Lightning Safety 101: Lightning Facts

Lightning strikes the ground approximately 25 million times each year in the United States alone. According to the National Weather Service, the chance of an individual in the U.S. being killed or injured during a given year is one in 240,000. Assuming an average lifespan of 80 years, a person's odds over their lifetime becomes one in 3000. Assuming the average person has ten family members and others with whom they are close, then the chances are one in 300 that a lightning strike will closely affect a person during their lifetime.

According to the National Weather Service, during the past 30 years (1979-2008) lightning killed an average of 58 people each year. Documented injuries average about 300 per year, although undocumented injuries are likely to be much higher.

About 2,000 people are killed worldwide by lightning each year. Hundreds more survive strikes but suffer from a variety of lasting symptoms, including memory loss, dizziness, weakness, numbness, and other life-altering ailments.

Taking the statistical percentage that only 10% of those struck by lightning are fatalities, this would mean that there are over 20,000 people struck by lightning each year around the world!

Lightning Fatalities Chart (NOLS)

 

Why have I not heard about many people getting struck by lightning?

As most strikes of persons are one or two at a time and spread across the world, it does not get the “press” that other natural disasters do.

 

Is it true that lightning can strike 10 miles away from a thunderstorm?

Yes, it is true. Lightning that strikes away from a thunderstorm are often called "bolts from the blue". Lightning has its own agenda. It is random and unpredictable, and defies our attempts to fit it into a convenient box to describe its behavior. Approximately 10% of all lightning related injuries and deaths occur due to these "bolts from the blue". We don't really know why it sometimes connects with the ground and not a tree, or a beach instead of the water.

A helmeted bicyclist experienced a lightning strike to the head under fair weather conditions with a cloudless sky. It was determined that the bolt probably originated in a thunderstorm that was about 16 km away and obscured by mountains.

 

What is a bolt from the blue?

A "Bolt from the Blue" is a cloud-to-ground flash which typically comes out of the back side of the thunderstorm cloud, travels a relatively large distance in clear air away from the storm cloud, and then angles down and strikes the ground. These lightning flashes have been documented to travel more than 25 miles away from the thunderstorm cloud. They can be especially dangerous because they appear to come from clear blue sky.

 

How long can a lightning bolt be?

Recent research from Vaisala-GAI's LDAR and LDAR II lightning detection networks show that lightning can travel 60 miles or more. The longest bolts start at the front of a squall line and travel horizontally back into clouds trailing behind the squall line. The longest bolt they have seen to date was 118 miles long in the Dallas-Ft. Worth, TX area. Since 3-D lightning measurements are relatively new, scientists are learning more every day and these numbers may change.

 

Can lightning be detected?

Yes, a lightning strike creates a unique RF signature that can be received and decoded by detectors such as the StrikeAlert Personal Lightning Detector and others. Since the 1980's, cloud-to-ground lightning flashes have been detected and mapped in real time across the entire US by several networks. In 1994, the networks were combined into one national network consisting of antennas that detect the angle from ground strike points to an antenna (direction-finder antenna), that detect the time it took for them to arrive at an antenna (time-of-arrival method), or a combination of both detection methods.

Flashes have also been detected from space during the past few years by an optical sensor. This experimental satellite covers the earth twice a day in tropical regions. The satellite also detects flashes that do not strike the ground, but cannot tell the difference between ground strikes and cloud flashes.

 

How can I stay safe from lightning?

When you're enjoying the great outdoors, be sure to carry a lightning detection device such as the StrikeAlert with you at all times. Know what to do if lightning strikes nearby or your detector alerts you of an approaching storm. NOAA's National Weather Service is also an excellent source for information on indoor and outdoor lightning safety and lightning risks.

 

What are the odds of being struck by lightning?

According to NOAA's National Weather Services, the odds of being struck in your lifetime (estimated to be 80 years) are 1 in 3,000. That's a greater chance than being attacked by a shark or being killed in a car accident.

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