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Tornadoes are one of the most violent and powerful types of weather. They consist of a very fast rotating column of air that usually forms a funnel shape. They can be very dangerous as their high speed winds can break apart buildings, knock down trees, and even toss cars into the air.

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Kids learn about tornadoes including how they form, characteristics, types including supercell and waterspout, categories, and fun facts.

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Thunderstorms are a common weather disturbance. They are usually violent and short-lived. They almost always include thick clouds, heavy rain or hail, lightning, thunder, and...

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Science >> Earth Science for Kids

Weather - Hurricanes (Tropical Cyclones)

What is a hurricane?

A hurricane is a large rotating storm with high speed winds that forms over warm waters in tropical areas. Hurricanes have sustained winds of at least 74 miles per hour and an area of low air pressure in the center called the eye.

Different Names for Hurricanes

The scientific name for a hurricane is a tropical cyclone. Tropical cyclones go by different names in different places. In North America and the Caribbean they are called "hurricanes", in the Indian Ocean they are called "cyclones", and in Southeast Asia they are called "typhoons."

How do hurricanes form?

Hurricanes form over the warm ocean water of the tropics. When warm moist air over the water rises, it is replaced by cooler air. The cooler air will then warm and start to rise. This cycle causes huge storm clouds to form. These storm clouds will begin to rotate with the spin of the Earth forming an organized system. If there is enough warm water, the cycle will continue and the storm clouds and wind speeds will grow causing a hurricane to form.

Parts of a Hurricane

Eye - At the center of the hurricane is the eye. The eye is an area of very low air pressure. There are generally no clouds in the eye and the wind is calm. Don't let this fool you, however, the most dangerous part of the storm is at the edge of the eye called the eye wall.

Eye wall - Around the outside of the eye is a wall made up of very heavy clouds. This is the most dangerous part of the hurricane and where the highest speed winds are. The winds at the eye wall can reach speeds of 155 miles per hour.

Rainbands - Hurricanes have large spirally bands of rain called rainbands. These bands can drop huge amounts of rainfall causing flooding when the hurricane hits land.

Diameter - Hurricanes can become huge storms. The diameter of the hurricane is measured from one side to the other. Hurricanes can span a diameter of over 600 miles.

Height - The storm clouds that power hurricanes can become very tall. A powerful hurricane can reach nine miles into the atmosphere.

The structure of a hurricane

Where do tropical cyclones occur?

Tropical cyclones occur over the ocean in areas near the equator. This is because there is plenty of warm water in these areas to allow the storms to form. There are seven major areas in the world that tend to produce tropical cyclones. See the map below.

Locations of tropical cyclones throughout the world

When do hurricanes occur?

Hurricanes that form in the Caribbean and the Atlantic Ocean occur between June 1st and November 30th each year. This is called hurricane season.

Why are hurricanes dangerous?

When hurricanes strike land they can cause huge amounts of damage. Most of the damage is caused by flooding and storm surge. Storm surge is when the ocean level rises at the coastline due to the power of the storm. Hurricanes also cause damage with high speed winds that can blow downtrees and damage homes. Many hurricanes can develop several small tornados as well.

How are they named?

Hurricanes in the Atlantic are named based on a list of names maintained by the World Meteorological Organization. The names go in alphabetical order and the storms are named as they appear. So the first storm of the year will always have a name that starts with the letter "A." There are six lists of names and each year a new list is used.

Categories

Tropical cyclones are categorized according to the speed of sustained winds.

Tropical Depression - 38 mph or less

Tropical Storm - 39 to 73 mph

Hurricane

Category 1 - 74 to 95 mph

Category 2 - 96 to 110 mph

Category 3 - 111 to 129 mph

Category 4 - 130 to 156 mph

Category 5 - 157 or higher mph

Interesting Facts about Hurricanes

Hurricanes rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. This is due to the rotation of the Earth called the Coriolis effect.

The letters Q, U, X, Y, and Z are not used for the first letter when naming hurricanes.

The names are alternated between boy and girl names.

Weather forecasters draw a cone showing where they think the hurricane is most likely to travel.

You can always find out the latest information on hurricanes at the website of the National Hurricane Center which tracks and forecasts hurricanes.

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Earth Science Subjects

Science >> Earth Science for Kids

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Kids learn about hurricanes (Tropical Cyclones) including how they form, names, eye, eye wall, rainbands, locations, seasons, facts, and categories.

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Kids learn about tsunamis including what causes them such as earthquakes, where they occur, why they are dangerous, and what happens during a tsunami event.

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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.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.

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Most often flooding is caused by heavy rains over a long period of time. After a lot of rain, the ground becomes full of water, and new rainwater runs off, or flows downhill. That runoff goes directly into streams and rivers. In springtime the rain may be combined with melting snow. Because of the extra water flowing into the streams and rivers, their water level rises. If the level rises so much that the water overflows the banks, a flood occurs.

Flooding can be worse if there is not much vegetation (trees, grass, and other plants) on the land around rivers. In general, land that has little vegetation is less able to absorb water. The result is a larger amount of water entering a river system.

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When water overflows onto dry land, a flood takes place. Floods have always been a part of life on Earth. Almost every culture has a legend about a great flood. Since ancient...

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A volcano is an opening in Earth's crust. When a volcano erupts, hot gases and melted rock from deep within Earth find their way up to the surface. This material may flow...

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In an earthquake, huge masses of rock move beneath the Earth's surface and cause the ground to shake. Earthquakes occur constantly around the world. Often they are too small...

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Flooding Explanation- Learn about Flood- Video for kids

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What Is a Volcano? for Kids | Learn all about these unique landforms

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Earthquakes for Kids STEM | Learn why earthquakes happen and how to measure them

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What is thunderstorm? Why questions, science and home experiments for kids

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What's a Hurricane? | Weather Science | SciShow Kids

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What is a wildfire?
A wildfire also known as a wildland fire, forest fire, vegetation fire, grass fire, peat fire, bushfire (in Australia), or hill fire is an uncontrolled fire often occurring in wildland areas, but which can also consume houses or agricultural resources. Wildfires often begin unnoticed, but they spread quickly igniting brush, trees and homes.

What causes a wildfire?
Common causes of wildfires include lightning, human carelessness, arson, volcano eruption, and pyroclastic cloud from active volcano. Heat waves, droughts, and cyclical climate changes such as El Niño can also have a dramatic effect on the risk of wildfires. Although, more than four out of every five wildfires are caused by people.

Where can wildfires occur?
Wildfires can occur anywhere, but are common in the forested areas of the United States and Canada. They are also susceptible in many places around the world, including much of the vegetated areas of Australia as well as in the Western Cape of South Africa. The climates are sufficiently moist to allow the growth of trees, but feature extended dry, hot periods. Fires are particularly prevalent in the summer and fall, and during droughts when fallen branches, leaves, and other material can dry out and become highly flammable. Wildfires are also common in grasslands and scrublands.

What are the Santa Ana winds?
The Santa Ana winds are hot, dry winds that aggravate the fire danger in forests and bush lands. These winds characteristically appear in Southern California and Northern Baja California weather during autumn and early winter. In southern California, under the influence of Santa Ana winds, wildfires can move at tremendous speeds, up to 40 miles in a single day, consuming up to 1,000 acres per hour. Dense clouds of burning embers push ahead of the flames crossing firebreaks without a problem.

What is a fire tornado?
A fire tornado or fire whirl is just a tornado made of fire. It happens when certain conditions (depending on air temperature and currents), acquires a vertical vorticity and forms a whirl, or a tornado-like effect. Fire tornadoes may be whirlwinds separated from the flames, either within the burn area or outside it. A fire tornado can make fires more dangerous.

How do firefighters put out the wildfires?
Firefighters use a tool known as a pulaski. Its a combination of an ax and hoe used to dig a fireline. A fireline is a strip of land from which all brush and debris have been cleared to rob a wildfire of its fuel. Firefighters also use hotshots and smoke jumpers to clear a large path in a big circle around the fire so the blaze is contained in a ring of dirt. When the fire reaches this area, it runs out of fuel and starves to death. If the fire is too large, however, planes and helicopters fly overhead, dropping water and special chemicals that smother the flames. This pink, fire-retardant chemical is called sky jell-o.

Click Here to get the latest wildfire information.

Click Here for to get more wildfire information.

Click Here to see if there has been any recent wildfire activity across the U.S.

SURFACE FIRES - The most common type of wildfires, surface fires move slowly and burn along the forest floor, killing and damaging vegetation.

GROUND FIRES - These are usually started by lightning, ground fires burn on or below the forest floor through the root system.

CROWN FIRES - These fires spread by wind moving quickly along the tops of trees.

SANTA ANA WINDS - "Santa Ana" is the name given to the gusty northeast or east wind that occurs in Southern California during the fall and winter months. Santa Ana winds are often hot and very dry, greatly aggravating the fire danger in forests and bush lands.

CONFLAGRATION - A large and destructive fire, typically aggravated by strong winds that carry firebrands over natural or artificial barriers.

Click Here to learn about more wildfire facts!

BEFORE A WILDFIRE: Have a disaster plan. Know whether you're in a wildfire prone area. Plant fire resistant shrubs and trees around your home. Have a garden hose that is long enough to reach around your home. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water. Always listen to the radio and television for the latest information and instructions for your area.

DURING A WILDFIRE: If you're advised to evacuate then do so immediately. Wear protective clothing and lock your home. Tell someone you left and where you are going. Choose a safe route away from fire hazards. Watch for changes in the speed and direction of fire and smoke.

AFTER A WILDFIRE: Stay away from wildfire areas until it is safe.

Lesson Plan: Here is a great lesson plan on teaching students to have an escape plan if a fire threatens their home.

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.

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What is a wildfire? A wildfire also known as a wildland fire, forest fire, vegetation fire, grass fire, peat fire, bushfire (in Australia), or hill fire is an uncontrolled fire often occurring in wildland areas, but which can also consume houses or agricultural resources.

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The temperature outside is below freezing, the winds are howling, and you can barely see the tree in your front yard. A large amount of snow has been falling for more than three hours-a blizzard is under way.

According to the National Weather Service, blizzards are snowstorms with winds higher than 35 miles an hour and visibility (meaning, how far you can see) of less than a quarter mile. Winds from a blizzard can travel over 120 miles an hour-that's faster than a cheetah, the world's fastest land animal.

These conditions can be dangerous-low visibility can cause drivers to crash on roads, and high winds can topple power lines, which means some homes will be without heat. Large amounts of snowfall can trap people inside their homes. And those stuck outside in freezing temperatures can face frostbite or hypothermia, a condition in which your body temperature becomes dangerously low.

Learn more about these dangerous winter storms-and what to do if one comes your way.

How blizzards develop

Before you can have a blizzard, you first need snow. And for snow, you need clouds.

Clouds form when part of the air becomes cold enough that water vapor, which is the gas form of water, condenses and becomes tiny water droplets that form around things like dust and sea salt. When those droplets collect more water, they fall as rain. At temperatures between about minus 40°F and 32°F, the water droplets crystallize. When enough crystals stick together, they form snowflakes and fall to the ground.

What makes a snowstorm a blizzard is strong wind. First, warm air from the Equator mixes with cold air from the Arctic. Wind forms when warm air rises over the cold air; the faster the warm air rises over the cold air, the stronger the wind becomes.

Another type of winter storm is called a ground blizzard. This is when gusty winds-often 50 to 60 miles an hour-lift up snow that's already on the ground. Both types of blizzards can cause whiteouts, a condition in which so much snow is blowing so fast that it's hard to see anything. Sometimes you can't even tell the difference between the sky and the ground!

Blizzards in the future

Blizzards occur all over the world. But because they're closer to the Arctic, places like Russia, central and northeastern Asia, northern Europe, Canada, and the northern United States experience more blizzards than other parts of the globe.

And though most blizzards occur during winter, they can happen during other seasons, too. One of the most severe blizzards in the United States-known as the Great Blizzard of '88-happened in March 1888, killing more than 400 people.

Scientists believe that as global temperatures continue to rise because of climate change, blizzards could become more extreme. A warmer atmosphere means more moisture in the air that will eventually fall as snow (or rain); many also believe that warmer temperatures will create higher winds.

How to survive a blizzard

The best way to survive a blizzard is to prepare for extreme weather. Meteorologists use certain words and phrases that will help you know when a blizzard is coming. For instance:

Wind chill factor: This is what the temperature feels like outside, even if the real temperature is higher. Blizzards usually have wind chill factors of 10°F or lower.
Winter storm outlook or watch: This means that conditions are right for a snowstorm or blizzard to form.
Winter weather advisory: This means that dangerous winter weather is happening, which could be a blizzard.

Learn more about ways you can protect your family from dangerous winter weather.
Before a blizzard:
* Ask your parents to "winterize" your house: Check that heating sources are clean and working, and make sure windows are insulated so cold air can't come in. (If they're not, apply plastic sheets on the inside.)
* If you have a fireplace, stock up on firewood or coal.
* Make sure your family has a home emergency kit: water (at least a gallon for each person per day for several days), food (non-perishable or canned items for several days), flashlight, extra batteries, first-aid kit, manual can opener, local maps, battery-powered radio, and cell phone with a backup battery.
* Charge devices like cell phones.
During a blizzard:
* Listen to local radio or news for updated weather information.
* Layer up if you lose power. Try a t-shirt under a long-sleeved shirt under a sweater under a coat. That way you can take off items if you start to sweat. (Being cold and wet will just make you colder!) Other must-haves: two pairs of socks, mittens instead of gloves, a thick scarf, and a hat.
* Drink lots of water-or hot cocoa, or tea, or whatever-to stay hydrated. You might not think you need as much liquid in the winter as you do in summer, but staying hydrated helps your body generate enough heat to maintain a healthy body temperature.
* Evacuate only if you lose power and your home becomes too cold to stay in. Try to find a shelter-like a nearby school or library-that has heat and electricity.
If you must leave your house:
* Try to travel during the day when visibility will be better.
* Load up on blankets, canned fruits, bottles of water, and warm fluids in a thermos; bring an external battery in case you need to recharge your cell phone.
* Don't forget the layers!
* If you get stuck in your car, huddle with your companions for extra warmth.
* If you're caught outside, huddle together against a tree or a rock ledge to block the wind, and do not sit down on snow. (Your non-frozen butt will thank you.) And don't eat the snow-that could dangerously lower your body temperature.
* If you or your companions show signs of hypothermia or frostbite (shivering, feeling very tired, confusion, drowsiness, memory loss, slurred speech), seek help immediately.

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Learn how these winter snowstorms form-and how you can stay safe if one blows your way.

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What is a Blizzard? | Winter Science | Weather Science | SciShow Kids

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What is a Hailstorm? + more videos | #aumsum #kids #science #education #children

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Toss supercooled water into an updraft of air within a thundercloud and what do you get? A hailstorm!

Subjects

Earth Science, Meteorology

Image

Hail Damage to Minivan Windshield

Hail is supercooled water, which is refrozen in the atmosphere, before falling back to the ground as a sizable ice ball. Hail can cause severe damage to life and property, like this minivan windshield.

Photography by mwesselsphotography

Imagine balls of ice, some small, some the size of grapefruits, crashing to the ground in a storm. Sound like a nightmare? For people who experience these storms, it can be. Those balls of ice are hailstones, and they can damage cars, airplanes, and crops, and in some circumstances can even kill animals and people.

Hail forms from supercooled water. Supercooled water is something unique-it's water that is below its normal freezing point of 0°C (32°F) and yet remains a liquid. Scientists aren't exactly sure how this happens, but they do know that it occurs frequently in the upper atmosphere. Supercooled water will freeze when it comes in contact with something, like an ice crystal, dust particle, or raindrop. Hail is associated with high, vertical cumulonimbus clouds, the kind of clouds that produce severe thunderstorms.

Within a cumulonimbus cloud, ice particles develop from supercooled water. The particles fall toward the bottom of the cloud from the pull of gravity, but they are forced back up by powerful updrafts of air within the clouds. In the upper part of the cloud, they encounter more supercooled water, which freezes on the ice particles, adding another layer of ice to them. This happens repeatedly. In this way, the small bits of ice grow larger and larger, becoming balls of ice-hailstones. The hailstones finally become too heavy to be lofted back up to the top of the cloud and they fall to the earth.

Because of the way they form, hailstones have a layered structure, like an onion. Really large hailstones form in storm clouds with exceptionally strong updrafts.

The National Weather Service in the United States defines large hail as being at least 2.5 centimeters (one inch) in diameter. That's about the width of a quarter. This size distinction is important because hailstones this size or larger can cause damage to property, crops, and structures. It is difficult to determine the speed hailstones fall from clouds. But one estimate, from the National Severe Storms Laboratory, is that a hailstone the size of a baseball will fall at about 161 kilometers (100 miles) per hour.

Hail does significant damage to homes and crops worldwide. One of the most devastating hailstorms in U.S. history hit near Phoenix, Arizona, in October 2010. Hailstones as big as 7.6 centimeters (three inches) were reported and $2.8 billion in damage was done. The largest hailstone ever recovered in the United States was produced by a storm in the U.S. state of South Dakota in June 2010. It was 20 centimeters (8 inches) in diameter and weighed about 0.9 kilograms (two pounds).

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Director

Tyson Brown, National Geographic Society

Author

National Geographic Society

Production Managers

Gina Borgia, National Geographic Society

Jeanna Sullivan, National Geographic Society

Program Specialists

Sarah Appleton, National Geographic Society, National Geographic Society

Margot Willis, National Geographic Society

other

Last Updated

October 19, 2023

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Toss supercooled water into an updraft of air within a thundercloud and what do you get? A hailstorm!

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During a blizzard the wind blows at speeds of more than 35 miles (56 kilometers) per hour for at least three hours. Visibility (the distance you can see) drops to 0.25 mile (0.4 kilometer) or less. When the weather conditions are this bad, main roads and railways may have to be closed, and power and telecommunications lines may stop working.

In a severe blizzard, the wind speed increases to more than 45 miles (72 kilometers) per hour. Visibility drops to near-zero, and temperatures fall to 10 °F (−12 °C) or lower. All local roads and transportation systems may have to close. When a severe blizzard becomes so bad that it is impossible to see where the ground ends and the air begins, it is called a "whiteout."

A ground blizzard occurs when snow has stopped falling and high winds are blowing around the fallen snow. Ground blizzards are most common in wide, open fields or flat spaces.

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A blizzard is a powerful snowstorm. Low temperatures, strong winds, and large amounts of snow together create this dangerous weather condition. During a blizzard, the driving...

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You feel the ground suddenly shake, and nearby objects are trembling. An earthquake is happening.

Also called a temblor, an earthquake is caused by the movement of parts of the Earth's crust, its outermost layer. They happen millions of times a year, but most are so small people don't even feel them.

But powerful earthquakes can cause landslides, tsunamis, flooding, and other dangerous events. Most damage and deaths happen in places where a lot of people live, because the shaking causes windows to break, structures to collapse, fire to break out, and other dangers.

Learn more about these unpredictable Earth tremors-and what to do if one rattles near you.

How earthquakes develop

The action all starts thousands of miles below your feet.

Picture Earth as a hard-boiled egg: Earth's core is the yolk, and the mantle is the white part. The outer crust is the eggshell.

People live on the surface of the crust. Below the surface-but still within the crust-are tectonic plates. Like gigantic puzzle pieces, these huge slabs of rock encircle the Earth. The seven major plates are named for the regions they rest under: the African, Antarctic, Eurasian, Indo-Australian, North American, Pacific, and South American tectonic plates

Tectonic plates aren't connected but are close together. Where they meet along their edges is called a fault. When heat from the Earth's core creates currents in the crust, the tectonic plates can scrape, bump, or drag along each other. This is what causes an earthquake-and why the surface sometimes cracks like an eggshell.

How to measure earthquakes

About a half-million quakes rock the Earth every day. Usually the quake is too small, too far below the surface, or too deep in the seafloor to be felt. Some, however, are so powerful they can be felt thousands of miles away.

The spot on the surface just above where an earthquake starts is called the epicenter. Ripples called seismic waves travel out from the epicenter. This causes vibrations that people can feel, sometimes very far from the epicenter.

How far away people can feel an earthquake's vibrations depends on its size, or magnitude. Scientists base the magnitude on the strength and duration of the quake's seismic waves. The higher the number, the more powerful the earthquake: A magnitude 3 to 4.9 earthquake is considered minor; 5 to 6.9 is moderate to strong; 7 to 7.9 is major; and 8 or more is an extremely powerful temblor.

As the crust settles after an earthquake, another temblor called an aftershock can happen. Usually, aftershocks are not as powerful as the first quake but can still be very strong.

Geologists can't predict earthquakes. But they're working to change that with new research and technology.

Where earthquakes happen

Earthquakes occur along faults, the areas where tectonic plates meet. About 80 percent of earthquakes occur along the rim of the Pacific Ocean. Called the Ring of Fire because of the large number of volcanoes there, the area is a meeting point for many tectonic plates.

Earthquakes are also common in California because the region sits on top of the Pacific and North American tectonic plates. Temblors happen when these two plates grind against each other. About two-thirds of this movement happens along the San Andreas Fault.

Another major earthquake area in the United States is the New Madrid Seismic Zone, which affects Missouri, Arkansas, Tennessee, Kentucky, and Illinois.

How to survive an earthquake

Earthquakes can happen anytime or anywhere-even if you don't live near a fault. So it's a good idea to prepare.

* Talk with your family about the safest places in your home in case an earthquake hits. This could be under a sturdy table or next to an interior wall (one that is not connected to the outside).

* Look for heavy items that could fall or break during a quake, and move them to safer spots.

* Ask your parents to make sure you have an emergency kit containing things like first-aid supplies, a flashlight, a cell phone charger, and a battery-operated radio. Your family should also have enough food and water for at least 72 hours

DURING AN EARTHQUAKE: Most earthquakes last only 10 to 30 seconds, so it's important to get to a safe place fast. Remember three things during an earthquake: drop, cover, and hold on.

Drop: Get down on your hands and knees and crawl to your shelter.

Cover: Underneath a sturdy table, desk, or bed, cover your head and neck with your arms. If furniture isn't nearby, crouch down on your knees with your arms over your head and neck next to an interior wall. (Don't stand under a doorway-they can easily collapse.)

Hold on: If you're under a piece of furniture, hold on with one hand and move with the furniture if it starts sliding. Stay where you are until the shaking stops.

AFTER AN EARTHQUAKE: Once the earthquake ends, check for injuries. Listen to a radio for any warnings and instructions from official organizations like the United States Geological Survey. Be prepared for any aftershocks.

Text and images adapted from Everything Volcanoes and Earthquakes: Earthshaking photos, facts, and fun!

(Learn more about earthquakes at National Geographic.)

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Learn the science behind how earthquakes happen-and how you can stay safe if one hits.

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Volcano facts | National Geographic Kids

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Check out these fascinating volcano facts with National Geographic Kids! What is a volcano? Why does it erupt? And where can you find the world's biggest?

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Rain is pouring hard and fast-more than eight inches in just an hour, turning river water brown with mud. Earthworms wiggle up to the ground as the soil becomes too wet for them. A flood might be coming.

Just about any place on Earth can experience flooding. When so much rain falls that the ground can't absorb it or waterways can't hold it, the overflowing water becomes a destructive force. In the United States, flooding causes more death and damage than tornadoes, hurricanes, or lightning.

How floods develop

During a rainstorm, precipitation-or the water that comes from rain or snow-goes to different places. Some of it flows into streams, lakes, or city water systems. Other precipitation evaporates and returns to the atmosphere.

But much of the rainwater is absorbed by soil. It flows through the top layer of the ground, to plant roots below the surface. This helps provides plants with the water and nutrients they need to grow. The excess water moves deeper into the ground through layers of dirt and rocks where until it becomes part of natural underground wells called groundwater.

A habitat can naturally absorb a healthy amount of rainfall it needs to thrive. But too much rain can cause lake and river levels to rise and overflow their banks, or the soil to become too wet to absorb more water. And though you might think extremely dry habitats would welcome too much rain, it turns out that the parched dirt can't absorb the rain fast enough to capture it all.

Severe coastal storms, quickly melting ice and snow, and collapsed barriers (like concrete dams) can also cause floods. Even damaged beaver dams can lead to an overflow of water that the surrounding earth can't absorb.

Different types of floods

Floods can form slowly over several days or overwhelm an area with little warning. How quickly a flood forms often depends on the habitat.

Slow-forming river flooding happens in regions called floodplains. These are large, flat areas of land along waterways with very shallow banks. When big storms hit, the water overflows the banks and spreads out across the plains.

This type of flooding isn't always bad. It brings nutrients to the surrounding soil, making it fertile for growing crops. That's why many people live in or near floodplains.

But too much water can destroy crops and damage homes. Rushing water can disrupt ecosystems by moving aquatic plants and animals to other habitats. And if flooding is so severe that it flows into local water treatment facilities, experts must monitor the incoming water to make sure the water is safe.

Another type of flooding is called a flash flood, when a flood happens within six hours of a heavy rainfall-as much as eight inches an hour. With no place to go, the moving water will tear through highways, valleys, and canyons, washing away vehicles, roads, bridges, and houses.

Quickly melting ice and snow can also cause flash flooding, especially when mountain snowmelt overflows the waterways below. On coastlines, hurricane rains cause water levels to rise, and the high winds push that water onto land. Called a storm surge, this also causes flash flooding.

Flooding in the future

Scientists believe that warming temperatures caused by climate change are increasing the risk of floods all over the world, especially in coastal and low-lying areas.

Warmer water changes the patterns of ocean currents, which changes global weather patterns. This means that some places will receive more rainfall than the ground can absorb. Other places will get less rain so the land will be drier-and unable to handle rainfall when it does occur.

Scientists think that climate change could also cause stronger hurricanes, with more rain and higher winds causing bigger storm surges. A warmer climate could also mean more snowmelt overwhelming the soil; melting polar ice could cause sea levels to rise and increase flooding. ( Find out how you can help slow climate change.)

How to survive a flood

Experts might issue a flash flood watch if weather conditions are right. It doesn't mean flooding will happen but that meteorologists want people to be prepared. When experts are sure a flash flood is on the way, they issue a warning so people can evacuate immediately. Here's how to keep you and your family safe.

Before a flood
* Know your neighborhood. Research how close you are to streams, drainage channels, canyons, and any other low-lying areas that might flood.
* Keep emergency contact phone numbers in one place so you can get in touch with family members.
* Put together an evacuation plan and share it with everyone in your household. Know what paths and routes you can use to quickly get to a high, dry place.
* Conduct flood drills to practice evacuating quickly.
* Maintain an emergency kit with a three-day supply of food and water. Experts recommend canned or dried foods that don't need to be cooked, and at least one gallon of water per day for each person and pet.

During a flood
* Never wait for orders to leave; if you think a flood might be coming, evacuate immediately.
* If flooding hasn't started, move important items to upper floors of your house.
* If flooding has already started where you are, move to the highest place you can find, like a roof of a house or car. Bring as much food, water, and sheltering blankets as possible.
* Never walk through flood water, especially if it's moving. Hazardous chemicals, sewage, and even wild animals are often in floodwater, and just six inches of moving water can knock you off your feet.
* If you must walk through water to escape, walk where the water is still. Never touch electrical equipment if you are standing in water, or even if you're wet.
* If water is quickly rising while you're in your car, leave your vehicle and move to higher ground, like a hill or bridge.

After a flood
* If you've evacuated your house, return only after you're given the all-clear from officials.
* If you stayed put, check your house for damage to electrical systems and appliances. Get rid of any food that might be contaminated from floodwater (or because it's been unrefrigerated for awhile).
* Check your home for wild animals, especially snakes. They can get washed into your home with the floodwater.
* Ask an adult before you use water to brush your teeth, make food, or even wash your hands. Flooding can contaminate water and make you sick.
Learn more about floods at National Geographic.
Flood safety tips from the Nat Geo Kids book Extreme Weather by Thomas Kostigen

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Learn about what causes flooding, different types of floods-and how to stay safe.

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They can speed across the ocean as fast as a jet plane, swallow up islands and wipe out villages.

But what causes tsuamis...? Join National Geographic Kids and dive into our tsunami facts to find out!

What causes a tsunami?

Meaning " great harbour wave" in Japanese, tsunamis are sometimes called "tidal waves" but their strength has nothing to do with the tides. About four out of five tsunamis happen within the Ring Of Fire, a zone in the Pacific Ocean where earthquakes and volcanic eruptions frequently take place.

Giant slabs of the Earth's crust, called tectonic plates, grind together. Sometimes, though, the plates get stuck, the pressure builds up and they suddenly slam into a new position. This causes an earthquake. If an earthquake lifts or drops part of the ocean floor, the water above rises and starts spreading across the ocean, causing a tsunami. Underwater landslides or volcanic eruptions can also displace water (cause water to spread across the ocean) and may lead to a tsunami.

How big is a tsunami?

Out in the open ocean, tsunami waves are only about one-metre high because the water is deep. However, as the water becomes shallow, the waves slow down and begin to grow. They can rise 35m or higher - that's the same as a 10-floor block of flats! However, the scariest thing about a tsunami is its wavelength, as this determines how far inland it can travel. Whereas a large wave caused by a storm might have a wavelength of up to 150m, a tsunami could reach up to a fearsome 1,000km!

How fast is a tsunami?

A normal wind wave travels at about 90kmh, but a tsunami can race across the ocean at an incredible 970kmh! Sometimes, before a tsunami hits, there is a huge vacuum effect, sucking water from harbours and beaches. People can see the ocean floor littered with flopping fish and other sea animals. Then a wave blasts onto the shore minutes later, then another and another for two hours or more. There may also be up to one hour between each wave.

Can you predict when a tsunami is coming?

To save lives, scientists established the Pacific Tsunami Warning System, based in Hawaii, in the USA. Its network of detectors can track quakes that may cause a tsunami. These waves can race from one side of the Pacific Ocean to the other in less than a day, so people need to be warned in time to head for higher ground!

What do you think of these tsunami facts? Let us know by leaving a comment, below!

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Tsunami facts: check out the mighty wave! - National Geographic Kids

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They can speed across the ocean as fast as a jet plane, swallow up islands and wipe out villages. But what causes tsuamis...? Join National Geographic Kids and dive into our tsunami facts to find out! Meaning " great harbour wave" in Japanese, tsunamis are sometimes called "tidal waves" but their strength has nothing to do with the tides.

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Learn what causes these deadly storms-and how to stay safe.

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A tornado is a type of storm in which powerful rotating winds form a column, which reaches from a cloud down toward the ground. The winds of a tornado are the strongest on...

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A dark greenish tinge covers the sky, and black storm clouds threaten above. The wind roars loudly while cats hide under couches and dogs start howling. A tornado is forming.

Also known as twisters, tornadoes are violently spinning, funnel-shaped columns of air that stretch from the dark thunderclouds they form in all the way to the ground. The wind from a tornado can top 250 miles an hour-that's faster than a race car! These extreme gusts can rip apart buildings, destroy bridges, flip trains, and send cars flying. They can even tear the bark off trees and suck all the water from a riverbed.

Tornadoes occur all over the planet, but the United States leads the world in the strength and number of storms: About a thousand twisters touch down every year. ( Argentina and Bangladesh are next.) As part of larger U.S. storm systems, they cause about 80 deaths a year and close to $1 billion in damage.

How tornadoes develop

Thunderstorms form when cold, dry air is pushed over warm, humid air. When that warm air rises through the colder air, it causes an updraft, or a change in wind direction.

If winds from the thunderstorm vary greatly in speed or direction, the updraft will begin to rotate. As the rotating updraft draws in more warm air from the moving thunderstorm, its rotation speed increases, and a funnel cloud begins to form. As the twister gains strength, the funnel becomes longer. (The funnel becomes more visible as more dirt and debris is caught in its rotation.) It's most dangerous when it touches the ground.

The most violent tornadoes come from supercells-the name scientists give to large thunderstorms with winds already in rotation. About one in a thousand thunderstorms becomes a supercell, and one in five or six supercells creates a tornado.

For all their power, the average tornado lasts only about 10 minutes, though some can rage for over an hour. Twisters usually die when they move over colder ground or when the clouds above it start to break up.

The Tri-State Tornado of 1925 holds the record for time and distance of a tornado. Named for the three states it hit- Missouri, Illinois, and Indiana -the tornado took three and a half hours to tear through 219 miles.

Where and when tornadoes form

Although tornadoes have been spotted in every U.S. state, many form in a region called Tornado Alley. This zone in the Midwest extends from Texas to Ohio and includes Iowa, Kansas, South Dakota, Oklahoma, and Nebraska.

These states are in the path of warm, moist air traveling from the Gulf of Mexico as well as cool air blowing from the Rocky Mountains. When the warm and cool airstreams meet, tornadoes are likely to form.

Though the storms can happen at any time of the year, tornado season in Texas, Oklahoma, and Kansas occurs in May through early June. In North and South Dakota, Nebraska, Iowa, and Minnesota, tornadoes are more likely to form in June or July.

Tracking tornadoes

During thunderstorms, meteorologists use weather satellites, weather balloons, and buoys to gather data like wind speed and temperature. Then they analyze that data with supercomputers. This helps scientists pinpoint where and when a twister might form, as well as how strong or long-lasting it might be.

If weather conditions are right for a tornado to form, experts issue a tornado watch for a region, like a county or large part of a state. This doesn't mean that a tornado is on the way. But it could be-meteorologists issue the watch so people can be prepared.

When a tornado is spotted or picked up on weather radar, scientists issue a tornado warning for a smaller area, like a town or part of a city. People there are urged to take cover.

Some experts actually drive into areas where storms are forming! Vehicles tricked out with special science equipment measure things like temperature, humidity, and air pressure that's submitted to meteorologists at weather service headquarters. But the information that these "tornado chasers" gather also helps scientists better understand the science of tornados.

Thanks to these tools, meteorologists are now able to quickly predict when and where a tornado will form, giving people in a twister's path more time to seek shelter. For instance, in the 1980s, people only had about a five-minute warning before a tornado hit; by the late 2000s, the warning time grew to 13 minutes.

How to survive a tornado
Before a tornado
* Listen to weather reports for tornado warnings.
* Close all the windows.
* Prepare a safe room. This can be your basement or the lowest room in the center of your house or apartment building, away from outer walls and windows. Window-free closets and bathrooms work well, too.
* Fill the safe room with blankets, pillows, sleeping bags, and your family emergency kit (water, food, flashlight, and radio).
* Have an emergency safety plan. If you live in a trailer or mobile home, make sure you know where to go to evacuate.
During a tornado
* Stay inside-never attempt to watch or chase a tornado.
* Do not go near windows. It's not the tornado itself that causes most injuries; it's the flying debris-or the windows they crash through-that cause most injuries.
* Cover yourself with the pillows, blankets, and sleeping bags. If there's a sturdy piece of furniture, like a table, crawl under it.
* Cover your head and neck with your arms.
* If you're caught outside and can't find shelter, look for a ditch, gulley, or just a flat piece of ground away from trees and cars. Lie down as flat as you can and cover your head and neck with your arms. (Do not try this under a bridge or overpass.)
After a tornado
* Do not leave your shelter until local authorities give the OK. Follow their instructions.
* If you go outside, watch where you step-dangerous debris can be anywhere.
* Continue to monitor tornado reports. Sometimes more than one can whip up in the same place.
Learn more about tornadoes at National Geographic.
Tornado safety tips from the Nat Geo Kids book Extreme Weather by Thomas Kostigen and How to Survive Anything by Rachel Buchholz

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Find out what causes these deadly twisters-and how to stay safe.

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VOLCANO SAFETY

Volcanoes blast hot, solid and molten rock and gases into the air. As a result, ash can fall hundreds of miles downwind of a volcano. If you live near a volcano, active or dormant, be prepared to follow instructions from your local emergency officials by listening to the radio and television. Volcanoes occur on the West Coast, in Alaska and in Hawaii.

PLAN FOR A VOLCANO:

Have a disaster plan.

Know whether or not you are at risk for danger.

Be prepared for mudslides, flash floods, earthquakes, ash falling, acid rain and tsunamis.

Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing, dust mask, goggles and sturdy shoes.

Know evacuation routes.

DURING A VOLCANO:

Follow the evacuation order issued by authorities.

Avoid areas downwind and river valleys downstream of the volcano.

If your caught indoors, close all windows and doors, put machinery inside a barn, and bring animals inside.

If you're trapped outdoors, seek shelter indoors. If you're caught in falling rocks, roll into a ball and protect your head. If you're caught near a stream, be aware of mudflows. Move to higher ground.

Protect yourself when ash falls. Wear long-sleeved shirts and long pants. Use goggles to protect your eyes. Wear a dust mask and keep car engines off.

AFTER A VOLCANO:

Cover you mouth and nose. Volcanic ash can irritate your respiratory system.

Wear goggles and protect your eyes.

Keep your skin covered.

Clear roofs of ash. The ash is very heavy and can cause the building to collapse.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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Hail Safety and Readiness Tips - Nationwide

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Nationwide offers instant auto insurance online in just a matter of minutes. See how you can find auto insurance discounts, get a quote, and more.

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All thunderstorms produce lightning and are dangerous. If you hear the sound of thunder, then you are in danger from lightning. Lightning kills between 75 to 100 people each year and being outdoors in the most dangerous place to be. Always listen to the radio and television for the latest information and instructions for your area.

A THUNDERSTORM WATCH means a thunderstorm is possible for your area.

A THUNDERSTORM WARNING means a thunderstorm is taking place in your area.

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. It's a great conductor of electricity. Swimming, wading, snorkeling and scuba diving are not safe. Also, don't stand in puddles.

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.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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Pour yourself a glass of water and take a sip. Did you know that the water you've just swallowed is the same water that wooly mammoths, King Tutankhamun and the first humans drank? That's because Earth has been recycling water for over 4 billion years!

The world's water moves between lakes, rivers, oceans, the atmosphere and the land in an ongoing cycle called - you guessed it! - the water cycle. As it goes through this continuous system, it can be a liquid (water), a gas (vapour) or a solid (ice).

So, are all you budding young geographers ready to learn some splashing new facts? Then join NG KiDS as we take a look at the different stages of the wonderful water cycle...

Energy from the sun heats up the surface of the Earth, causing the temperature of the water in our rivers, lakes and oceans to rise. When this happens, some of the water "evaporates" into the air, turning into a gas called " vapour". Plants and trees also lose water to the atmosphere through their leaves. This process is known as " transpiration ".

As water vapour rises up high into the sky, it cools and turns back into a liquid, forming clouds. This process is called " condensation ". Currents high up in the air move these clouds around the globe.

The water cycle is also known as the "hydrologic cycle".

Precipitation

When too much water has condensed, the water droplets in the clouds become too big and heavy for the air to hold them. And so they fall back down to Earth as rain, snow, hail or sleet, a process known as " precipitation ".

Collection

The fallen precipitation is then "collected" in bodies of water - such as rivers, lakes and oceans - from where it will eventually evaporate back into the air, beginning the cycle all over again. How it is collected, depends on where it lands...

Some will fall directly into lakes, rivers or the sea, from where it will evaporate and begin the cycle all over again.

If the water falls on vegetation, it may evaporate from leaves back into the air, or trickle down to the ground. Some of this water may then be taken up by the plant roots in the earth.

In cold climates, the precipitation may build up on land as snow, ice or glaciers. If temperatures rise, the ice will melt to liquid water and then soak into the ground, or flow into rivers or the ocean.

Water that reaches land directly may flow across the ground and collect in the oceans, rivers or lakes. This water is called " surface run-off ". Some of the precipitation will instead soak (or "infiltrate") into the soil, from where it will slowly move through the ground until eventually reaching a river or the ocean.

And there you have it, gang - the ongoing water cycle!

Water can change from a solid to a gas, without becoming a liquid first. Through this process of "sublimation" our planet"s ice can evaporate directly into the air without melting!

Be sure to check out our water conservation primary resource. Great for teachers, homeschoolers and parents alike, show children 25 ways to help keep our oceans, rivers and streams clean...

Illustration: Getty Images UK

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The Water Cycle! - National Geographic Kids

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Earth has been recycling water for 4 billion years! Learn about the water cycle right here at NG Kids with clear diagrams and pictures.

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The Water Cycle for Kids | Learn all about the water cycle

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Liquid water is present in seas, oceans, rivers, and lakes. When it is heated, liquid water forms a gas, or vapor. The process by which liquid water becomes a vapor is called evaporation. When water in a puddle is warmed by the sun it evaporates into invisible vapor. It does not disappear; it still exists, just in a different state.

When water vapor in the atmosphere cools, or the air can no longer hold the amount of water vapor it contains, the water returns to a liquid state, such as rain. The process by which water vapor becomes a liquid is called condensation. Condensation is the opposite, or reverse, of evaporation.

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Liquid water is present in seas, oceans, rivers, and lakes. When it is heated, liquid water forms a gas, or vapor. The process by which liquid water becomes a vapor is called evaporation. When water in a puddle is warmed by the sun it evaporates into invisible vapor.