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Steve Chesterton
(stevec1) - MLife

Locale: Midwest
Aluminum poles attract lightening?? on 04/07/2006 11:54:52 MDT Print View

Last summer while soloing in the Winds in Wyo, I pitched my BD Firstlight on a hill with an incredible view. I'm usually very careful about site selection, the momentary flat spot and the view was just too good. It occured to me that in the event of a storm it might be less safe in terms of lightning. Well, the storm did come, with a considerable pucker factor, but obviously I lived to tell. As you may know the Firstlight uses two aluminum poles. Carbon fiber is available, but you pay about ~$18 per ounce to save 6oz. So here's my question....Do aluminum tent poles increase your odds of a lightning strike as compared to carbon fiber poles? Thanks....Steve

Rick Dreher
(halfturbo) - MLife

Locale: Northernish California
Re: Aluminum poles attract lightening?? on 04/07/2006 12:14:17 MDT Print View

Hate to break it to you, but carbon's also a fine conductor so spending the extra dough won't improve your safety, just your pack weight :-(

Very generally, if I were in imminent danger of a lightning strike and was in a vulnerable spot, I'd ditch any obviously conducting gear and get to the safest place I could asap. If that meant leaving the tent and getting to a better spot, so be it.

(I carry a miniature set of lightning guidelines with me, copied from "Mountaineering, Freedom of the Hills", because I usually can't remember all the recommendations for finding the safest spot.)

Edited by halfturbo on 04/07/2006 12:14:44 MDT.

Mike Barney
(eaglemb) - F

Locale: AZ, the Great Southwest!
Re: Re:The highest Aluminum poles attract lightning?? on 04/07/2006 15:28:59 MDT Print View

I believe in the simplest form for calculating where lightning might strike, the tallest typically gets hit, typically regardless of the composition. (IF you're really interested, somewhere on the web is a 5th order differential equation you can use to predict where lightning will strike, enjoy. :)

The charge stored in a cloud seeks the line of least resistance to get to the ground. Most materials you're likely to find outdoor are better conductors than air. (You're competing against the resistance of air, and for practical purposes, as almost everything outdoors becomes a conductor at extreme voltages.) Even materials which may be insulators (like a PVC pipe sticking up on the top of a hill in a storm), but are wet, will still provide a lower path resistance than air. Also, just because you don't get hit with the main bolt, doesn't mean you are not a parallel path of slightly higher resistance, but you're still a path.

Further, at really high voltages and currents, electricity doesn't behave like it does in simple circuits, because the air, humidity, temperature, movement,charge, corona (not the beer) and a lot of other factors determine the actual path (that 5th order equation I don't care to revisit).

So the bottom line is, stay lower than other objects, and away from the tallest of objects. Lightning really does cause tree bark / limbs to explode off and kill or injure from the shrapnel.

2 years ago while camping, we were next to a group that set up a dining fly next to the tallest tree (yep, you guessed it). Lightning hit the tree, the kids standing next to the pole were zapped when the bolt jumped from the tree to the aluminum pole (they were also lower resistance paths to ground than air), and several others nearby were hit with flying bark. It was reeel clear where the bolt jumped to the pole. All survived, luckily. In this case, the lightning hit the highest object, ran down to a point 1 foot from the pole, and ran down the pole, while the corona reached out and zapped a couple of kids near by, and traveling on to the ground through the pole, tree and kids (and air).

I hope that makes sense.

MikeB

Edited by eaglemb on 04/07/2006 15:40:50 MDT.

Steve Chesterton
(stevec1) - MLife

Locale: Midwest
Aluminum poles attract lightening?? on 04/07/2006 18:40:53 MDT Print View

Rick, Mike

Thanks for the insight. Makes complete sense Mike. I guess it's down to just plain weight savings if I decide to go for carbon fiber, as Rick said, but not that I would buy carbon then pitch in hazardous places. Even in a well choosen site in the past, when I've been laying in the tent in the middle of the night with T&L going off around me, I've wondered if the aluminum poles were uping the odds, all the while that little voice in the back of your head is saying "This is Great!" (Not the thought of being zapped, just nature at her best!)

cary bertoncini
(cbert) - F

Locale: N. California
I think carbon much less conductive though on 04/07/2006 19:22:17 MDT Print View

right?

Lightning story: near Bishop Pass in Dusy Basin my father once found 2 guys dead in a tent w/ aluminum poles - tent had been hit w/ lightening.

Mike Barney
(eaglemb) - F

Locale: AZ, the Great Southwest!
"Safe" camping in a lightning storm? on 04/07/2006 20:14:22 MDT Print View

As to the campers that died in the tent @ Dusty Basin, If they were laying down, I would expect they were electrocuted once the
bolt hit the ground and spread out, (in literally the same way as a pebble makes concentric waves spread out when it's dropped into a pool) essentially shocking them from head to toe.

You could guard against this by building a Faraday cage, effectively a metal mesh / aluminum foil enclosure around the tent. Since charges of the same type (negative or positive) repel each other, the charge from a lightning bolt will only stay on the outside (since the like charges repels itself away from the inside). This is why you can take a direct hit of a lightning bolt in your car and be safe, assuming you're not hanging your hand out the window.

MikeB

Bernard Shaw
(be_here_now@earthlink.net) - F

Locale: Upstate New York
Insignificant differences on 04/07/2006 21:12:46 MDT Print View

Intuitively having a aluminum or carbon with you may only slightly change the path of a charge running along the ground, but it by itself is of such small significance that it is no consequence.

Lightning is caused by both sky and ground effects of large order of magnitude only.

The way this was explained to me in a WFR medical training is that we engage in magical thinking. That is, instead of getting into a more protected place we magically think if we get rid of the tent poles we are safer.

cary bertoncini
(cbert) - F

Locale: N. California
lightning above treeline on 04/07/2006 21:22:06 MDT Print View

my understanding in the sierras is that above treeline away from major peaks any major conductor (ie aluminum pole) is the most significant lightning rod around

2nd would be the human owner of the poles

so a broad open area, like Bishop Pass, Dusy Basin area, is major scary with electricity in the air because even without poles, you are the most attractive feature for lightning

Bernard Shaw
(be_here_now@earthlink.net) - F

Locale: Upstate New York
lightning is bigger scale than that on 04/08/2006 20:26:50 MDT Print View

That scrany piece of material is not significant to where lightning comes down and starts up. This is largely an egocentric idea, like the one that the sun revolves around the earth.

By far the biggest problem being up high is the increased frequency of strikes, wet soi conducting a strike nearby through the earth and the surface spread of the strike zapping you.

The best thing to do here is be on the driest soil, have a pad to crouch on with ankles together to keep the current ankle to ankle rather than up the body and down back to earth. Hands over ears to prevent ear drums blowing out. Praying probably helps to while away the minutes as well.