In Hardangervidda, a mountain plateau in central southern Norway, a herd of 323 reindeer – 70 of them calves, were killed by a single lightning strike. You have probably heard about animals being struck by lightning and killed. But, is it even possible for animals on this scale to be killed by lightning at once?

In short, yes. Just a few months ago, 21 Cows in South Dakota were killed by a single lightning bolt, and in 1918, two large bolts of lightning struck and killed 654 sheep in Utah. Here’s what might have happened.

Usually when lightning strikes, the current flows into the ground, follows the path where there is less resistance and then finally goes outward. But in a cold place like the Hardangervidda, as the current runs into soil and it hits the permafrost layer, and spreads out along the surface of the soil. If it had been in somewhere warmer, the current would have had penetrated deep into the soil and dispersed off quickly. Also, the soil in Hardangervidda is saturated with rainstorms and water from annual cycles of melting. When a lightning strike, the energy goes along the ground surface and spreads quite far and wide.

As you know, voltage equals current multiplied by resistance. So when the current encounters the high resistance of permafrost, it magnifies the voltage experienced by any object, which in this case happens to be a herd of reindeer.

323 reindeer killed by lightning in Norway

Moreover in reindeer, the space between their front and back legs allows a large potential difference to developed, which is basically another voltage increase within the animal itself – as the current flows from front to back. So when the current runs along the ground, it encounters the front legs of reindeer. It then follows the path of least resistance, flows up the front legs, travels through the body – causing a jolt, which stops their heart and apparently kills in a spit second. The current then flows down to the back legs and finally, back into the ground.

Animals are more vulnerable to lightning because their legs are spread out more, the current travels more easily in their bodies affecting vital organs such as the heart and lungs. It doesn’t matter if they are directly struck by lightning or how close they are. If they are in the area hit by lightning, death is pretty much certain.

However in humans, the current bypasses the heart because of the distance between the legs; you might just get paralyzed temporarily.

Source(s): Wired, RedOrbit