In a direct strike, the electrical currents in the flash channel pass directly through the victim. These severe injuries are not usually caused by thermal burns, since the current is too brief to greatly heat up tissues instead, nerves and muscles may be directly damaged by the high voltage producing holes in their cell membranes, a process called electroporation. Lightning strikes can produce severe injuries, and are lethal in between 10 and 30% of cases, with up to 80% of survivors sustaining long-term injuries. People caught in such extreme situations – without having been able to flee to a safer, fully enclosed space – are advised to assume the "lightning position", which involves "sitting or crouching with knees and feet close together to create only one point of contact with the ground" (with the feet off the ground if sitting if a standing position is needed, the feet must be touching). Warning signs of an impending strike nearby can include a crackling sound, sensations of static electricity in the hair or skin, the pungent smell of ozone, or the appearance of a blue haze around persons or objects ( St. Hallucinations may be induced in people located within 200 m (650 ft) of a severe lightning storm.EMPs – the discharge process produces an electromagnetic pulse ( EMP), which may damage an artificial pacemaker, or otherwise affect normal biological processes.This phenomenon (also responsible for reports of mass reindeer deaths due to lightning storms) leads to more injuries and deaths than the above three combined. The near-instantaneous rate of discharge causes a potential (difference) over distance, which may amount to several thousand volts per linear foot. Because the ground has high impedance, the current "chooses" a better conductor, often a person's legs, passing through the body. Ground current or "step potential" – Earth surface charges race towards the flash channel during discharge.
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