Is Heat Lightning harmful?

Please define “heat lightning”. Then I’d be more than happy to answer your question. I have found that people have different definitions of this term. Do you mean lightning that occurs with no thunder? Or do you mean something else?

Why all the lightening questions?

@Les: Heat lightning as in lightning that happens after hot summer days.

@augustlan: Just because I like lightning =]

OK, well, that doesn’t really help me very much. I’ll answer my own question, then. If what you mean is lightning occurring with no thunder, then the answer is: yes, it is harmful, but probably not to you at that moment. If you ever see flashes of light far on the horizon (what people refer to as ‘heat lightning’), you often do not hear thunder associated with these flashes. Seems counter intuitive, since both are one in the same, right? Well, the reason there is no sound is because the storm is simply too far away to hear the thunder. Next time you’re in the middle of a terrible storm, count the seconds in between the flash and the bang (called ‘Flash to Bang Count’). Then divide by 5. So let’s say you counted 10 seconds. Divide be 5, that gives you 2. This is (very roughly!) how far away the storm is from you in miles. What you should notice is that the farther away the storm is, the quieter the thunder is. So it goes to imagine that there is some distance at which being able to discern the sound of thunder would be impossible (maybe about 10 miles or so? Not sure.)

Bottom line: All lightning is, or has the potential to be, harmful. You just have to be careful.. My rule of thumb is if I can see it, it is too close.

Only when something is struck by it, such as a human being.

@Les, then where does “dry lightning” fall in to the mix?

I’d imagine ‘dry’ lightning is when there is no rain with the lightning. Just for the sake of clarity, in meteorology, we don’t really distinguish between lightning so much as the general public does. But it’s OK, I realize there are regional ‘slang’ terms for these things. Now, back to your question. All lightning occurs in thunderstorms, right? And all thunderstorms have rain. Now, sometimes thunderstorms can have rain that doesn’t reach the ground; it’s called virga. And what is happening is the rain is evaporating before it hits the ground. Happens a lot in deserts, but can happen anywhere, really. So what you would see is lighting with no accompanying rain, or ‘dry lightning’.

And @the mods: Re-reading my post in the live preview is confusing! It be not Pirate Day on the other side of the Date Line any longer, says I.

@Les; I was asking because I’d never heard of it until all of the fires we had in Northern California this summer. The media started saying that most of them were caused by dry lightning. Lightning storms are fairly rare in this area, in comparison to other places, and the firs closest our home did start when there was lightning but no rain falling on the ground here, so that must be what they mean. I wish they’d just call it by the technical name. Then I would have googled it and figured it out. Or they could have just explained it on the news.

No. It is too far away to be of harm.