What is a thunderstorm?
A thunderstorm is a storm with lightning and thunder. Its produced by a cumulonimbus cloud, usually producing gusty winds, heavy rain and sometimes hail.
Cumulonimbus Cloud

What causes a thunderstorm?
The basic ingredients used to make a thunderstorm are moisture, unstable air and lift. You need moisture to form clouds and rain. You need unstable air that is relatively warm and can rise rapidly. Finally, you need lift. This can form from fronts, sea breezes or mountains.

When are thunderstorms most likely to occur?
Thunderstorms can occur year-round and at all hours. But they are most likely to happen in the spring and summer months and during the afternoon and evening hours.

How many thunderstorms are there every day?
It is estimated that there are around 1,800 thunderstorms that occur across our planet every day.

Are thunderstorms dangerous?
Yes, despite their small size, all thunderstorms are dangerous. Every thunderstorm produces lightning, which kills more people each year than tornadoes.

What is lightning?
Lightning is a bright flash of electricity produced by a thunderstorm. All thunderstorms produce lightning and are very dangerous. If you hear the sound of thunder, then you are in danger from lightning. Lightning kills and injures more people each year than hurricanes or tornadoes; between 75 to 100 people.

What causes lightning?
Lightning is an electric current. Within a thundercloud way up in the sky, many small bits of ice (frozen raindrops) bump into each other as they move around in the air. All of those collisions create an electric charge. After a while, the whole cloud fills up with electrical charges. The positive charges or protons form at the top of the cloud and the negative charges or electrons form at the bottom of the cloud. Since opposites attract, that causes a positive charge to build up on the ground beneath the cloud. The grounds electrical charge concentrates around anything that sticks up, such as mountains, people, or single trees. The charge coming up from these points eventually connects with a charge reaching down from the clouds and - zap - lightning strikes!
How Lightning Forms

Have you ever rubbed your feet across carpet and then touched a metal door handle? If so, then you know that you can get shocked! Lightning works in the same way.
Static Electricity

Click Here to see where lightning is currently striking across the U.S.

What causes thunder?
Thunder is caused by lightning. When a lightning bolt travels from the cloud to the ground it actually opens up a little hole in the air, called a channel. Once then light is gone the air collapses back in and creates a sound wave that we hear as thunder. The reason we see lightning before we hear thunder is because light travels faster than sound!

How do you know if lightning is nearby?
If you see dark clouds, then lightning could be present, but the best thing you can do is to listen for thunder. If you hear thunder, then you need to go indoors or get in a car. Don't be outside, where lightning could strike! If your hair stands on end or your skin starts to tingle, lightning maybe about to strike. Get down on your hands and knees and keep your head tucked in. Do not lay flat, because it can give lightning a better chance of strike you.

How far away can you see lightning and hear thunder?
Within those distant thunderstorms, the lightning bolts can be seen as much as 100 miles from us, depending on the height of the bolt, the clarity of the air, and our elevation. Thunder, in comparison, has a much shorter range of detection - usually less than 15 miles in a quiet rural setting and under 5 miles in a noisy city environment.

Can you tell how far away a storm is?
Yes, you can use thunder to tell how far away a storm is. Next time you see a storm, count the number of seconds between when you see the lightning and hear the thunder. Take the number of seconds and divide by 5 and that will tell you how far away the storm is in miles. For example: If you counted 10 seconds between the lightning and the thunder, the lightning is 2 miles away!
Counting How Far A Storms Is

What is hail?

Hail is created when small water droplets are caught in the updraft of a thunderstorm. These water droplets are lifted higher and higher into the sky until they freeze into ice. Once they become heavy, they will start to fall. If the smaller hailstones get caught in the updraft again, they will get more water on them and get lifted higher in the sky and get bigger. Once they get lifted again, they freeze and fall. This happens over and over again until the hailstone is too heavy and then falls to the ground.

What causes the wind to blow?
As the sun warms the Earth's surface, the atmosphere warms too. Some parts of the Earth receive direct rays from the sun all year and are always warm. Other places receive indirect rays, so the climate is colder. Warm air, which weighs less than cold air, rises. Then cool air moves in and replaces the rising warm air. This movement of air is what makes the wind blow.

What is a gust front?
A gust front is the leading edge of the downdraft from a thunderstorm. It is usually marked by gusty cool winds, and sometimes blowing dust. You will feel the wind from the gust front before it starts to rain.

Thunderstorm Know the Lingo Thunderstorm
SEVERE THUNDERSTORM WATCH - A severe thunderstorm (damaging winds of 58 miles per hour or more, or 1" hail in diameter or greater) is likely to develop in your area.

SEVERE THUNDERSTORM WARNING - A severe thunderstorm (damaging winds of 58 miles per hour or more, or hail three-fourths of an inch in diameter or greater) is taking place in your area.

DOWNDRAFT - A sudden descent of cool or cold air to the ground, usually with precipitation, and associated with a thunderstorm or shower.

UPDRAFT - A warm column of air that rises within a cloud. If the air is sufficiently moist, then the moisture condenses to become a cumulus cloud.

Thunderstorm Know the Facts Thunderstorm
DotThe typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes.

DotThunderstorms happen in every state and every thunderstorm has lightning.

Click Here to see if there are any active warnings in your area.

Thunderstorm Thunderstorm Safety Tips Thunderstorm
IF YOU’RE OUTDOORS: Keep an eye at the sky. Look for darkening skies, flashes of lightning, or increasing winds. Lightning often proceeds rain, so don’t wait for the rain to begin. If you hear the sound of thunder, go to a safe place immediately. The best place to go is a sturdy building or a car, but make sure the windows in the car are shut. Avoid sheds, picnic areas, baseball dugouts and bleachers. If there is no shelter around you, stay away from trees. Crouch down in the open area, keeping twice as far away from a tree as far as it is tall. Put your feet together and place your hands over your ears to minimize hearing damage from thunder. If you’re with a group of people stay about 15 feet from each other. Stay out of water, because it’s a great conductor of electricity. Swimming, wading, snorkeling and scuba diving are not safe. Also, don’t stand in puddles and avoid metal. Stay away from clotheslines, fences, and drop your backpacks because they often have metal on them. If you’re playing an outdoor activity, wait at least 30 minutes after the last observed lightning strike or thunder.

IF YOU’RE INDOORS: Avoid water. It’s a great conductor of electricity, so do not take a shower, wash your hands, wash dishes or do laundry. Do not use a corded telephone. Lightning may strike exterior phone lines. Do not use electric equipment like computers and appliances during a storm. Stay away from windows and doors and stay off porches.

IF SOMEONE IS STRUCK BY LIGHTNING: Call for help. Call 9-1-1 or send for help immediately. The injured person does not carry an electrical charge, so it is okay to touch them.

Thunderstorm Thunderstorm Activities Thunderstorm
Thunderstorm Experiment: Here is a great way to teach kids how to track a thunderstorm.

Thunderstorm Experiment: Here is a great experiment that shows kids how our weather works. It teaches them how thunderstorms are formed!

Lightning Experiment: Here is a great experiment that allows kids to make lightning in their mouth. It's a great way for them to understand how lightning works.

Lightning Experiment: Here is a great experiment that allows the kids to make lightning. All you need is a balloon and a light bulb!

Lightning Experiment: Here is another great experiment that allows the kids to make lightning. This teaches kids about the positive and negative charges and where they come from.

Static Electricity Experiment: Here is an experiment that allows the kids to learn about static electricity. This teaches kids about the positive and negative charges and where they come from.

Static Electricity Experiment: Here is another static electricity experiment. This teaches kids about the positive and negative charges and where they come from.

Static Electricity Experiment: Here is yet another static electricity experiment. This teaches kids about the positive and negative charges and where they come from.

Thunder Experiment: This experiment allows kids to make thunder, in a way that allows them to understand how it is made by lightning.

Pressure Experiment: Here is an experiment that shows how pressure is created in our atmosphere by sucking an egg in a bottle. This is a very cool experiment!

Make A Barometer Experiment: Here is an experiment that allows the kids to make a barometer.

Evaporation Experiment: Here is an experiment that shows kids how evaporation takes place.

Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.
Weather information