LIGHTNING MARK ON THE GROUND

This image belongs to a lightning strike that occurred recently at a golf field. The imprint on the green has the same shape as the discharge from the cloud to the ground. Its length is around 6 meters. 

It is also appreciable that, as the current is impulsional, with a high frequency, it tends to flow on the soil surface.

Lightning protection standards (IEC/EN 62305, UNE 21186/1M) recommend a radial earthing with low impedance in order to dissipate correctly the electroatmospheric discharge.

For further information about lightning earthing systems click here.