and divide by five and you’ll have an idea how many miles away the strike was.