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Thunderstorms

Cloud-to-ground lightning

I am petrified of thunderstorms. I have a dog and she is just as frantic as I am. She is able to predict when they are going to occur at least an hour before they are going to happen. I even lost her for over a week when a storm was approaching and she got loose. She ran down the West Bay Road and jumped into a surprised stranger’s car when he opened the door and refused to leave. I, too, hate being on my own when a storm approaches.

Did you know there are over 40,000 thunderstorms occurring throughout the world each day? They form when very warm, moist air rises into cold air. As this humid air rises, water vapor condenses, forming huge cumulonimbus clouds.

There are two main types of thunderstorms: ordinary and severe. Ordinary thunderstorms are the common summer storm and usually last about one hour. The precipitation associated with these storms includes rain and occasionally small hail. With ordinary thunderstorms, cumulonimbus clouds can grow up to 12 kilometers high.

Severe thunderstorms are very dangerous. They are capable of producing baseball-sized hail, strong winds, intense rain, flash floods, and tornadoes. Severe thunderstorms can last several hours and can grow 60 feet high. Several phenomena are associated with severe thunderstorms, including gust fronts.

Lightning is the most spectacular element of a thunderstorm. In fact it is how thunderstorms got their name because lightning causes thunder.

Lightning is a giant spark. A single stroke of lightning can heat the air around it to 30,000 degrees Celsius (54,000 degrees Fahrenheit)! This extreme heating causes the air to expand at an explosive rate. The expansion creates a shock wave that turns into a booming sound wave, better known as thunder. This explains why it has the name thunderstorm.

Thunder and lightning occur at roughly the same time, although you see the flash of lightning before you hear the thunder. This is because light travels much faster than sound.

Lightning is electricity.  It forms in the strong up-and-down air currents inside tall dark cumulonimbus clouds as water droplets, hail, and ice crystals collide with one another.  Scientists believe that these collisions build up charges of electricity in a cloud.  The positive and negative electrical charges in the cloud separate from one another, the negative charges dropping to the lower part of the cloud and the positive charges staying ins the middle and upper parts. Positive electrical charges also build upon the ground below.  When the difference in the charges becomes large enough, a flow of electricity moves from the cloud down to the ground or from one part of the cloud to another, or from one cloud to another cloud.  In typical lightning these are down-flowing negative charges, and when the positive charges on the ground leap upward to meet them, the jagged downward path of the negative charges suddenly lights up with a brilliant flash of light. Because of this, our eyes fool us into thinking that the lightning bolt shoots down from the cloud, when in fact the lightning travels up from the ground. In some cases, positive charges come to the ground from severe thunderstorms or from the anvil at the very top of a thunderstorm cloud.  The whole process takes less than a millionth of a second.

Kinds of Lightning
There are words to describe different kinds of lightning. Here are some of them:

In-cloud-lightning

In-Cloud Lightning: The most common type, it travels between positive and negative charge centers within the thunderstorm.


Cloud-to-Ground Lightning: This is lightning that reaches from a thunderstorm cloud to the ground.

Cloud-to-Cloud Lightning: A rare event, it is lightning that travels from one cloud to another.

Sheet Lightning: This is lightning within a cloud that lights up the cloud like a sheet of light.

Ribbon Lightning: This is when a cloud-to-ground flash is blown sideways by the wind, making it appear as two identical bolts side by side.


Bead Lightning: Also called “chain lightning,” this is when the lightning bolt appears to be broken into fragments because of varying brightness or because parts of the bolt are covered by clouds.


Ball Lightning: Rarely seen, this is lightning in the form of a grapefruit-sized ball, which lasts only a few seconds.

Bolt from the blue: A lightning bolt from a distant thunderstorm, seeming to come out of the clear blue sky, but really from the top or edge of a thunderstorm a few miles away.

When it comes to deadly weather, tornadoes and hurricanes get all the publicity, but lightning is actually the worst threat, killing more people on average every year than tornadoes and hurricanes combined.  About one hundred people die from lightning every year in the United States, and hundreds more suffer lifelong injury or disability.  In fact, the National Weather Service calculates a one-in-three hundred chance that you or a family member will be struck by lightning sometime during your lifetime.

No wonder my dog and I are very frightened of them.

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