Was the building struck by lightning?

[Richard Williams]

Hi,

I would really appreciate any answers from those with knowledge about lightning, because something odd happened the other day.

Trying to get away from the permanently cold conditions of the UK I went to Dubai, UAE for a few days to get heat and sunshine. However, on the day I planned to go up the Burj Khalifa, which is 2,700ft tall, we had some bad weather and storms, which I guess is a bonus for someone like me.

Something really odd happened - when I went out onto the observation deck (1,800ft) there was a bright blue flash, and less than a second later a not-very-loud ripping sound. I expected a big clap of thunder but there was none. I actually happened to be recording video on my camera at the time, and it is not even very obvious. The flash i just about picked up, and the sound is a bit obscured by the sound of the wind.

Given the short time from the flash and the crack sound, it seems lightning must have been very close, but there was no big clap of thunder, just the brief tearing sound. I've been near close CG's before and they always had a huge boom of thunder.

So what is happening here? Was the building actually hit by lightning, and would it really be that "quiet" up close?

This is the video link

 

[Jeff Duda]

That is pretty interesting. Sure seems like it could've been lightning. I think that is physically sensible considering the propagation of sound waves from a bolt of lightning. Each point on the channel is a point source for thunder. The character of thunder depends on the geometry of the bolt and the characteristics of the intervening medium (i.e., air). In a situation where you're generally well above the surface like in a huge tower like that, I think it's possible that a nearby CG hit such that the point of contact was between your elevation and the ground and some of the sound waves destructively interfered, which manifests as little to no sound.

 

[Dan Robinson]

Sounds like a lightning leader ("streamer") or a weak upward lightning discharge. Those produce thunder that sounds just like that. I've witnessed this many times. Here's an example from the OKC tower farm in May of 2007 - upward leaders initiated from five of the towers in response to an in-cloud discharge above them.

Here's the still image (slide film) taken at the same time:

 

[Richard Williams]

Hi,

Thanks for your replies.

Yes Dan I think you are right, I played back the longer version of the video and a few seconds later (not on the short vid) there is a louder rumble of more normal thunder which sounds like it is from an IC discharge in the clouds. So then the one seen in the short video must have been an upwards leader connecting with the unseen IC discharge I guess?

 

[Ben Holcomb]

Looks like the video was shot from At the top outside on the observation deck, which is far from 'at the top' and more just about 70% of the way up the tower. The distance to the top coupled with Dan's and Jeff's comments make me think it was probably lightning.