The Science Behind Mass Animal Deaths by Lightning: Why Hundreds Are Killed at Once

In a truly bizarre and unbelievable turn of events, a massive lightning strike recently claimed the lives of 323 reindeer in a remote, mountainous region of Norway. Finding over 300 animals lying dead after a single thunderstorm is a sight that wildlife officials called an unusually large natural disaster. The initial scene showed the reindeer clustered together on a plateau in southern Norway, having been caught in the lightning’s destructive path.

The big question everyone asks is: How does a single lightning strike kill over 300 animals simultaneously?

The answer lies in the science of electricity and how it moves through the ground.

The Real Danger Is the Ground Current

When most people picture a lightning strike, they imagine a bolt hitting a single point. While the visible flash does strike a precise point, the most lethal component is the subsequent ground current that radiates outward from the strike site.

According to lightning safety specialists, the current flashes through the ground and is extremely deadly to anything touching the earth within that radius. The electricity travels up one leg, surges through the body, stops the heart, and exits through another leg. The reindeer didn’t necessarily need to be touching each other; they only needed to be standing on the ground within the affected area to be electrocuted. Their natural tendency to group or huddle together during a severe thunderstorm only contributed to the massive scale of the tragedy.

Why Are Animals So Much More Vulnerable Than Humans?

It’s rare to hear about hundreds of people dying from a lightning strike, which raises another important question: What makes animals, especially large, four-legged ones, particularly vulnerable?

The explanation is simple, physics related to the points of contact with the ground:

• Four Legs vs. Two Legs: Humans are bipeds, meaning we typically have two feet close together.
• The Difference is the Gap: Animals like reindeer, cattle, and sheep are quadrupeds, and their four legs are often spread relatively far apart. This distance creates a larger potential difference, or voltage, between their legs.

When the ground current flows out from the strike, the voltage drop between an animal’s front and back legs is far greater than the voltage drop between a person’s two closely-spaced feet. This greater potential difference means a much stronger electrical current flows through the animal’s body and vital organs, increasing the chance of immediate death from cardiac arrest.

Not an Isolated Incident, But a Powerful Lesson

While this incident in Norway is freaky, it’s not the first time nature has demonstrated the sheer power of a lightning bolt. In fact, a larger tragedy was recorded in July 1918 when a massive 654 sheep were killed by a forked lightning strike in a mountain area of Utah.

These stories offer a profound and quite scary reminder of a lightning strike’s immense power. An average bolt of lightning packs an incredible punch, containing anywhere from 100 million to 1 billion volts of electricity and is capable of heating the air around it to temperatures five times hotter than the surface of the sun. It’s a humbling, sobering display of nature at its most destructive.