Lightning is a sudden electrostatic discharge that occurs typically during a thunderstorm. This discharge occurs between electrically charged regions of a cloud (called intra-cloud lightning or IC), between two clouds (CC lightning), or between a cloud and the ground (CG lightning).

 

The charged regions in the atmosphere temporarily equalize themselves through this discharge referred to as a flash. A lightning flash can also be a strike if it involves an object on the ground. Lightning creates light in the form of black body radiation from the very hot plasma created by the electron flow, and sound in the form of thunder. Lightning may be seen and not heard when it occurs at a distance too great for the sound to carry as far as the light from the strike or flash.

 

 

How does lightning form?

Lightning is an electric current. To make this electric current, first you need a cloud.

When the ground is hot, it heats the air above it. This warm air rises. As the air rises, water vapor cools and forms a cloud. When air continues to rise, the cloud gets bigger and bigger. In the tops of the clouds, temperature is below freezing and the water vapor turns into ice. Now, the cloud becomes a thundercloud. Lots of small bits of ice bump into each other as they move around. All these collisions cause a buildup of electrical charge.

 

Eventually, the whole cloud fills up with electrical charges. Lighter, positively charged particles form at the top of the cloud. Heavier, negatively charged particles sink to the bottom of the cloud. When the positive and negative charges grow large enough, a giant spark - lightning - occurs between the two charges within the cloud. This is like a static electricity sparks you see, but much bigger. Most lightning happens inside a cloud, but sometimes it happens between the cloud and the ground.

 

A buildup of positive charge builds up on the ground beneath the cloud, attracted to the negative charge in the bottom of the cloud. The ground's positive charge concentrates around anything that sticks up - trees, lightning conductors, even people! The positive charge from the ground connects with the negative charge from the clouds and a spark of lightning strikes.

 

 

Types of lightning:

-Cloud-to-Ground Lightning - Negative

-Cloud-to-Ground Lightning - Positive

-Ground-to-Cloud Lightning

-Intracloud Lightning

-Anvil Crawlers

-Bolt from the Blue

-Cloud-to-Air Lightning

-Bead Lightning

-Ribbon Lightning

-Sheet Lightning

-Sprites and Jets

 

 

Effect of lightning strike:

The effects of lightning are those of a high-strength impulse current that propagates initially in a gaseous environment (the atmosphere), and then in a solid, more or less conductive medium (the ground):

 

-visual effects (flash): caused by the Townsend avalanche mechanism

-acoustic effects: caused by the propagation of a shock wave (rise in pressure) originating in the discharge path; this effect is perceptible up to a range of around 10 km

-thermal effect: heat generated by the Joule effect in the ionized channel

-electrodynamic effects: these are the mechanical forces applied to the conductors placed in a magnetic field created by the high voltage circulation. They may result in deformations

-electrochemical effects: these relatively minor effects are consisting in the form of electrolytic decomposition in accordance with Faraday?s law –– induction effects: in a varying electromagnetic field, each conductor becomes the seat of an induced current

-effects on a living being (human or animal): the passage of a transient current of a certain r.m.s value is sufficient to incur risks of electrocution by heart attack or respiratory failure, together with the risk of burns.

 

 

Impact of a lightning strike:

Lightning is not only spectacular, it?s dangerous. 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. Strikes can cause cardiac arrest and severe burns, but 9 of every 10 people survive. The average American has about a 1 in 5,000 chances of being struck by lightning during a lifetime.

 

Lightning's extreme heat will vaporize the water inside a tree, creating steam that may blow the tree apart. Cars are havens from lightning—but not for the reason that most believe. Tires conduct current, as do metal frames that carry a charge harmlessly to the ground.

 

Many houses are grounded by rods and other protection that conduct a lightning bolt's electricity harmlessly to the ground. Homes may also be inadvertently grounded by plumbing, gutters, or other materials. Grounded buildings offer protection, but occupants who touch running water or use a landline phone may be shocked by conducted electricity.

 

 

Safety tips during lightning:

Safety precautions outdoors:

-If the weather forecast calls for thunderstorms, postpone your trip or activity.

-Remember: When thunder roars, go indoors. Find a safe, enclosed shelter.

-The main lightning safety guide is the 30-30 rule. After you see lightning, start counting to 30. If you hear thunder before you reach 30, go indoors. Suspend activities for at least 30 minutes after the last clap of thunder.

-If no shelter is available, crouch low, with as little of your body touching the ground as possible. Lightning causes electric currents along the top of the ground that can be deadly over 100 feet away.

-Stay away from concrete floors or walls. Lightning can travel through any metal wires or bars in concrete walls or flooring. Although you should move into a non-concrete structure if possible, being indoors does not automatically protect you from lightning. In fact, about one-third of lightning-strike injuries occur indoors.

 

Safety precautions indoors:

-Avoid water during a thunderstorm. Lightning can travel through plumbing.

-Avoid electronic equipment of all types. Lightning can travel through electrical systems and radio and television reception systems.

-Avoid corded phones. However, cordless or cellular phones are safe to use during a storm.

-Avoid concrete floors and walls.

 

Lightning strikes may be rare, but they still happen and the risk of serious injury or death is severe. So, take thunderstorms seriously.

 

 

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