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When Lightning Strikes
ctwxman writes "For most of the United States (sorry West Coast), this is the season for lightning. It is as powerful as it is spectacular to look at. It is destructive too - by itelf or through the hail, straight line winds and tornadoes that often accompany it. As someone who forecasts the weather, I'm often asked about lightning. As you might imagine, there's plenty to see about lightning on the Internet. The conditions necessary and a little bit of the physics behind lightning are explained by Jeff Haby, a meteorologist (one of my professors actually) at Mississippi State University. Once forecasters get a handle on what's going on, they put the word out through the Storm Prediction Center. Regular outlooks are issued by SPC for severe storms. Once those storms rear their ugly heads, they're followed with mesoscale discussions looking at the active areas. The Storm Prediction Center is also the place where Severe Thunderstorm and Tornado Watches are issued and storm related damage reports are compiled. Lots of hobbyists like to track lightning strikes on their own, and there's equipment available to do just that. Getting hit by lightning is never fun, though not always fatal. National Geographic chronicled an amazing story of a lightning strike, and rescue, on Grand Teton."
For a bit of fun, you can check out the National Lightning Detection Network, which shows recent lightning strikes in the USA over the last few hours.
Q: Why did the blonde keep stopping then smile during a
lightning storm?
A: She thought she was getting her picture taken.
The first link is a little scant on details...if you're really interested in lightning I'd recommend this.
The headline is great!
Not really on it's own merits, but I instantly imagined the remarks from when the "story" is posted again in 2 weeks: "When Lightning Strikes Twice"
I know Im going to get modded down for this; but Ive lived in Wa, Tx, Ak and Az; and out of all of them, its (ironically) been in Az where Ive seen lightening the most intensely (longer duration, and more clearly visible) and also the most closely (within blocks of where I live).
Absolutely breathtaking.
As someone who has lost his share of equipment to lightning hits over the years (telephones, one PC, even a CB radio) I love being able to unplug my wireless laptop and feel safe to keep surfing. God bless 802.11b.
LETS DECOMPOSE & ENJOY ASSEMBLING
For most of the United States (sorry West Coast), this is the season for lightning.
Damn. And I had my cable hanging down from the Hill Valley Clock Tower all ready too.
The coolest voice ever.
As someone who forecasts the weather
Sorry, you've lost all credibility right there.
-my other sig is your mom
Don't forget the New Mexico Tech Lightning Mapping System. Here's the link http://ibis.nmt.edu/nmt_lms/
It has some pretty neat images of their lightning mappings. You can see the lightning in 3D, and the precursors to lightning, etc.
Not much info, but there's been some really neat research going on out there. Maybe someone else knows more.
My wife's best friend was killed by lightning in Houston in 2001. A storm had passed though about a half hour before and it appeard to be clearing. She went into the front yard to do some weeding in a flower bed beside the driveway. Her house was in the middle of a bunch of very large pines. They probably had 2 dozen 75-100' pine trees throughout the yard and the entire lot was under the canopy. Not to mention that there were 2 aluminum light poles within 25 yards of where she was struck. Examining the damage afterwards, a tree was struck. The lightning travelled along the tree for about 15 feet and then must have travelled through the air, through her body and into the rebar in the driveway (or reverse that since lightning supposedly travels up). A neighbor began cpr within 2 minutes and they had her to a hospital within 15-20 minutes. They got her heart working again eventually, but never any brain activity. I kinda like to think that she died immediatly. From what I was told, there wasn't any visible damage to her body except for some blood from her nose and mouth (that was third hand since the neighbor wouldn't talk about it).
What you probably experienced was the resulting radio waves that are emitted when the charge from a bolt of lightning enters the ground (though you probably only got a mild version of this).
This is why people are discouraged from "seeking shelter" under large trees during a lightning storm. Not only is the taller object more likely to be struck by lightning, but also the radio waves emitted within a 10-15 ft radius can cause you to go into cardiac arrest. Dangerous stuffs if you're too close to the strike point.
A guy I know put an antenna up in a pine tree, about 70 feet, without a ground wire. Needless to say it got nailed, about 2am while he slept. Detonated the antenna, peeling it into 2ft long, thin strips of fiberglass. Boiled his coax, all the way into his house. Electrofried his radio, and set its power cord on fire. (under his bed, where he was sleeping, setting the carpet on fire) Blew the outlet off the wall. Got into the breaker box and destroyed several breakers, two microwaves, and three color TVs. Finally found ground via the phone entrance box on the outside of the house, which was blown off the house. This was the SECOND time he had been hit, the previous time was the same exact scenario, just not as damaging.
A guy down the block got his ham radio antenna hit, blowing the base of the antenna to pieces. (severing the ground connection in the process, unfortunately) The lightning then took out his coax like det cord, which was laid down under one layer of shingles. This shot the shingles that were laid over the coax right off the house. It then took out his radio, followed the power cord into the electrical system in his house, took out all the appliances in his kitchen, and then went underground to his garage and took out three marine radios that were on charge at the time.
A friend and former co-worker had an employee of his arrive late to work. When asked of the excuse, he said he got his truck struck by lightning on the way in. And boy did he. They never found any of the whip antenna. The base of it, solid brass, was melted like ice cream. Blew out the back sliding windows where the coax came into the cab. Blew the radio to pieces. Finally found ground via front left quarterpanel, which was permanently bowed inward from the sudden heating.
I worked on someone's computer recently, they had pictures on their desktop of a relative's car that was struck while going down the highway. It hit the rear mounted stereo antenna, arced into the body of the car, (creating a 1/2" hole in the metal near the antenna mount) and found ground via ALL FOUR TIRES, arcing across the wheel wells and apparently through the steel belts, flattening all four tires in the process. It also blew out the rear window from the concussion.
My car was struck by lightning while on the road too. Took out the headlights and the windshield wipers, which then started working normally a few hours later. (probably tripped the breakers that those items usually are on instead of fuses)
I have a large ham radio antenna at my house as well, which has been struck at least three times so far, you can count the char marks on it. Thanks goes to a 1/4" solid aluminum ground wire and a 10ft copper water pipe for a ground rod, the lightning has never even scratched my radio, which remains plugged in and cabled up 24/7.
Lastly, if you're ever on a beach and run into a patch of what appears like a cross between pavement and sand, that's where lightning has struck the beach and melted the sand into glass. Really weird effect...
I work for the Department of Redundancy Department.
If you mention one more relative, this will be an observable pattern worth formal inspection. We know lightning strikes trees, but family trees?
Anyone seen my jagged little pill?
It's a nice thought, harnessing the power of lightning. And it's true that there's a really high power output. However, the duration is so short that the total energy, in terms of kilowatt-hours, is typically on the order of US$0.20 - US$0.30 per lightning flash.
When we in the University of Florida lightning research group trigger a lightning flash, we use a $500 rocket to get that US$0.30 worth of electricity. This alone makes the whole process very cost-ineffective. Add to this the fact that there is not a good way to store that much energy that quickly, and you quickly realize that it's simply not practical to try to store lightning energy.
I'll be glad to share more information, if anyone's interested.
Ce n'est pas un vrai mouvement de robot!
There was a flash very big boom, during which a piece of electrical equipment up the street turned into sparks. A moment later, the sky lit up again, this time not white, but blue.
My office is on the forth floor in a not very big town, so I have pretty good view of a lot of it, and it was lit up as bright as the brightest of sunny days. But blue.
I believe I saw a flashover, which occurs when lightning hits something electrical, and the electricty within, which had previously been happy doing its thing, jumps out and follows the lightning bolt's path. This can continue for several seconds after the lightning has stopped.
My girlfriend was there to see this too--in fact, she dropped to her knees and said "that's the scariest thing I've ever seen." And I agree. Lightning is fascinating stuff, and terrifying.
I'm in Sydney, Australia and I just saw a butterfly flapping its wings. Someone on the other side of the world is about to get a tornado on their doorstep.
My own experience with lightning, for the lack of a better word, was simply awesome and I'm glad it wasn't a closer hit. A thunderstorm developed over the neighbouring fields of my parent's farm and slowly made it's way over our fields. It was an extremely hot and humid day, the sudden down pour settled the dust quickly while the temperature dropped several degrees in a few seconds. I watched a lightning bolt strike the ground in the middle of a flat empty field leaving the ground smoking even though it was raining cats & dogs.
I happened to be standing at the patio door: bare foot on a forced-air furnace register (vent) which was effectively well-grounded. The next lightning bolt struck a nearby tree or the house. It didn't really matter where it struck. I could literally feel the charge race through my body and make my hair stand on end. The flash and boom were simultaneous.
A few minutes later we were sitting at the kitchen table. Another close-by strike caused a 6-inch long blue arc that leapt from the electric stove's fuse panel through a stainless pot and grounded out through the stove's element. It also blew out all the lights on that side of the house.
That was by far the scariest storm I have ever experienced.
by pure coincidence I opened my browser to /. while waiting for the voltages to come back up and I see this story up at the top.
Err... no.
There is a great big electric field associated with a nearby channel, and field gradients can result in some really interestingly large voltages to appear across things like the ground.
However, to call these fields radio waves implies that they are oscillatory in nature, which is simply not accurate. I'm a lightning researcher, and in the course of my work I've studied lightning electric fields recorded during close lightning strikes. It's not my personal favorite area of interest, but I know enough to say that "radio waves" is a poor description.
The reason that you don't stand near trees during an electrical storm is because 1) the flash is likely to initiate a side channel which passes from the tree-trunk (radio tower, light pole, bus stop, etc) through you, making you very unhappy; and 2) because the HUGE injection of current into the ground causes the ground itself to "rise" from a nominal 0 volts to several kilo- or even mega-volts, and that voltage falls off as the square of the distance... so that if your two legs are 10 feet and 12 feet respectively from the channel termination point, you might experience a voltage of several kV (or more) between them. This causes a current to flow up one leg and down the other, and makes you (and your goodies, don't ya know) very unhappy. This is worse if you happen to have four legs which CAN'T be placed together, like if you're a cow or horse. Zap!
Ce n'est pas un vrai mouvement de robot!
I concure with this possability, it may not have been boiling (as per reaching an approx. temp. of 100 degrees C (220 F) but may have appeared to be boiling due to the movement described above.
This is similar to how microwaves work. Also Ionization is not just used for nuclear fusion, quick question for you...
Q: If nothing sticks to teflon, how do they get teflon to stick to the pan?
A: They ionize the pan with a positive (+) charge, and ionize the teflon with a negitive (-) charge and it will stick like the opposing ends of two magnets
"Physics class is now over, please read pages 121-320 by next class"
DarkMantle I been bored, so I started a blog.
I have been hit by lightning and it is a surreal experiance, essentialy it goes like this:
A split second before your hit you know something is up, your hair starts to stand on end and you get goosebumps.
Then it hits. You feel torn towards the lightning stream almost as if it attracts you to it. All your bodies muscles and tendons constrict, your fingers tighten so hard your nails cut into the palms of your hands. Its like licking one hell of a 12volt battery.
Then you collapse and pass out for a bit. When you wake up your "exit point" in this case my foot is burning beyond belief, due to the fact that it is quite seriously burnt. Your mouth tastes of copper and you can smell electricity everywhere.
Afterwards your hair stands on end for HOURS and doesn't go down.
At least that is my experiance.
About two weeks ago, during an after-school rehearsal of Macbeth, we heard a sharp clap of thunder as the three witches were reciting "Double, double toil and trouble; Fire burn, and caldron bubble....". We were startled at first yet were quickly amused at its timing. One of the actors emerged from the dressing room quite pale and said he saw a flash of light streak along one of the walls.
After the rehearsal, I returned to the computer lab, sat down at my PC, and noticed that it was powered down... and it wouldn't power up. I wandered into our LAN/Server/Broom/Tool/Ex-Bathroom closet and discovered that 2 servers, 4 PCs, our SDSL router, our 24-port Switch, and the Ethernet port on the motherboard of 10 new PCs were all dead. The PCI NIC in my PC had a crater in it. Our PBX was toast and the 25 and 50-pair phone cables between buildings were severely damaged as well..
If you'd like to see a short Flash-enabled gallery of the destruction, go here As usual, click on a thumbnail to see a larger image.
A company that is no longer in business installed our punch-down blocks, and they grounded the blocks to a faucet attached to a copper pipe. The person who did the plumbing on the building said that the copper pipe does not travel far before it continues its run as a PVC pipe. The cable and punch-down block installer did not use a true power ground with a 6-ft spike in the ground. We did have lightning arresters on the blocks, but I found the one connected to our SDSL line charred on the floor. It got blown off the wall (one million volts, 200,000 Amps coming through!) The surge traveled over our data network, not through the AC power supplies.
I've also been looking at web sites that indicate that there's no conclusive proof that lighting rods are effective deterrents even though they're recommended in many building codes.
Having fun in Austin,
A Chief Technical Agonizer
p.s. We discovered today that the light board in our auditorium also got nailed. It's like "Close Encounters" in there without the tones, but then again, we haven't fully tested the sound board yet. Who knows what we'll find tomorrow !!!