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What is Lightning?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

Lightning is a discharge of atmospheric electricity that is triggered by a buildup of differing charges within a cloud. The result is a sudden release of energy that causes a distinctive bright flare, followed by a thunderclap. Lightning is most common around the equatorial regions of the world, although it can potentially strike anywhere, and it appears in a variety of guises, depending on atmospheric conditions.

There are several competing theories to explain why differing electrical charges appear in clouds, although scientists suspect that it may be related to the presence of ice crystals. Typically, the bottom of a cloud becomes negatively charged, and it sends out what is known as a “leader” that seeks a positive charge, either in another cloud or on the earth. As the leader approaches an area that is positively charged, a positively charged streamer emerges, meeting the leader, sealing the connection, and generating a bolt of lightning.

Hail sometimes accompanies electrical storms.
Hail sometimes accompanies electrical storms.

After the lightning travels to the ground or another cloud, it may strike again several times within a fraction of a second. These re-strikes are so fast that people cannot register them with the naked eye; instead, they appear as a single strike. The electricity moves so quickly that it superheats the surrounding air, causing a sudden rapid expansion that creates a shockwave. Shockwaves are responsible for thunder; because thunder is so closely associated with lightning, some people attempt to judge the distance of a storm by counting the time which elapses between a strike and a thunderclap.

Positive lightning emanates from the ground and is extremely dangerous.
Positive lightning emanates from the ground and is extremely dangerous.

Most lightning travels from cloud to cloud, or from a cloud to the ground. In rare circumstances, however, the charges will be reversed, and lightening will emanate from the ground. This is known as “positive lightning,” and it is rare and extremely dangerous. It is often triggered by human activities, such as the liftoff of a rocket or the detonation of a nuclear device.

Those who cannot go inside during a lightning storm should hunch down close to the ground to avoid getting struck.
Those who cannot go inside during a lightning storm should hunch down close to the ground to avoid getting struck.

Many people associate classically jagged streaks in the sky with lightning, but it can also appear in bursts known as bead lightning, or it can reflect from the clouds, making sheet lightning. Some people may also be familiar with ball lightning, an unusual manifestation that is rarely observed.

An individual who is caught outside during a thunderstorm and who cannot take shelter in a car or house should hunch his body close together, making himself a small target, with only his feet touching the ground. People who are indoors should stay away from phones and plumbing, as lightning can sometimes travel through phone wires or plumbing systems.

Frequently Asked Questions

What causes lightning to occur?

Lightning is a result of the buildup and discharge of electrical energy in the atmosphere. This occurs when warm, moist air rises and collides with colder air, creating a charge separation. The buildup of electrical charges within a cloud, and between the cloud and the ground, eventually leads to a rapid discharge of electricity—lightning. The process is similar to static electricity but on a much larger scale.

How hot can a lightning bolt get?

A lightning bolt can reach temperatures of approximately 30,000 Kelvin (about 53,540 degrees Fahrenheit), which is hotter than the surface of the Sun. According to the National Severe Storms Laboratory, the extreme heat causes the surrounding air to rapidly expand and vibrate, which creates the thunder we hear following a lightning strike.

What is the difference between cloud-to-ground and intra-cloud lightning?

Cloud-to-ground lightning is a discharge between a thundercloud and the ground, visibly striking the Earth's surface. In contrast, intra-cloud lightning occurs within a single cloud or between multiple clouds. It is more common than cloud-to-ground lightning and is responsible for the majority of lightning discharges in a thunderstorm.

How far away can lightning strike from a storm?

Lightning can strike outward from a storm for up to 25 miles away from the thunderstorm cloud. These strikes are known as "bolts from the blue" because they seem to come from a clear sky. It's crucial to seek shelter if a thunderstorm is nearby, as lightning can reach you even when the storm seems distant.

Can lightning strikes be predicted?

While the exact location and time of a lightning strike cannot be predicted, meteorologists can forecast the likelihood of thunderstorms, which may produce lightning. Weather radar, satellite data, and atmospheric conditions are analyzed to predict storm development. However, the unpredictable nature of lightning strikes makes it essential to take precautions whenever thunderstorms are forecasted.

What safety measures should be taken during a lightning storm?

During a lightning storm, it is vital to seek shelter immediately, preferably inside a substantial building or a metal-topped vehicle with windows closed. Avoid open fields, high ground, trees, water, and metal objects such as fences or golf clubs. If indoors, stay away from windows, doors, and electrical appliances. The 30-30 rule is a good practice: go indoors if the time between seeing lightning and hearing thunder is 30 seconds or less, and stay indoors for 30 minutes after the last thunderclap.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

DylanB

@seag47 – It's Florida. I think this is because the weather there is so humid and warm for the majority of the year. Being surrounded by the ocean plays into this, too.

I vacation at the ocean nearly every summer, and I've noticed that thunderstorms roll in off the ocean just about every day. You can bank on having an afternoon thunderstorm even if you don't get one in the morning.

This is why I do most of my beachcombing right after sunrise. I wait until later in the afternoon to go shopping and eating at restaurants, because I don't feel safe on the beach when I can actually see the lightning in the distance.

Many people don't seem threatened by it. They just stay out there, determined to enjoy as much of their vacation as possible, regardless of the danger.

seag47

My local weatherman likes to put up a map of the state that shows the number of lightning strikes in each area during a thunderstorm. There seem to be a lot more of these strikes concentrated in one area during the summer storms than during the winter ones.

I live in Mississippi, and I am amazed at how much thunder and lightning we get during the summer. Does anyone know what the state with the most lightning strikes is? I will be shocked if it isn't my state!

Perdido

My dogs are very skilled at lightning detection. They start to act scared and hide in the closet before I can even hear thunder. Within a few minutes, it usually gets loud enough for me to hear it.

It's weird how some dogs are terrified of lightning and others couldn't care less about it. I've heard that it causes static electricity in their coats and this is what scares them, but if that's true, then how come all dogs aren't afraid?

Personally, I think it's the loud noise that terrifies them. If you heard something rumbling in the sky and you had no way of knowing what it was, wouldn't you be afraid?

OeKc05

Lightning struck the workshop in my backyard when I was young, and it shattered the concrete floor in one spot. After that, my dad decided to install some lightning protection.

He put a lightning rod on the roof. It was attached to something in the ground, so if lightning ever hit the building, it would travel down into the ground and not damage the shop.

anon290148

Does lightning come from the earth up or from the sky down?

anon165860

Some lightning comes from the ground up, but not all. There are four main types of lightning: cloud-to-ground, ground-to-cloud, intra-cloud, and inter-cloud.

anon47870

What is lightning in general? Is it sparks of electrons or plasma?

anon47770

actually lightening is caused by interaction of clouds elements on a large scale. this produces electric current in great excess and this heavy charge/current is at once transferred to the ground and lightning takes place.

anon38872

I was told that lightning is an optical illusion and comes from the ground up. Do you know if this is true?

elfi64

Lightning has a positive effect on the soil. Each time lightning strikes, it charges nitrogen into the soil, so in effect lightning can be viewed as a fertilizing agent.

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    • Hail sometimes accompanies electrical storms.
      By: Gavin Anderson
      Hail sometimes accompanies electrical storms.
    • Positive lightning emanates from the ground and is extremely dangerous.
      By: valdezrl
      Positive lightning emanates from the ground and is extremely dangerous.
    • Those who cannot go inside during a lightning storm should hunch down close to the ground to avoid getting struck.
      By: El Gaucho
      Those who cannot go inside during a lightning storm should hunch down close to the ground to avoid getting struck.