Thanks for picking up some of the links; I read through these. Wise Old Owl's link summed up lightning safety very well - it's one of the best write ups I have seen with statistics to back it up. Some of those conclusions were present in those linked discussions but not all.
Originally Posted by Wise Old Owl
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This is really the best answer for lightning:
Originally Posted by bacon_grease
The safest place to be in a lightning storm is FAR away.
My question is specifically about using the lightning position versus a hammock to protect from ground current. You have already done your best to get into a good location to minimize the chance of a direct strike or side flash. Now you have a choice to be in the lightning position or in the hammock. The name of the game here is to minimize the exposure to ground current and surface arcs - the parts of lightning that causes the most injuries and deaths. Not much can be done for a direct strike.
The main part of the lightning position is to minimize the difference in potential across your body. The ground current is traveling horizontally through the ground, so the potential changes with horizontal distance. Basically, you are a better conductor than the ground. If the difference in potential is great enough, the lightning will go up one leg to your body and down the other leg causing damage in the process. Hence, keep your feet together and keep the difference in potential as small as you can so that you don't get a large current passing through your body.
From page 6 of http://www.wec.ufl.edu/safety/Backco...ningSafety.pdf
"[T]he lightning position is for waiting out storms in stationary situations when it is impractical to move to a safer location.
1) Put your feet together
reduce the effects of ground current which causes about half of lightning fatalities.
reduce the effects of side flash and upward leaders which together cause ~40% of lightning fatalities.
3) Don't touch
long conductors to avoid contact voltage which causes ~20% of lightning fatalities."
One big thing to add to the question is that you are essentially a long conductor (2 meters) in a horizontal electrical field. I can see this causing arcing even if the there are no half decent conductors attached to you. Any electrical specialists care to run the calculations? Electrical fields are not my specialty so it would take me a while to work out the equations and correct assumptions. I'm not even sure of the voltages involved in ground current - I haven't been able to find them.
Now, assuming we haven't hung into a pickle, it comes back to the question about the suspension. If the suspension is a half decent conductor, the ground current could travel up one tree, through the suspension and through you - rendering the whole question about surface arcing moot. My guess is the same as BG, that it is not a good enough conductor and that it will either explode or melt . . . dumping you onto the ground.
Originally Posted by bacon_grease
What I'm looking into right now (in addition to that whole keeping the rig's DGPS's working thing) is finding out what will happen to a polyester rope when massive current is run through it. I suspect it will either explode from flash boiling water or burst into an explosion like flame that lasts less than a half second.
Does the ground current dissipate during the 0.2 seconds it will take for you to fall to the ground (hanging at 0.5 meter height)? Or is the voltage of the ground current low enough that it won't travel into trees? (Anecdotes seem to say it's high enough but I have no data.)