Car gets struck by lightning - how, and what happens?

[Anaamika]

I ran a search in the forums and couldn't find this anywhere. It is pouring, thundering and raining here, and I could see the lightning striking down as I was driving to work. Which brings me to my questions:

How would a car get struck by lightning? Under what circumstances?
What would happen? Would the car stop dead in its tracks?
What do you do then? How do you get out of the car?
Would your car be damaged or destroyed?
Is there a difference between really new cars (this year), those made about 10 years ago, and 20, and so on?

Thanks - can't help but wonder.

[beowulff]

Originally Posted by Anaamika

I ran a search in the forums and couldn't find this anywhere. It is pouring, thundering and raining here, and I could see the lightning striking down as I was driving to work. Which brings me to my questions:

How would a car get struck by lightning? Under what circumstances?
What would happen? Would the car stop dead in its tracks?
What do you do then? How do you get out of the car?
Would your car be damaged or destroyed?
Is there a difference between really new cars (this year), those made about 10 years ago, and 20, and so on?

Thanks - can't help but wonder.

How? In a thunderstorm.
Once the lightning hits, you can get out - it's over in an instant. Of course, being in a car is one of the safest places in a thunderstorm.
What would happen? It depends - there have been cases where the tires were popped, but most times very little damage occurs. You might need to get the car painted.
No, there is no difference. (although plastic cars, like the Corvette, offer less protection than metal cars.)

[CalMeacham]

Although the car is sitting on rubber tires, this doesn't necessarily serve as insulation sufficient to keep lightning from finding a path to ground through the skin of a car. Especially if it's raining, the water running down the car (especially considering what can get into the water -- they coat roads here in the Northeast with SALT all winter, and it takes a while to wash off) can form a conducting path for the lightning. Certainly if the car is the highest thing on a flat plane, it'll be an inviting target for a lightning strike.


Lightning strikes often go around the skin of the car, the lightning books tell me. A car is a rotten Faraday cage -- it's got those huge gaping holes where the windows are. Radio and phone signals easily go into a car. But the cage doesn't have to be perfect to protect you from lightning, or at least offer pretty good protection. The operator's cage at the Theater of Electricity at the Boston Museum of Science has pretty large openings in it, but it's reasonably effective.

I haven't heard or read of any cars being destroyed or having portions "spot welded" by lightning. I think you'd probably just opemn the door and step out.



People have raised the issue of fiberglass bodies. These wouldn't conduct, themselves, and so wouldn't give you the same protection as a sheet metal body. Although I suspect the bolt would rather pass along the exterior (especially if wet) than through the car.

[Really Not All That Bright]

Originally Posted by Anaamika

How would a car get struck by lightning? Under what circumstances?
What would happen? Would the car stop dead in its tracks?
What do you do then? How do you get out of the car?
Would your car be damaged or destroyed?
Is there a difference between really new cars (this year), those made about 10 years ago, and 20, and so on?

Not very scientific, but interesting and informative nonetheless:

obligatory Top Gear link

[wolfman]

A car is a rotten Faraday cage -- it's got those huge gaping holes where the windows are.

I've never heard that. Lightning usually jumps over a mile in a tiny crossection through air(a very poor conductor). If a can happens to be in the area between the areas of differential,Channeling all that flow through the much more conductive, fairly thick pillars seems an easy thing to to for the last 5 feet or so.

[TimeWinder]

I was driving a car once that I think was hit by lightning. The sound was an incredibly loud "hiss", not the crackle or bang I'd have expected. The light, though, was blinding, mostly in that it left afterimages of basically my whole field of view, like when you look into a flash bulb. Even though I was driving through a nasty thunderstorm, it was disorienting, sort of a "what just happened?" moment. My perception was of a "sheet" of light covering the windshield in an instant -- I certainly couldn't make out any bolts.

I don't know that it was my car that was hit, but it was very, very close. I didn't feel anything that I remember, and I didn't see any damage on my car later, or those cars around me at the time. The car didn't stop until I stopped it (I was in slow traffic because of the storm) to let my eyes adjust.

[Anaamika]

Wow. Another reason why this place is cool. You ask a question, and somebody actually comes out of the woodwork who has had it happen. Were you scared, TW? When you got out, did you notice anything? Paint scarring?

beowulff, when I asked how it would happen, I didn't mean strictly how - I meant why my car as opposed to all of the others, does it make a difference, it is random, etc. What if you were the only car in a field? What if you were the tallest car? Etc.

Thanks all for the answers!

[Really Not All That Bright]

Originally Posted by Anaamika

beowulff, when I asked how it would happen, I didn't mean strictly how - I meant why my car as opposed to all of the others, does it make a difference, it is random, etc. What if you were the only car in a field? What if you were the tallest car? Etc.

All of the above: height + conductivity + distance to next nearest conductive thingy = likelihood of being hit (assuming specific weather conditions are held constant).

Since holding weather conditions constant is obviously unlikely, a big part of it IS random, ie. what's close to the stepped leader forms?

[engineer_comp_geek]

Lightning is very unpredictable. If you are the tallest car you are probably more likely to be struck, but it's not guaranteed. Some people think that the tires insulate the car, but really that doesn't do anything. Air is a good insulator too, and lightning already jumped several miles through the air. A couple of inches of rubber are meaningless under the circumstances.

The body of a car does make a somewhat imperfect Faraday cage, as was already mentioned. I wouldn't call it "rotten" though. For the most part, the car body offers fairly decent protection. I have seen a couple of pictures of cars that were struck by lightning coming in through the front window. Fortunately, no one was inside of them at the time, but the damage was pretty severe. Most of the damage was to the dash and steering wheel. More often, the lightning hits the car body and you get fairly little damage, at least to the body of the car. Most often you see these little pinholes of damage near the roof and near the bottom of the car.

Older cars tend to fare better in lightning strikes because their electrical systems are much simpler and therefore more rugged. Newer cars can have their engine computers completely fried, which stops the car dead in its tracks. Again, though, lightning is unpredictable. Some cars get struck and their occupants aren't even sure that they got hit. Other cars die completely and have to get towed. It's mostly just dumb luck as to which scenario happens.

I've never read of car doors being spot welded or anything either. Usually the body damage is fairly minor. Even if the car dies on the spot you can just open the doors and get out once the car stops. I have heard of cars being totaled, but this is usually due to the electrical system being fried. It costs a lot to replace computers and wiring harnesses throughout the car.

Here's a youtube video of a minivan getting struck:
http://www.youtube.com/watch?v=lUUOdO6eEZA

This picture is pretty typical for the type of damage you see to a car:
http://www.wrh.noaa.gov/images/pqr/05082003_sle.jpg

[TimeWinder]

Originally Posted by Anaamika

Were you scared, TW? When you got out, did you notice anything? Paint scarring?

One of the advantages of lightning strikes is that they don't give you a chance to be scared . I didn't see any damage of any kind on the car, which is why wonder if I actually got hit, or if it was a vehicle next to/in front of me -- but I didn't see any damage on it, either. The car was an early-90's Saturn, so metal top but plastic sides.

[CookingWithGas]

Originally Posted by wolfman

I've never heard that. Lightning usually jumps over a mile in a tiny crossection through air(a very poor conductor). If a can happens to be in the area between the areas of differential,Channeling all that flow through the much more conductive, fairly thick pillars seems an easy thing to to for the last 5 feet or so.

I think when CalMeacham said that cars are rotten Faraday cages, this didn't mean that it would not conduct electricity, but that it wouldn't provide perfect protection for the contents of the car. Due to the large openings, some electricity could leak into the interior.

Great conductor, middling Faraday cage.

[spinky]

Originally Posted by engineer_comp_geek

Some people think that the tires insulate the car, but really that doesn't do anything. Air is a good insulator too, and lightning already jumped several miles through the air. A couple of inches of rubber are meaningless under the circumstances.

And even if the rubber were a good enough insulator, there's no reason to assume the path the lightning would take even goes through them. Remember; it's going to take the path of least resistance, which may very well be the 10 inches of atmosphere between the lowest piece of metal on your car and the ground. We know it can arc across miles of atmosphere; what's a few more inches?

[Really Not All That Bright]

Originally Posted by ntucker

And even if the rubber were a good enough insulator, there's no reason to assume the path the lightning would take even goes through them. Remember; it's going to take the path of least resistance, which may very well be the 10 inches of atmosphere between the lowest piece of metal on your car and the ground. We know it can arc across miles of atmosphere; what's a few more inches?

There may be a stream of water that reaches the ground itself if you're moving or it's raining hard.

[Q.E.D.]

Originally Posted by ntucker

Remember; it's going to take the path of least resistance...

No, it isn't. There is no "the path of least resistance." In conductors, electric current takes all possible paths, with the most current flowing through the paths of lowest resistance. That doesn't apply to lightning in air, which takes a largely arbitrary path determined by a number of factors including atmospheric conditions and the distribution of charge on the ground and objects on it. The final path that a ground lightning strike actually takes is fixed when the stepped leader (a channel of partially ionized air) from the clouds touches one of hundreds of streamers of charge that are pulled up from the ground and objects on it. One could make an argument for calling that a path of least resistance, but that path doesn't exist until the instant the strike is triggered.

[spinky]

Originally Posted by Q.E.D.

One could make an argument for calling that a path of least resistance

One could and does. It's a colloquialism and a useful way to visualize things. Sorry if it's not strictly true, but if you want to get down to that level of scrutiny, the whole concept of electricity "flowing" is invalid as well.

[Q.E.D.]

Originally Posted by ntucker

Sorry if it's not strictly true, but if you want to get down to that level of scrutiny, the whole concept of electricity "flowing" is invalid as well.

This ought to be good, but I'll bite. Let's hear it.

[racer72]

Originally Posted by Really Not All That Bright

There may be a stream of water that reaches the ground itself if you're moving or it's raining hard.

Something I remember from a trip to the Seattle Science Center when I was a kid. They had an exhibit on lightning and a kid asked about lightning and water. The science guy said it would take a large amount of water, at least a large pond, to transfer the power from a lightning strike. Any thing less, and this would include the rain running off the car, would be vaporized instantly by the heat of the lightning making it incapable of as a conductor of the lightning. A quick check on Google confirms this, the temperature of an average lightning strike is in the 50,000 to 60,000 degree range. This is what causes trees to blow apart when they are struck by lightning, the superheating of the pitch and water in the tree trunk.

I did see the aftermath of a vehicle that was struck by lightning, it was a ramp truck used to haul junk cars. The most damage was to the headache bar (the metal bars between the cab and back of the truck), it blew out a good chunk metal and the truck's electrical system was fried. The truck had a flat front tire and the wheel was in contact with the ground. While fixing the truck we found a few other odd things. There was very little brake fluid in the system, the wheel bearing grease where the tire was flat was gone and the chrome on the wheel began to flake off. The truck was only about 2 years olds so we knew brake fluid was full and there was plenty of bearing grease before the lightning strike.

[Q.E.D.]

Originally Posted by racer72

Something I remember from a trip to the Seattle Science Center when I was a kid. They had an exhibit on lightning and a kid asked about lightning and water. The science guy said it would take a large amount of water, at least a large pond, to transfer the power from a lightning strike. Any thing less, and this would include the rain running off the car, would be vaporized instantly by the heat of the lightning making it incapable of as a conductor of the lightning.

This is a little misleading as well. Definitely, the water would be instantly vaporized, however, it's presence in the first place could be enough to create a preferential path for the bolt to follow. Once the water is vaporized, it's absence no longer matters, since it's now the channel of ionized air that's conducting the lightning, anyway.

[elfkin477]

Originally Posted by TimeWinder

and I didn't see any damage on my car later, or those cars around me at the time. The car didn't stop until I stopped it (I was in slow traffic because of the storm) to let my eyes adjust.

This answers a question I had last weekend when I was woke from a sound sleep by lightning hitting something nearby - would a struck car sustain damage? I had the mental image of the console melting, but a suspicion that it'd be unlikely. Of course, I was thinking of a parked car!

[Spezza]

Been in a car struck by lightning. Went to a open parking lot on the edge of town as a nice thunderstorm was approaching. Security guard drove by and advised us to leave, we stayed. About 20 minutes later ZAP, huge noise and nothing but light. The next second, utter silence. A second later, back to normal rainfall and thundershowers. Other than that there was nothing besides the my girlfriend clutching my arm tightly, begging me to leave. We left.

No damage to the car. In hindsight, however, I cannot positively state the lightning hit us. Could have struck the pavement beside the car, or a lamppost nearby. In any case, it was damn close and damn cool.

[spinky]

Originally Posted by Q.E.D.

This ought to be good, but I'll bite. Let's hear it.

The concept of electricity as a fluid which flows through conductors is what we call an analogy. You think of electricity as a flow of stuff from an area of high electric potential to an area of lower electric potential, and resistance as a sort of constriction or blockage of the path the stuff is taking, but the actual stuff doing the moving isn't really moving that much. There's no "flow" of electrons moving from one end of the circuit to the other, there's simply a propagation of waves. And this has pretty much nothing to do with the discussion at hand, the gist of which is that the tires could provide ten million times the electrical resistance that the atmosphere does, and the bulk of the current would simply take the less resistant path. In other words, any insulating property the tires may have is pretty much completely irrelevant.

BTW, I think I heard someone say "centrifugal force" in another thread. We'll hold the fort here while you take care of that.

[Richard Pearse]

Originally Posted by elfkin477

This answers a question I had last weekend when I was woke from a sound sleep by lightning hitting something nearby - would a struck car sustain damage? I had the mental image of the console melting, but a suspicion that it'd be unlikely. Of course, I was thinking of a parked car!

I think it probably would. I've been in an aircraft that was struck by lightning, it had seven small holes around the fuselage and wings.

[LSLGuy]

A couple of years ago a coworker's car was almost struck while driving. It was a mid 90's Toyota Landcruiser. He saw the bolt impact a couple lanes away & a hundred-ish feet ahead.

The engine died immediately. Aftter he coasted to a stop the engine restarted, but ran like crap. The auto transmission would operate in 1st & 2nd but wouldn't go into 3rd or higher.

He limped into a nearby Toyota dealer. Later they told him the main computer was fried, but the vehicle was equipped with a non-computerized "limp home" mode that worked well enough to get him into the dealer. $1500 later he was back in business.

We both doubted the EMP from the bolt would be enough to do the damage, so we suspected there was a side strike that actually hit his vehicle. Never found any other damage.


Lighting - random, extremely powerful, and all-but-instant. You can see why the Ancients equated it with their god(s).

[Rick]

We did this once before, but it appears to be too old to search. in that thread, I mentioned of a case where a car was struck by lightning, and it destroyed every electronic control unit on board. Several small salvage rebuilders lost their ass trying to restore it to running condition.
Someone else posted a link to some pictures of a van that got hit while parked a fire resulted inside the van, or at least it looked that way.
So I feel safe is saying, your damage may vary.

[Muffin]

The Top Gear car review TV show put the hampster in a car and then zapped it with a gazillion megawhatits: http://www.youtube.com/watch?v=ve6XGKZxYxA

[Q.E.D.]

Originally Posted by ntucker

BTW, I think I heard someone say "centrifugal force" in another thread. We'll hold the fort here while you take care of that.

Centrifugal force is a completely real force inside a rotating frame of reference. It's only a fictitious force when examined from an inertial frame from reference. Ask any physicist.

BTW: Look up "flow" some time. At least one of its many definitions involves the flow of "stuff." Like photons.

I'll agree the concept of electricity flowing like water is flawed, but the term "flow" itself is not inherently incorrect. Electrical engineers use it, and not just in everyday speech, but also in professional papers. That's good enough for me.

[Crafter_Man]

Originally Posted by Q.E.D.

I'll agree the concept of electricity flowing like water is flawed, but the term "flow" itself is not inherently incorrect. Electrical engineers use it, and not just in everyday speech, but also in professional papers. That's good enough for me.

True, we use it. But we probably shouldn't.

A lot of EEs like to say "current flow" or "flow of current." I'm also guilty of it. It's a sloppy usage of terms for a couple of reasons. For one thing, current doesn't flow - charge flows. Secondly, we often use the "conventional direction" for the flow of charge, which is ass-backwards to what's really going on.

[Q.E.D.]

Originally Posted by Crafter_Man

For one thing, current doesn't flow - charge flows.

I disagree. Not that charge flows--surely it does--but that current doesn't. But, I think in order for any of this to make sense, we have to understand what our definitions of "flow" are. There are a number of definitions of the word here. I see a number of them which apply very well to current, don't you?

Bottom line is: current flows because we have defined it to be so.

[Crafter_Man]

Originally Posted by Q.E.D.

I disagree. Not that charge flows--surely it does--but that current doesn't. But, I think in order for any of this to make sense, we have to understand what our definitions of "flow" are. There are a number of definitions of the word here. I see a number of them which apply very well to current, don't you?

Bottom line is: current flows because we have defined it to be so.

When I look at a river, I would not say, "The current is flowing." Instead I would say one of the following:

"Water is flowing."
"There is a current."

At any rate, it doesn't matter. We all know what we're talking about.

[WarmNPrickly]

I saw a video of a couple of kids walking in a rainstorm when apparently lightning struck just a few feet from them. The weatherperson corrected this and said that what had actually struck was one of those streamers that go up from the ground to meet the step leader, but this one didn't actually meet the step leader so it wasn't a full on lightning strike. I wonder if a lot of people that think they get struck by lightning are actually hit by things like this, which in my mind explains why they survive. I find it very difficult to beleive that someone can get hit by a full on bolt of lighning and survive.

(Feel free to correct my vague understanding of the process.)

[mnemosyne]

I can't seem to find many picture of lightning damage to cars, but googling "aircraft lightning damage" yields several good pictures. There seems to commonly be round "bullet-hole" looking entry marks, and I assume either similar exit marks, or burn marks of some sort. I'd expect that a car getting hit directly by lightning would have similar damage.

Lightning strikes have caused accidents, though I haven't read all the reports to see what kind of instruments/controls were affected and whether they correlate to cars at all. I do notice that on an NTSB search using only "lightning" as a keyword, the fatalities are all Part 91 (general aviation) and not Part 121 (Commercial transportation). Would a car resemble a Boeing 737 or Airbus 319, or would it be more equivalent to a Cessna 495, a Beech 495? I also haven't read the reports to see if the lightning caused the fatality/injury, or if the ground did

[spinky]

Originally Posted by Q.E.D.

I'll agree the concept of electricity flowing like water is flawed

So what was that little "this ought to be good" throwdown about? Did you disagree then, but I convinced you, or do you just enjoy making people go on the defensive when it's not really called for? (rhetorical question; the answer is obvious)

[Q.E.D.]

Originally Posted by ntucker

So what was that little "this ought to be good" throwdown about? Did you disagree then, but I convinced you, or do you just enjoy making people go on the defensive when it's not really called for?

I'll ignore your claim that the answer is obvious, because apparently it isn't. You objected to the term "flowing," full stop. You never said anything about water. And neither did I until CM brought it up. If you don't see a difference between "flowing" and "flowing like water," well, that's your problem.

[spinky]

Originally Posted by Q.E.D.

You objected to the term "flowing," full stop.

Actually, I didn't, full stop. You and I both know (especially now that I have humored you and elaborated) that I wasn't referring to the term "flowing" by itself, but the commonly-understood-to-be-an-analogy-which-you-yourself-acknowledge-is-flawed concept of "electricity flow."

And the entire point is that I don't object to this. Mental models are useful, even when they're not 100% correct. It's going around picking pedantic fights that's not useful.

[Q.E.D.]

Actually what started this was my objection your claim that lightning follows "the path of least resistance." This is neither a useful nor correct model.

[spinky]

For purposes of deciding whether tires acting as insulators is going to make any difference, sure it's useful. I already explained this: the tires could be magical perfect insulators and it will basically make no difference, because the bulk of the current will just follow less resistant paths.