Re: Lightning strike safe distance

To: tesla-at-pupman-dot-com
Subject: Re: Lightning strike safe distance
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
Date: Fri, 7 Jun 1996 08:54:08 +1200

Some things I've picked up about lightning strikes : I know that
it is possible to get killed some distance away. There have been 
recorded cases of cows killed near a strike. The mechanism is:
a wavefront propagates out from the strike point and this causes
a momentary potential difference to propagate radially away from the 
point of impact. With legs apart and (in the case of a cow which 
can't avoid it) some legs closer to the strike than others, a 
potential difference of some thousands of volts (depending on 
distance from the strike) may appear across those legs. Effectively,
the legs closest to the strike are suddenly elevated in potential
while the ones farthest away are left at zero for a short time.
     I guess my rules of thumb if you are threatened : better to 
crouch as close to the ground as possible with legs together than 
laying out flat on the ground.
     As always, I stand to be corrected.

Malcolm