Am I going to die by lightning?
May 8, 2006 7:33 PM   Subscribe

How dangerous is it, really, to ride a steel-framed bicycle around in a thunderstorm?

Specifically, what are the chances that I am going to get hit by lightning and die - is riding a steel-framed bicycle around equivalent to carrying a lightning rod and shouting "pick me! pick me!"?
posted by irregardless to Travel & Transportation (14 answers total)
 
It depends on where you are biking. If you are in a featureless plain then yeah, you are in the most danger. But if you are in a city, the odds are much less that you will get struck. Any tall trees around you are more likely to get hit than you. All that said, it really isn't a good idea to bike or even walk in a heavy thunderstorm. But then life is all about taking chances.
posted by JJ86 at 7:44 PM on May 8, 2006


Electricity isn't attracted to metal, if that's what you think. And you misunderstand how a lightning rod works.

In a lightning strike there's an accumulation of one kind of charge in the clouds and an offsetting accumulation of the opposite charge in the ground. Eventually the voltage differential is enough to overcome the inherent resistance of the air and whatever else might be in between.

A lightning rod works by dissipating the charge that's underneath it in the ground. You've seen pictures of lightning striking a lightning rod, and that can happen, but usually the function of a lightning rod is not so much to be what lightning strikes as to be a way to keep lightning from striking at all, sort of by doing a constant slow "strike" all the time.

Metal has a lower resistance than air, and a lower resistance than the sheen of water on you when you get doused in a rain storm, and a lower resistance than your body does, but when it comes to lightning and the total resistance it's trying to overcome the difference in resistance is minor, and if lightning is likely to strike in the area you're in, it's almost as likely to strike you if you're just standing there as it is if you're sitting on a steel frame bike. The primary issue is how much charge has accumulated in the ground under you.

If there are trees or buildings near you (say, within 100 feet) then they're far more likely to be hit than you are no matter what you're riding or doing.

But if you're afraid, get off the bike and crouch.

That's safer than laying on the ground. The problem with laying down is that if there's a strike near you, current flows through the ground and your body laying on it offers less resistance than the soil does, so it'll take a short cut through your body. If you're crouching down, you minimize your height while having only one contact point with the ground.

(And presumably you know that standing under a tree is extremely stupid.)

All of this is theoretical; in practice very few people are hit every year in the US (a couple of dozen) and not all of those die. You have a better chance of winning the lottery, and that chance is vanishingly small.
posted by Steven C. Den Beste at 7:47 PM on May 8, 2006


This is, really, an impossible question to answer with any practical accuracy.
posted by rudyfink at 8:04 PM on May 8, 2006


obviously, if you know your Transformers classics, you'd recall that the rubber in your bicycle tires will insulate you from the detrimental effects of lightning.

well ... actually, no ... but I've ridden a steel bike through my fair share of thunderstorms and never noticed lightning bolts trying to play whack-a-mole with my top tube.
posted by bl1nk at 8:35 PM on May 8, 2006


... very few people are hit every year in the US (a couple of dozen) and not all of those die.

You are understating the occurrence of lightning strikes by at least a factor of ten, according to NOAA. More than 300 people each year suffer injuries from lightning strikes and undocumented injuries are higher. The number of deaths averages 67 per year. The greatest number of these occur in Florida, which has almost daily thunderstorms and lots of people engaged in outdoor activities.
posted by JackFlash at 8:50 PM on May 8, 2006


In one of my physics classes I remember being told if you are going to crouch down in a lightning storm remember to keep your feet together (same principle as what Steven C. Den Beste said applies).
posted by kechi at 9:08 PM on May 8, 2006


JackFlash, the fact remains that you have a much better chance of winning the lottery than you do of being struck by lightning.

In terms of hazards to life and health, lightning strikes are extremely low on the "things to worry about" scale. You're more than 500 times as likely to be killed each year in a car accident, for instance.
posted by Steven C. Den Beste at 10:08 PM on May 8, 2006


When you are leading paddling trips and there is lightning you are suppose to seek the lowest point on land and crouch (preferable on the balls of your feet) on your pfd. Lowest point to avoid lightning and the pfd (I assume) to avoid ground current.

Having said that, if I'm not leading a trip and it lightning I just stay put in the tent.
posted by edgeways at 10:27 PM on May 8, 2006


Steven has answered it well, but I can add a little anecdote.

I once cycled over the Metsovo Pass in central Greece during a springtime bicycle tour. The clouds had been gradually darkening all day and when we reached the top, an exposed, rocky and rather desolate place, the heavens opened and treated us to a spectacular thunderstorm. This was all rather impressive and entertaining until there were several lightening strikes in the space of about a minute, all around us. I've never before or since been anywhere so near to lightening - maybe 15-20ft away - and it was more than a little worrying. There was no obvious shelter available and the rain by then was belting down, so we decided the best thing to do would be to get on our (steel framed) bikes and head down the road from the pass as quick as possible. As we cycled off there were more lighting strikes to to rocks on the other side of the road.

Nobody got hit, despite some of the lightning striking points lower than we were. Either we were lucky, or rain soaked rocks are better conductors that fleshy mammals on steel-framed bicycles with rubber-shod wheels.
posted by normy at 1:59 AM on May 9, 2006


By the way, for what it's worth, I've read that if you really get caught out in a lightening storm with nowhere to go, you should crouch in a fetal position, knees on the ground, head off the ground but your backside highest of all. The theory goes that if you get hit the majority of the charge will travel through your bum thighs and knees, thus avoiding your heart and head and so far less likely to kill you. I've never heard of anyone actually testing this theory, however.
posted by normy at 2:12 AM on May 9, 2006


Regarding the rubber tires: nobody said they offered any protection by way of insulation, and in fact they don't. The amount of electricity in a lightning bolt simply jumps right through that amount of insulation (besides which the tires are wet). The reason you are pretty safe sitting in a car during a thunderstorm is not because of the rubber tires (a common misconception). It's because the lightning, if it hits the car, travels to the ground via the outside metal of the car. (As demonstrated daily in a very popular show at the Museum of Science in Boston).
posted by beagle at 5:05 AM on May 9, 2006


Yes, a metal car acts like a Faraday cage keeping the charge on the outside of the vehicle (and the show at the Museum of Science in Boston is highly recommended, but not for the feint of heart, literally).
posted by caddis at 7:32 AM on May 9, 2006


It seems like the best argument against riding your steel bike in these circumstances is that (A) you're much more likely to crash or get hit by a car, due to heavy rain, reduced visibility, high winds, wet pavement, etc. and (B) getting water inside of your steel frame will -- eventually, especially if there aren't proper drain holes in it -- ruin your bike.
posted by dseaton at 9:16 AM on May 9, 2006


I had lightning strike the earth some eight feet away from me whilst cycling in fairly open country on the north side of the South Downs (UK).Not an experience I am in a hurry to repeat.Point being that it did not choose to go to earth through my head but via a patch of nettles on the side of the lane.
posted by Dr.Pill at 12:40 PM on May 9, 2006


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