Lightning question

[D_B]

Sorry Guys, had to get my 5 posts. Here is the link to the study:


http://www.lightningsafety.com/nlsi_lhm/Radials.pdf

No joy with your link.

Works for me ... http://www.lightningsafety.com/nlsi_lhm/Radials.pdf

 

[jkaterenchuk]

A couple years ago I was diving in Madison Blue which is a cave system in NW Florida. We were doing a fairly long 1 1/2-2 hour dive. At one point during the dive my buddy was touching the side of the cave wall and got what he thought was a shock. When we finished our dive we surfaced to find a pouring rain storm. The park ranger and a few other divers were hiding in the bath house and told us that a lightning stike had hit a tree very close to the cave underwater path. I guess that is what my buddy felt with the shock underwater.

John

 

[Crush]

Sorry Guys, had to get my 5 posts. Here is the link to the study:


http://www.lightningsafety.com/nlsi_lhm/Radials.pdf

I have now been able to look at the article, briefly. The key (and incorrect) assertion with respect to safety in the water made in the article is that, based upon Figure 3, one can infer that the "discharge did not penetrate the body of water but, instead, created dendritic discharge patterns out over the water surface." The authors are confusing the absence of visible lightning (emission lines) within the water with the absence of electrical current. The radial lines of electrical discharge on the surface are spectacular, but you cannot infer that there is no current flow under the surface based upon the absence of discharge lines which will not ever be visible in lakes or oceans.

 

[victor]

I have now been able to look at the article, briefly. The key (and incorrect) assertion with respect to safety in the water made in the article is that, based upon Figure 3, one can infer that the "discharge did not penetrate the body of water but, instead, created dendritic discharge patterns out over the water surface." The authors are confusing the absence of visible lightning (emission lines) within the water with the absence of electrical current. The radial lines of electrical discharge on the surface are spectacular, but you cannot infer that there is no current flow under the surface based upon the absence of discharge lines which will not ever be visible in lakes or oceans.

You also cannot equate the land situation to the water case. The conductivity of the grass will be completely different to the conductivity of the earth below. This would not be the case with water where the conductivity 1mm below the surface should be the same as that at 1m.