Subject: Re: LIGHTNING and Tent Poles
From: Don Haines
Date: Tue, 24 May 94 13:35:27 GMT
Newsgroups: rec.backcountry

>I was wondering...(a dangerous thing)...whether aluminum tent poles are
>likely to attract more lightning than fibreglas?  They are a small thing
>compared to being camped on a hilltop or under the tallest tree around,
>but aluminum is a conductor so there must be some effect.
>
>[I was once in a large campground, in moderate to heavy forest cover, when
>lightning struck a particularly tall tree (hemlock?). It blew out about 5
>feet off the ground, jumping to the aluminum pole of a tent pitched close to
>the tree.]
>
>It is also a question right now since I am looking for a new tent.

Hi Gary, You are right about aluminum being a conductor and it does make a
difference. It seems quite reasonable that the lightning would jump across to
an aluminum pole. This is why you are safest near a tall object but not too
near.

It takes about 1000 volts to jump a gap of 1cm in dry air. Wet air makes a
better conductor. Water makes a fairly decent conductor. Dry wood does not.
As well we have the phenomena of electric charge accumulating on a point. The
lightning strike is attracted to the treetop because it is closer and is a
point. It travels down the wet sides of the tree and if it finds a better path
to ground (the tent pole) it will jump over and take it.

People also make good conductors. If you were that close to the tree you would
probably have gotten zapped. Some handy hints for sheltering from lightning
are:  1) Get out of the open. If you are the highest point then you are in big
         trouble.
      2) If you can't get out of the open, put your pack, walking stick,
         whatever, about 30 feet away from you, propped up high, and huddle on
         the ground.
      3) When sheltering in the trees, look for the highest tree and stay away
         from it. This is the local lightning rod. Be particularly worried if
         this tree is an evergreen because they conduct MUCH better then
         hardwoods.
      4) If you have time to rig a tarp or some rain shelter, do it! Water
         conducts and if you are dry your chances are better.
      5) If trapped on a lake find someone with a grumman canoe and mohawk
         paddles. Stay about 50 feet away because they are a lightning rod.

I was canoeing this weekend in La Mauricie park and we had a very powerfull
lightning storm. Several trees were blown over, winds hit at least 60kph
where I was sheltered in the woods, well over 100 in the open. A large pine
tree near camp took a direct hit and "exploded" into matchsticks. Kind of makes
you think about the raw power of a storm......

Don Haines