Friday, August 25, 2006

I know the weather has been weird around here, but dangerous ground-to-ground lightning? That's just too much.

We've had the humid part of the Dog Days here, but it' s been more rain than heat lately. It's just been one long series of soggy doggie days.

I was out in the open countryside, driving to work and dodging thunderstorms this morning, watching lightning in the distance and wondering about the liquid LP gas truck in front of me. What are those guys supposed to do in a thunderstorm? Pull over and run like hell? Or just pray, and keep on truckin'? What am I supposed to do?

Suddenly my reverie was interrupted by the alarmed voice of the announcer reading off the latest in an endless stream of stunningly obvious weather alerts -- thunderstorms (no kidding), high winds, potential hail, and then, (get this) "dangerous ground to ground lightning."

Ground to ground lightning? Were Mother Nature's neurons misfiring? Short-circuiting? Something didn't seem right. After all, the ground and the clouds have opposite electrical charges in a storm. That's what makes lightning jump from clouds to ground, or vice versa.

But you never know. They're discovering new stuff all the time. You can't be too careful, and I kept a sharp eye out for lightning bolts that a suddenly malign Mother Nature might hurl at me from silos, barns and cornfields.

As soon as I got to the office, I did what any modern person does. I conducted a quick, superficial Internet search. I'm happy to relate the results of my research here:

You can relax. There ain't no such thing. The term "ground to ground lightning" scarcely exists on the Internet, and when it does, it's almost always attached to this photo. It's an Earth Science Picture of the Day posted last month and endlessly reposted. (You can click backwards and forwards to see other neat pictures of the day.) It was photographed in southern France on May 10 by Vincent Jacques. And as the caption explains, it's not really "ground to ground" lightning.
Since the ground is charged opposite that of a cloud base, and will not discharge to itself, it's likely that this picture is showing two cloud-to-ground strokes. Perspective makes it appear as though a single lightning bolt is arching above the hill top.
But then what about the weather alert? I was sure I heard it correctly as "ground to ground lightning."

Fortunately, I receive the same weather alerts in my email and a bunch was waiting for me when I got to the office (the other day, 30 had piled up overnight -- that's the sort of weather we've been having).

And there it was -- exactly the same wording, except for one word change: "dangerous cloud to ground lightning." I even checked some of the other alerts, and none of them said "ground to ground."

So the weather guy must be been flipping through the Earth Science Picture of the Day recently, saw the picture, retained the term (maybe he never read the caption) and then misread the weather alert as a result. Mystery solved.


Ookami Snow said...

That is crazy...

I have never heard of that before.

mog said...

Pretty picture thou, seen a few that looked a lot like that but without the camera handy.

BlueFox said...

Cool picture - but when I saw it I also thought that it might be two cloud to ground lightning which cam fro the same spot. The only other possibility I though of - bear with me here - is it possible to have a ground to cloud and as it get's there changes from cloud back to ground? Just a thought!