Superficial lightning injuries--their "fractal" shape and origin.

The origin of superficial lightning burns was studied. A recently developed mathematical model was invoked to identify fern-shaped burns as 'so-called' fractals. On the basis of this model and discharge experiments, we conclude that 'fractal burns' are caused by surface discharges of a positive polarity. The recognition of such burns can help to elucidate the type and mechanism of the lightning strike.