Thunderstorm and lightning

[Screwdriver]

Very (very) frightning. So it was getting closer and closer, huge hailstorm so I whipped the phone out to record a vid.

Massive flash bang, so instant it was obvious it was close. Looking back at the vid, it was two doors down, end of my garden. So I wander over to see what got hit. Big crowd, fire engines, no smoke of fire thank goodness.

Turns out, it hit a roof, knocked a hole in it, took out all their electrics. Later on I discover the whole of Ealing (Vodafone) lost internet. I am cat sitting currently so using a neighbours internet. I waited while the unfortunate roofless couple spoke with a fireman, then jumped in: “Hi was it your house that got hit?” “I have it on video…”

Why the fuss? Well that’s pretty unusual but the really interesting bit is, there appears to be an EMP. The video has a distinct dropout or flash frame, just before the pretty plasma fork we call lightning. If I had internet, you’d be watching the video on YouTube and I’d know if this really was an EMP.

Just got internet and posting here before I look it up, see if that is a common feature of close lightning. Pretty sure it must be, only question being how rare is it to detect during a strike…

 

[Screwdriver]

Grok is talking about a “stepped leader” prior to a strike but I am not convinced. I think this was a huge static charge that disrupted my iPhones video recording.

Be interesting to hear what people make of the video artefact if I can ever edit and upload it.

 

[dobbslc]

Don't the leaders come up from the ground to meet the main strike?

 

[Seadog]

Where you have current flow you have an associated magnetic field, so yes, I reckon with a few million amps there's a very high chance of an EMP.

 

[Screwdriver]

Don't the leaders come up from the ground to meet the main strike?

Yes, we can blame Benjamin Franklin for guessing the direction of flow wrong too. Conventional current flows from positive to negative. So far so good but sadly after Franklin guessed the direction with some charged amber, it turned out that the "fluid" he was describing was composed of electrons -and they flow the other way!

Does my head in tbh. Electrons really ought to be positive! By the same token, Pi really ought to be 6.282 etc. (long story).

Anyhoo, the actual flow of particles, electrons, starts in the clouds which are therefore (sadly) negative. It starts with the so called "stepped leader" a gradual ramping up of static charge then suddenly, a massive pulse of positive charge rises up from the earth forming the lightning bolt (aka a plasma where all of the electons go missing from matter).

For all the electronics guys out there and especially those of us who suffered the indignity of semiconductor theory while trying to remember the electrons run "backwards", Franklin is to blame. Should have cut our losses and made electrons positive by convention because (maybe it's just me) having the "conventional current the complete opposite of your intuitive understanding of how things ought to work is a real headbender.

Same is true of using a ratio of a diameter instead of the more logically obvious radius, to determine Pi.

Where was I. Oh yeah. I'm back home and internet is back on. Watch this space for a YouTube vid of this "dropped frame/corrupt frame/ EMP" thing. It's less exciting than it sounds. Largely because the noise was so tremendous it made the event notable. The iPhone missed the drama. In fairness, no audio device in the world is going to replicate a thunderclap that goes off right by your ear. The strange "flash frame" looks just like a typical pink box of missing data. Maybe some internet gurus will be able to pick apart the video to get more details....

 

[Screwdriver]

Where you have current flow you have an associated magnetic field, so yes, I reckon with a few million amps there's a very high chance of an EMP.

Yes, I think so too. Even the description of "stepped leader" being a sort of static charge which suddenly collapses sounds like a good enough description of an electomagnetic pulse.

 

[Screwdriver]

 

[Seadog]

I was in Dartmouth on a chartered yacht many years back. We were considering heading off, but the weather was looking decidedly iffy, so we decided to hang around for a while.
About 10 minutes later it went very dark to seaward and a lightning strike hit the sea outside the entrance, probably near where we would have been had we left, with a nice pointy aluminium thing poking skywards

 

[500e]

We got hit or very close took all the B&G electronics out and the radio, all a smoking heap, all wiring in mast shot as well.
Comming from France to Uk

 

[Robotstar5]

I used to camp just outside Barmouth a lot where the campsite looked out over the bay, one spring we watched the sky over the bay getting dark so made a mug of tea and sat in the car to watch, first the sea turned dark green then the lightning started out at sea and slowly moved towards land and the downpour swept across the campsite, would have been good to video it on the phone, but they hadn't been invented in the 70's

 

[DAPPH]

i gather that all strikes have an EMP , the one that slapped us was from a strike 320 mtrs away , confirmed by a group of highly credible amateur specialists who supply an international org with data that is then run through a supercomputer. The generated EMF on the power lines burnt out anything plugged in & the EMP took out quite a few things that were not
Using their evidence to support our insurance claim the insurers sent a man round who confirmed the claim and authorised an almost £6 k settlement .

 

[Keith 66]

Some years ago we had a really good thunderstorm & there was a close strike probably with a hundred yards, flash & bang were all but instantaneous.
Next morning went to the workshop, all power was dead. Had to call the sparks out. Turned out the main RCD trip was completely fried, its coil fused into a solid lump. So yes an emp goes with lightning!

 

[Maker]

Same is true of using a ratio of a diameter instead of the more logically obvious radius, to determine Pi.

I disagree with that one, for all the factors of 2 you need to work with Pi, you'd have as many factors of 0.5 to work with Tau.

 

[DAPPH]

Some years ago we had a really good thunderstorm & there was a close strike probably with a hundred yards, flash & bang were all but instantaneous.
Next morning went to the workshop, all power was dead. Had to call the sparks out. Turned out the main RCD trip was completely fried, its coil fused into a solid lump. So yes an emp goes with lightning!

So does brown trousers .

At the old railway Keepers Cottage where we lived , our hair suddenly went on end , a massive x ray style flash & an earth shattering bang saw the remains of slag iron track bed smouldering and an awful stink of sulphur coming from the mark . Both of us unable to hear for a few minutes .
The strike hit was about 15 feet from the main track side window
The telephone jumped off its cradle several inches , it was four or so minutes before we could hear properly & a good half hour before our heart beats had steadied to normal.

 

[Screwdriver]

Many years ago I was working deep in the Sahara laying out a line of marker flags. These were foot long steel wire and plastic flags. Hot cloudy day with interesting cloud cover though not especially dark.

So it was hot and dry and I noticed a tingle through the wire flag through my bare fingers. If I raised it up, the tingle became stronger. I tested that a few times because it was an interesting phenomena until it suddenly occurred to me what was happening!

I ran for the Landrover where I could hear the whip aerial also fizzing and humming, jumped in anyway. Seconds later there was a massive flashbang probably no more than a few metres from the door. I wish I'd had the nerve to pick up the glassy puck left in the sand but decided discretion was the better part of valour and foxtrot oscar sharpish...

 

[Erie Fred]

Our weather people show lightening strikes on a map, with a + and others with a -.

Lightning Types

Descriptions of various types of lightning, from the NOAA National Severe Storms Laboratory.

www.nssl.noaa.gov

 

[Screwdriver]

Science is awesome isn't it?

Who knew just how complicated this phenomena could be...

 

[Martin-Sy]

Our weather people show lightening strikes on a map, with a + and others with a -.

Yes, our Met Office does too.

Met Office Lightning Map

Here is the map of the first few strikes from 22nd March '25 in the London area.

There were a lot more strikes later, but the history is only available for a few days I think.

The EMP would have an instantaneous (well subject to the speed of electromagnetic propagation) effect on the camera electronics, but the image I suspect would be delayed by the interface to the image sensor (probably serial data), video frame rate and processing. This might account for the glitch being shown in the video before the actual lightning.

 

[Screwdriver]

The EMP would have an instantaneous (well subject to the speed of electromagnetic propagation) effect on the camera electronics, but the image I suspect would be delayed by the interface to the image sensor (probably serial data), video frame rate and processing. This might account for the glitch being shown in the video before the actual lightning.

Spoilsport!

I knew you were right the moment I saw this. While the camera is delayed, busy sorting out the feed from the sensor, lightning bolt goes off and disrupts the encoding while the electronics are still sorting out the frames it captured some moments ago. It is still an EMP of course but not one displaced (so much) from the lightning bolt itself.

 

[fizzy]

Yes, our Met Office does too.

Met Office Lightning Map

Here is the map of the first few strikes from 22nd March '25 in the London area.

View attachment 489444

There were a lot more strikes later, but the history is only available for a few days I think.

The EMP would have an instantaneous (well subject to the speed of electromagnetic propagation) effect on the camera electronics, but the image I suspect would be delayed by the interface to the image sensor (probably serial data), video frame rate and processing. This might account for the glitch being shown in the video before the actual lightning.

I prefer this one - shows the whole World!

Real Time Lightning Map

See lightning strikes in real time across the planet. Free access to maps of former thunderstorms. By Blitzortung.org and contributors.

www.lightningmaps.org