Hundreds of thunderstorms are happening all over Earth. First you see lightning, then you hear thunder. Thunderstorms help the planet by moving water, cleaning the air, and cooling down the temperature in some spots. In many forests the lightning from thunderstorms starts fires. While a fire is bad for people, in a forest, lightning fires help to clear out old brush and allow new trees to grow.
Many thunderstorms form when the sun heats up the ground and warm, humid air rises into the sky. That’s called convection. As clouds get larger, they hold more moisture. They even start to hold electric charge that instantly travels to create a flash of light, called lightning. When these large clouds produce lightning and rain, the cloud is a cumulonimbus- the thunderstorm cloud. Thunderstorms happen day and night, and they can happen when the air is cold as long as the air inside of them is rising fast. Some thunderstorms in winter create snow instead of rain!
Be careful around thunderstorms, because of lightning. Lightning is a huge spark of electricity that can shock you and it can even kill you. Lightning strikes in many different directions. Lightning that goes from the cloud to the ground is the most dangerous. Lightning hits tall things like trees, towers, and buildings, but it can hit anything. Not only is lightning electricity, but it is very hot. Lightning is so hot that it instantly heats the air, creating a shockwave, to make the sound of thunder. The noise of thunder travels much more slowly than lightning, so we always see lightning first, then we hear the thunder. When it takes a long time to hear the thunder it means the storm is far away. When the lightning and thunder happen at almost the same time the storm is close, and the thunder is louder. It's not the sound of thunder that can hurt you, it's the lightning
The convection that builds a thunderstorm makes air rise air in updrafts. A strong updraft builds a taller cumulonimbus cloud. Some clouds grow to over 10 miles tall. The top parts of these clouds get cold enough to hold tiny pieces of ice. A strong updraft allows pieces of ice grow bigger and bigger until they become so heavy that they fall. When ice falls from a thunderstorm, that is called hail. Hail tells us that the storm is very powerful. Hail can pile up to look like snow over a field or it can completely cover roadways.
Precipitation drags cool air out of the thunderstorm down to the ground, in a downdraft. The downdraft is the cool breeze you feel from a storm. If the downdraft is sudden and strong enough to knock over trees and cause damage, it's called a downburst or a microburst, and these are dangerous. A downburst or a microburst is a short burst of wind that can be stronger than a tornado. The wind speed can be more than 100 mph, and it could turn over mobile homes. The safest place to be, when a thunderstorm is this dangerous, is inside a strong building, away from windows.
Most thunderstorms do not get severe with extreme wind, but there may still be danger of floods. Stay away from floods, fast moving water, or water that you don't know how deep it is. Water is very powerful and heavy. It can move rocks and wash away soil in erosion in rivers, and beneath roadways. It can lift a car or truck and float it off the road. Water is strong enough to knock you over and carry you away.
On days when thunderstorms could become severe, there usually is a Severe Thunderstorm Watch and that means use your eyes, a weather app, and a weather radio to watch for fast changes. When a thunderstorm generates winds over 57mph, or hail larger than an inch, a Severe Thunderstorm Warning is issued, and you will hear an alarm on a weather radio to let you know danger is near.
Lightning, thunder, hail, and rain are all hazards of thunderstorms, but there is one other thing that only the strongest thunderstorms make. Tornadoes.