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Storms. Storms. A storm is a violent disturbance in the atmosphere. Storms involve sudden changes in air pressure , which in turn cause rapid air movements. . How Thunderstorms Form. Thunderstorms are heavy rainstorms accompanied by thunder and lightning. . Thunderstorms.
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Storms • A storm is a violent disturbance in the atmosphere. • Storms involve sudden changes in air pressure, which in turn cause rapid air movements.
How Thunderstorms Form • Thunderstorms are heavy rainstorms accompanied by thunder and lightning.
Thunderstorms • Thunderstorms form within large cumulonimbus clouds, or thunderheads. • Most cumulonimbus clouds and thunderstorms form when warm air is forced upward at a cold front.
Lightning • Lightning is a sudden spark, or energy discharge. • Lightning is caused by particles in a cloud rubbing against each other (friction) and creating electrical charges. • These charges jump between parts of a cloud, between nearby clouds, or between the cloud and the ground.
What causes thunder? • A lightning bolt can heat the air near it to as much as 30,000°C (54,032 F) • This is much hotter than the surface of the sun. • The rapidly heated air expands suddenly and “explodes.” • Thunder is the sound of the explosion. • Because light travels faster than sound, you see lightning before you hear thunder.
Tornadoes • A tornado is a rapidly whirling, funnel-shaped cloud that reaches down from a storm cloud to touch Earth's surface. • Tornadoes are usually brief, but can be deadly. • They may touch the ground for 15 minutes or less and be only a few hundred meters across, but wind speeds may approach 480 kilometers (300 mph) per hour.
How Tornadoes Form • Tornadoes develop in low, heavy cumulonimbus clouds—the same clouds that bring thunderstorms
Hurricanes • A hurricane is a tropical storm that has winds of 320 kilometers per hour (200 mph) or higher. • A typical hurricane is about 600 kilometers across. (300 miles)
How Hurricanes Form • A hurricane begins over warm water as a low-pressure area, or tropical disturbance. • If the tropical disturbance grows in size and strength, it becomes a tropical storm, which may then become a hurricane. • A hurricane gets its energy from the warm, humid air at the ocean's surface. • Hurricane winds may be as strong as 320 (200 mph) kilometers per hour.
The Eye of the Hurricane • The center of a hurricane is a ring of clouds surrounding a quiet “eye”. • The “eye” is an area of low pressure.
Hurricane Damage • When a hurricane comes ashore, it brings high waves and severe flooding as well as wind damage. • A storm surge is a “dome” of water that sweeps across the coast where the hurricane lands.