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Hurricanes are severe tropical storms that form in the southern Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and in the eastern Pacific Ocean. They collect heat and energy through contact with warm ocean waters and then move toward land. Evaporation from the ocean water increases their power. Hurricanes rotate in a counter-clockwise direction around an "eye," which is the center of the hurricane.

Hurricanes have winds at least 74 miles per hour. When hurricanes come onto land, their heavy rain, strong winds, and large waves can damage buildings, trees, and cars. Storm surge is when rising water moves inland, or away from the coastline. It's very dangerous.

Words to Know

Inland - Away from the coastline.

Am I at Risk?

What Can I Do?

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After

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Did you know?

Hurricanes can also affect areas greater than 100 miles away from the coastline. People who live inland are also at risk for wind, thunderstorms, tornadoes, and flooding.

Helpful Links

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Words to Know Am I at Risk? What Can I Do? Learn More

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Words to Know Am I at Risk? What Can I Do? Learn More

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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.

Activities

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

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Of all Earth's natural hazards, tsunamis are among the most infrequent. Major tsunamis do not happen often, but when they do, they can have a significant impact on life and property. Even small tsunamis, which are more frequent, can cause loss of life, injuries, and considerable damage.

But there are things communities can do before, during, and after a tsunami that can save lives and minimize losses.

Tsunami impacts can vary greatly from one community to the next depending on their local bathymetry and topography. So to prepare for a tsunami, coastal communities should conduct hazard assessments to understand how tsunamis of different sizes and sources (location and type) might affect them.

A hazard assessment includes using computer models and information from past tsunamis to identify and map the areas likely to be flooded during a tsunami and by how much.

Since the 1990s, Hawaii has recognized April as Tsunami Awareness Month.

Communities can use the resulting tsunami hazard zone maps to determine where people and other important community assets (e.g., buildings, facilities, bridges, schools, hospitals) are at risk so they can decide where to focus preparedness, response, and mitigation efforts.

Communities that understand their tsunami risk are better prepared to protect the public in the event of a tsunami. Protective measures include:

Planning and practicing for response to tsunamis;

Warning the public;

Establishing, marking, and publicizing evacuation routes; and

Educating the public (residents and visitors) about tsunamis and tsunami safety before a tsunami strikes.

The first tsunami vertical structure in the United States: Ocosta Elementary School, Westport, Washington. The building is designed to withstand an earthquake and has a flat roof over the gym to accommodate up to 1,000 students and community members from a resulting tsunami. Source: Pete Eckert, Eckert & Eckert Photography

Other ways to prepare for and mitigate the potential impacts of a tsunami emphasize thoughtful land-use planning and building design in tsunami hazard zones and include the following:

Improving evacuation routes

Building tsunami evacuation structures

Limiting new development in tsunami hazard zones

Designing, siting, and building structures to minimize tsunami damage

Adopting building codes that address tsunamis

Protecting and strengthening existing structures and infrastructure that if damaged would negatively affect response and recovery

Moving important community assets and vulnerable populations out of tsunami hazard zones

Planning for post-tsunami recovery

In the United States, much of the tsunami preparedness and mitigation work is conducted through two programs:

The National Tsunami Hazard Mitigation Program is a federal/state partnership led by NOAA that also includes the Federal Emergency Management Agency, the U.S. Geological Survey, and 28 U.S. states and territories. Through collaboration, coordination, and support to partner states and territories, the program focuses on three key functions: hazard assessment, warning guidance, and mitigation.

The NWS TsunamiReady® program is a voluntary community recognition program that helps communities minimize the risk posed by tsunamis through better risk assessment, planning, education, and warning communications. The Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific, and Cultural Organization modeled their International Tsunami Ready program on the NWS program.

To be recognized as TsunamiReady and display this sign, a community must have implemented the activities established in the TsunamiReady Guidelines.

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Tsunami Preparedness and Mitigation: Communities

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Of all Earth's natural hazards, tsunamis are among the most infrequent. Major tsunamis do not happen often, but when they do, they can have a significant impact on life and property. Even small tsunamis, which are more frequent, can cause loss of life, injuries, and considerable damage.

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What a Tsunami is, what it looks like, how it generates damage. 

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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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Tsunami is a Japanese word that means "harbor wave." It is a large wave caused by movements in Earth's outer layer, or crust, which move ocean water. For example, an earthquake or a volcano in the ocean could cause a tsunami.

Earth's crust is made up of pieces called tectonic plates. An earthquake happens when these plates push against each other so hard that one of them slips or breaks. Imagine leaning against a friend. If you push against each other harder and harder, one or both of you will fall over. When Earth's plates push against each other, they can move a lot.

If an earthquake happens in the ocean, a large piece of Earth's crust can be thrust upward or slip from side to side. The movement of a large chunk of Earth displaces the water above it, meaning it takes up the space where the water used to be. So where does the water go? It ripples out from the earthquake in waves.

This can also happen if a volcano erupts in the ocean. The lava flowing out of the volcano displaces the water around it. That water can turn into a large wave.

If the earthquake or volcano is very big, then the wave can be very big, too. Big tsunamis usually begin in the deep ocean, where a large volume of water can be displaced. As the wave moves closer to the shore, it grows taller as the ocean becomes shallower. If the water recedes-or moves away from the coast-after an earthquake, a big tsunami may be on its way.

Tsunamis can be hundreds of feet tall, and they travel very fast. This means they can be dangerous even for people who aren't on the beach. Tsunamis can be extremely destructive and can knock down whole buildings.

But not all earthquakes or volcanic eruptions cause tsunamis. Whether a tsunami forms can depend on a lot of things. The shape of the ocean floor can determine if a tsunami happens. So can the distance and direction of the earthquake.

If there's a chance a tsunami is on its way, you don't want to be near the coast. So how can we tell if a tsunami is coming? We use satellites!

MISR (the Multi-angle Imaging SpectroRadiometer) is a NASA tool that watches for tsunamis from space. It has nine cameras, all pointed in slightly different directions. As the satellite passes overhead, it takes nine pictures of the same spot from different angles.

MISR can see sunlight reflecting off ripples and waves. Satellites that look straight down cannot see these ripples.

These images help scientists understand how tsunamis work. The more we learn about tsunamis, the better we can predict where, when and how strong a tsunami will be. That way, people can have enough warning to get away and stay safe.

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Tsunami is a Japanese word that means "harbor wave." It is a large wave caused by movements in Earth's outer layer, or crust, which move ocean water. For example, an earthquake or a volcano in the ocean could cause a tsunami. Earth's crust is made up of pieces called tectonic plates.

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Flooding is a coast-to-coast threat to some part of the United States and its territories nearly every day of the year. This site is designed to teach you how to stay safe in a flood event. If you know what to do before, during, and after a flood you can increase your chances of survival and better protect your property. For instance, it is vital to know what to do if you are driving and hit a flooded road. Here you will find an interactive flood map, information describing the different types of flooding and educational material. You will also learn how the National Weather Service keeps you aware of potentially dangerous flooding situations through alerts and warnings.

Learn how to better protect yourself and your family by reading our flood survivor stories. If you, or someone you know, have been a victim of a flood, please share your story so we can prevent others from becoming a victim. When you write, please note that NWS has permission to use your story and, if possible, let us know the town and state you were in and the year the event took place.

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Flooding is a coast-to-coast threat to some part of the United States and its territories nearly every day of the year. This site is designed to teach you how to stay safe in a flood event. If you know what to do before, during, and after a flood you can increase your chances of survival and better protect your property.

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Flooding is when a lot of water overflows onto land that is normally dry. It is the most common natural-weather event. Flooding can happen during heavy rains, when rivers overflow, when ocean waves come on the shore, when snow melts too fast, or when dams or levees break. Flooding may be only a few inches of water, or it may cover a house to the rooftop. Floods that happen very quickly are called flash floods. Floods can cause power outages, disrupt transportation, damage buildings, and create landslides.

Words to Know

Am I at Risk?

What Can I Do?

Before

During

After

Learn More

Did you know?

Flooding can wash out walkways, roads, and fields, making them impossible to detect under flood water. Do not walk or ride in a car through water. It might be deeper than you think! A foot of water can sweep a vehicle off the road. Stay away from moving water!

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Words to Know Am I at Risk? What Can I Do? Learn More

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https://www.sciencekids.co.nz/sciencefacts/weather/floods.html

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Flood Facts For Kids

Check out our flood facts for kids and learn a range of interesting information about floods.

Did you know that floods can be an important natural process for farming? Understand how floods happen, the different types of flood events and much more with our flood facts for kids.

Depending on their type, floods can develop very slowly over time after extensive rains or in just a few minutes, very quickly, without any sign of rain.

There are many types and ways floods can occur, including, due to overflowing rivers, due to extreme coastal events, by natural or artificial ground saturation from excess rainfall, or by catastrophic failure in infrastructure.

Flash floods are extreme versions of a river flooding event. They can occur very quickly, often without warning and with little or no excessive rainfall. Flash floods are the result of a river blockage either natural or artificial (such as a landslide, glacier, or dam) giving way and releasing a massive amount of built up water.

Areal or urban flooding occurs when low-lying impenetrable ground becomes saturated as rainfall cannot run off as quickly as the accumulation of water. For example, on natural drought hardened or frozen farmland, or on concrete paving.

Floods can damage bridges, roads and other transport links. Infrastructure such as buildings, cars and houses can be left saturated or completely taken by the waters. While sewage systems and power grids can be destroyed.

After floodwaters recede, land can be contaminated with hazardous material, such as building debris, fuel and untreated sewage. Residents are often left without power or clean drinking water which can lead to outbreaks of diseases.

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Flood Facts for Kids - Interesting Information about Floods

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Flood Facts For Kids Check out our flood facts for kids and learn a range of interesting information about floods. Did you know that floods can be an important natural process for farming? Understand how floods happen, the different types of flood events and much more with our flood facts for kids.

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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.