When Lightning Strikes 285
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."
Lightning/Tornados or Earthquakes (Score:1, Interesting)
Umm.. the constant threat of earthquakes is nothing to sneeze at... while not as loud as thunder/lightning it's sure can be a wild ride.
http://quake.usgs.gov/recenteqs/latest.htm
Side effects (Score:3, Interesting)
he was in his pool ans could hear thunder in the distance so he throught he should probably get out, but as the cloud got closer the surface of the pool started to "boil". The huge negative chage in the cloud induced an equal positive charge in the ground underneath it. As this positive charge was attracted to the cloud it made ions in the water making it boil. After pondering that for a minute he jumped ou tof the pool so as not to be killed.
Watching lightening...up close (Score:4, Interesting)
Absolutely breathtaking.
Re:Watching lightening...up close (Score:3, Interesting)
Absolutely breathtaking.
I completely agree. We used to spend a lot of time along the Colorado River (Mead and Havasu). You wake up and start with a beautiful, blue clear sky. As the day goes on you can see the clouds forming and growing. By 4 o'clock in the afternoon, the high winds pick up and continue until early in the morning, along with the constant lightening. Definitely an impressive sight.
lightning.. (Score:3, Interesting)
I've never been directly struck by lightning, but I have been "zapped" i guess you can say, by some sort of mild electric shock when a big bolt hit right near my apartment complex.
I ran upstairs to the 3rd floor, to shut a window because it had been raining.. I go to close the window, i'm standing on wet carpet (the whole room is practically soaked) and suddenly BLAM. Big lightning strike, and I got shocked. It almost felt like my whole body was doing a tongue test on those square 9v batteries. Probably the closest i've ever come to being struck.
Has this happened to anyone else? I had previously believed that one could only get struck or zapped by lightning outside of a house.
Re:NLDN (Score:5, Interesting)
And then there's Roy Sullivan. A quick google [about.com] turned this up:
Roy Cleveland Sullivan was a Forest Ranger in Virginia who had an incredible attraction to lightning... or rather it had an attraction to him. Over his 36-year career as a ranger, Sullivan was struck by lightning seven times - and survived each jolt, but not unscathed. When struck for the first time in 1942, he suffered the loss of a nail on his big toe. Twenty-seven years passed before he was struck again, this time by a bolt that singed his eyebrows off. The next year, in 1970, another strike burned Sullivan's left shoulder. Now it looked as though lightning had it out for poor Roy, and people were starting to call him The Human Lightning Rod. He didn't disappoint them. Lightning zapped him again in 1972, setting his hair on fire and convincing him to keep a container of water in his car, just in case. The water came in handy in 1973 when, seemly just to taunt Sullivan, a low-hanging cloud shot a bolt of lightning at his head, blasting him out of his car, setting his hair on fire and knocking off a shoe. The sixth strike in 1976 injured his ankle, and the seventh strike in 1977, got him when he was fishing, and put him in the hospital for treatment of chest and stomach burns. Lightning may not have been able to kill Roy Sullivan, but perhaps the threat of it did. He took his own life in 1983. Two of his lightning-singed ranger hats are on display at Guinness World Exhibit Halls.
Something smells like aluminum... (Score:3, Interesting)
I think this will be the season for antennae and wireless shops around the US. With the growing WAN's around the place, and the endless similarity between a lightning rod and those antennae... Ouch!
Fun to watch but expensive to reproduce...
Re:Watching lightening...up close (Score:5, Interesting)
Until they tore it down in '98 or '99, New Mexico Tech used to have a lightning observatory right in the middle of campus, part of the legacy of E.J. Workman; it was actually an air traffic control tower, with a full 360-degree view. (Workman was an interesting character himself, having been sent down to Socorro from University of New Mexico to work on the "second most important" technological achievement of WWII, the proximity fuze, at what later became the explosives research and test facility at New Mexico Tech).
But, anyway- New Mexico has a very high density of lightning, second only to parts of FL (which has its own lightning research center). From firsthand experience, I can state that the size and duration of the strokes can be extremely powerful; one night I was woken up by a particularly powerful one that set off a number of car alarms. There was no storm with no rain before or after- it was as if one of the explosives bunkers had detonated up on the Hill at EMRTC.
Parts of eastern New Mexico get it even harder. There has to be something about the magnitude of the storms, and maybe the flatness of the land, that forms a particularly large discharge. A good New Mexican frog-strangler is something to behold.
Re:As someone who forecasts the weather... (Score:3, Interesting)
Have a look at this [noaa.gov], for example.
Unpredictable (Score:4, Interesting)
Re:lightning.. (Score:2, Interesting)
"Can I get struck by lightning when I'm indoors?" [howstuffworks.com]
NWS Lightning Safety: Indoors [noaa.gov]
-Mikey P
Misc... (Score:1, Interesting)
Also, there are different types of lightning & static activity - Tesla seemed to be the master during his lifetime. One of the most baffling types of static|lightning activity is ball lighting. There have been stories for a long, long time beyond FOAF|UL describing a small globe of what appears to be lightning in an orb, having appeared out of nowhere, moving about without a pattern, then disappearing as mysteriously. IIRC, most of the reports involve aircraft. Tesla demonstrated great prowess in creating them, controlling them, and destroying them, to the bewilderment of all. And for all who thought he was a crackpot while he was alive (including the gov't), why did they pack up all of his belongings when he died and send them off to parts unknown?
Weather (Score:2, Interesting)
oh let me count the lightning stories... (Score:5, Interesting)
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...
Re:Unpredictable (Score:3, Interesting)
Ugh. You know how they talk about how games desensitize people? I've been playing Unreal Tournament 04 way too much over the last week. One of the weapons that I've grown to love is the Lightning gun. It fires a bolt of lightning and *zaap*. I love sniping with it.
Despite really enjoying zapping people with this game, reading that somebody you know (or your wife knows...) died with it really made my heart sink.
I hope I'm not being disrespectful. That's not the intent... I just noticed... Ya know?
Re:Harnessing the power (Score:5, Interesting)
When we in the University of Florida lightning research group [ufl.edu] 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.
just a few weeks ago (Score:5, Interesting)
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 [wvlightning.com], 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.
Re:Something smells like aluminum... (Score:3, Interesting)
YDI had built a all-in-one antenna that had the Ethernet gear and transcever all built into the antenna that gave me such concern that i had to make direct contact with the manufacture to see what sort of lightning suppression was available. So to my surprise and distress, he admitted that they had managed to get just into production a suppressor for the antenna unit. And this was for a unit that had been in production for over 2 years!
Well, with that said, i simply nodded and used the time-tested method of instructing the clients to unplug whenever mum nature got ugly, or was planning to.
Walter De Maria: Lightning Field (Score:2, Interesting)
Lightning kills cows (Score:2, Interesting)
Humans, on the other hand, don't have as much of a problem, because their feet are so close together.
Re:Watching lightening...up close (Score:1, Interesting)
1rst hand experience (Score:5, Interesting)
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.
when it strikes sensitive equipment (Score:5, Interesting)
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.
Re:Harnessing the power (Score:4, Interesting)
We often strike a section of de-energized power line, with a (nominal) impedance of 400 ohms. That translates into peak voltage of 10 megavolts as a first approximation, and about 250 gigawatts. But, since the peak duration is no more than a couple of microseconds, that's about 500 kilowatt-seconds, and 138 watt-hours - less than a single kilowatt-hour.
Er - what do you do, to consider 25 kA "not much current"? Just wondering...
Im guess I am lucky. (Score:3, Interesting)
Re:FffiiiiiZZZAP! (Score:1, Interesting)
Re:oh let me count the lightning stories... (Score:4, Interesting)
why does that bother you?
If you had a single voltage source, and 4 resistors in parallel, would you not get current flow through all 4?
What if one was a million times as resistive as the others?
Re:Lightning kills cows (Score:2, Interesting)
Re:lightning.. (Score:5, Interesting)
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.
Re:FffiiiiiZZZAP! (Score:4, Interesting)
Nasty Lightning Strike With Photo Gallery (Score:5, Interesting)
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 [austinwaldorf.org] 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 !!!
Re:lightning.. (Score:2, Interesting)
Re:Weather (Score:2, Interesting)
I was going to mod this, but I thought I should reply instead. I call BS on the claim you could see the stars through the cloud breaks. I don't know what you were looking at, but it wouldn't have been the stars unless the storm clouds were dense enough and thick enough to extend all the way through the atmosphere to mitigate the effect of the atmosphere in distributing light. This is the same reason why you can't see stars when looking up through a long chimney / mine shaft / whatever during the day.
Sprites (Score:3, Interesting)
Here is a pic [nasa.gov] of a sprite.
This is linked to in a longish article [nasa.gov]. See under Recent Developments.
Re:Harnessing the power (Score:3, Interesting)
Our rockets themselves aren't that expensive, truthfully. And we can usually reuse the rocket proper, we just load a new motor in it. Those are cheap. What's expensive is the spool of wire attached to the rocket. You'd think that getting 700 m of 32 ga wire wrapped on a spool would be cheap, but to get a spool wrapped with 32 ga Kevlar-reinforced wire which will spool off cleanly every time is, in fact, a non-trivial task. That's where most of the $500 figure comes from. That DOESN'T include the costs of site maintenance, personnel, range safety, etc.
The typical successful trigger occurs at something between 300 m and 700 m here in Florida. It may be different elsewhere, where the clouds are higher.
Lightning flashes HAVE been triggered with large lasers. But we don't have one. We could probably get one, if we could find someone to fund the purchase, but then the amortized cost per flash would probably (yeah, I'm just guessing) exceed the cost of the rockets we use now.
Most of my class notes are pretty well encapsulated in the book my profs wrote, Lightning: Physics and Effects by Rakov and Uman. I imagine Amazon has it, but it's real spendy - I don't even own a copy. However, it's pretty much a definitive and comprehensive treatment of the subject. The bibliography alone is worth the price.
E field (Score:3, Interesting)
That's also why you should NOT lie down on the ground to avoid a strike - instead, you should "become a basketball with feet" - curl up into a ball and balance on the balls of your feet, with your feet as close together as possible (if your balance isn't good enough, then put your feet flat). That way, if a strike hits close to your, the potential across the parts of you in contact with the ground will be at a minimum.
That's also why equipment connected to radio towers should, ideally, be in a Faraday cage (a closed conductive container) - an E field will not penetrate a (perfect) Faraday cage, and will remain on the outside. (Of course, that "perfect" bit is the hard bit, so some field will leak inside, but nowhere near as much as without.)
And as a previous poster pointed out, it is the fact that most cars are pretty good Faraday cages that protects you from lightning in a car, not the rubber tires - the lightning jumped an air gap of several hundred metere, what makes you think a few centimeters of rubber are going to stop it?
Of course, if you are in a modern plastic car....
Even worse, imagine taking a strike in a Prius or other electric/hybrid electric car with a significant amount of battery....
Re:oh let me count the lightning stories... (Score:3, Interesting)
Lightning had struck the outside light at the corner of this house, and had blown the insulation off the wire. It had smashed like toffee, almost like it had been frozen in liquid nitrogen and hit with a hammer.
An office I used to do IT stuff for got hit by lightning, and it vapourised the copper inside a 5-foot length of network cable. There was just this length of thin ethernet cable that looked... just *wrong*. The braid had been "sputtered" onto the inside of the PVC jacket!
Re:Unpredictable (Score:2, Interesting)
Planes Hit By Lightning (Score:3, Interesting)
Another amazing video is of a plane getting hit by lightning at a Japanese airport--check it here [noaa.gov].
Bottom line: planes can be just like a big hydrometeor from lightning's perspective.