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Does lightning always strike the tallest object?

   Written by: LEE Lap-shun    September 2011


    Everyone knows that lightning is very dangerous.  However, there is a common misconception that lightning only strikes the tallest object.  Let us explore the facts behind this myth.

    Lightning stroke is initiated very high in thunderstorm clouds.  Objects on the ground have very little influence on its travelling path, until the stroke comes to a distance very close to the ground.  It is true that taller object is more susceptible to lightning because of shorter air gap between the lightning stroke and the object.  However, for any attraction effect to come into play, the lightning stroke has to be very close to the object.  The distance of influence is roughly equal to the height of the object.  For example, a 4-metre pole can only attract lightning strokes which are less than 4 metres away.  Therefore, do not assume that you are safe from lightning even if you see something else tall in your vicinity.

     

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    Fig.1  Although the pole is higher than the man, the man does not stand within the region of lightning attraction of the pole.  Therefore, there is still a chance for him to get struck.  (Objects in the diagram are not to scale)



Last revision date: <21 Dec 2012>