Source: NASA

Throughout history man has been in awe of lightning. He has seen its devastating effects on the earth, people and plants. The discovery of fire may have been possible because of a lightning strike in our dim past. For most of our past lightning was a thing to be feared and worshiped, it was the fire from the gods. Well we have come a long way since then, but we realize today that our ancestors were right, lightning is a very dangerous phenomenon.

A typical lightning strike usually lasts under a second and is composed of three to four discharges.

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Over 40 million lightning strikes occur every year, which results in nearly 100 deaths. This number is an underestimate of the actual number of casualties because of the underreporting of suspected lightning deaths and injuries.

The action of rising and descending air within a thunderstorm separates positive and negative charges. Water and ice particles also affect the distribution of the electrical charge.

Lightning results from the buildup and discharge of electrical energy between positively and negatively charge areas.

An average flash could illuminate a 100 watt light bulb for more than three months.

The air near a lightning strike is heated to 50,000°F, which is hotter than the surface of the sun. The rapid heating and cooling of the air near the lightning channel causes a shock wave that results in thunder.

(Credit: National Weather Service)

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Source: NASA

Lightning discharges can be classified into two types:

Cloud to ground (CG) discharges. These discharges have at least one channel connecting the cloud to the ground [CG; or cloud to water (CW)].

Cloud discharges that have NO channel to ground. These cloud discharges are, in turn, classified as in-cloud (IC), cloud to air (CA), and cloud to cloud (CC).

(Credit: NOAA)

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Source: Sandia National Laboratory

In the past 30 years, approximately 85 Americans have been killed each year by lightning. Overwhelmingly, more males than females are killed by lightning, with most deaths falling in the age group from 10-39. Each year, many people are killed or injured by lightning when they stand under tall trees, walk across open fields, or are near, in, or on water (such as in boats).

Lightning is Utah's number one weather-related killer. 48 individuals have been killed by lightning in Utah since 1950.

The majority of lightning deaths occur during the months of July, August, and September (34). The county in Utah that has had the most lightning deaths is San Juan with 6.

On July 18, 1918, two large bolts of lightning struck and killed 654 head of sheep on Mill Canyon Peak in American Fork Canyon. According to one historical account: "Forked lightning had struck twice and split down two sides of the peak...There was about a seventy-five foot swath in between the dead sheep and where not a one was injured...The dead sheep all had to be moved to the opposite side of the canyon so as to be off the 'water shed.' Men counted them as they were moved, 654 sheep had been killed."

On September 1, 1939, lightning hit and killed 835 sheep that had been bedded down for the night on the top of Pine Canyon in the Raft River Mountains of Box Elder County in northwest Utah. Rain from a passing thunderstorm wet the ground and sheep, causing the lightning's electrical discharge to move completely through the herd of female sheep and lambs. The next morning, fifteen sheep (out of 850) were found alive but in a dazed condition. The sheepherder was knocked temporarily unconscious, but escaped death because he was in a tent. However, burned spots on his canvas tent revealed that he probably missed the fate of the sheep by only a slim margin.

The majority of wildfires in Utah are caused by lightning.

At any given moment, 2,000 thunderstorms are estimated to be underway around the world, and lightning strikes the ground about 100 times each second, or 8 million times a day. The U.S. has more thunderstorms than any other nation in the world, averaging over 100,000 thunderstorms a year; China is second in the world with over 85,000.

Lightning does strike the same place twice. The Empire State Building in New York City is struck about 23 times a year, on average.

When an aircraft in flight is struck by lightning, the aircraft itself usually induces the flash. Typically, there is little or no damage to the flying aircraft. Commercial aircraft are struck by lightning once every 5,000-10,000 flight hours.

(Source: NOAA)