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Drought Conditions in SW America

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Problems hurricanes cause

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Learn How they Form

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ProQuest __ SIRS Discoverer _ Hurricane Hunters

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South Asia Earthquake

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ProQuest __ SIRS Discoverer _ Earthquake!

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ProQuest __ SIRS Discoverer _ Windmills Fixed the Floods!

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What are earthquakes? Get a new perspective on these powerful phenomena with this collection of videos and infographics co-presented by the California Academy of Sciences and KQED. You'll learn why earthquakes happen, how they've shaped the Bay Area, and what you can do to prepare for the next one.

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Wicked Weather - Copyright (c) 2004 National Geographic Society (CONTRACT)_ProQuest

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How weathermen calculate hurricane strength

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Summary:  "Hundreds of earthquakes shake our planet each day. We can't stop them, but we are learning how to live with them." (National Geographic Explorer!) Learn how people try to stay safe during earthquakes and tsunamis.

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Fun Kids - the UK's children's radio station

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Flooding is something which can happen as a result of changes to the climate and here in the UK it's becoming more common.

A bit of rain is something we're used to in this country. Sometimes it's fun to get your wellies on and jump in some puddles.

Rain is important for life - providing water to drink and keep clean, and helping crops and plants to grow. People also like to live near water - it's relaxing and a great source of fun.

But too much rainwater can cause very serious problems - causing rivers to overflow and flood the surrounding areas, filling houses, schools and shops with water. You can imagine how scary that might be and how much damage would be done if that happened in your neighbourhood. You might even have to leave your home to stay somewhere else.

Climate explorers are very interested in studying rainfall and flooding to help us prepare for when these things happen - and to help prevent them causing damage.

It's something that's becoming more important. Rising global temperatures may cause heavier rainfall events, as well as sea levels to rise. So flooding is something that's not going to go away.

Kate

Hi - I'm Kate and I'm a flood scientist.

Floods kill more people than anything else on the planet and are something which can affect us here in the UK. We can't just hope they don't happen - we have to accept that they are a part of life, and do our best to reduce the impact they have.

Flooding isn't just becoming more frequent - but the levels of floodwater are becoming higher too. In 2015 flooding in Cumbria broke some of our strongest flood defences. My job is to try to work out what will happen to rivers when there is a lot of rainfall. If we know where the river will overflow then we can take measures to prevent damage to homes.
Great to know there is something we can do. But how can you tell where the overflows will be?
We make computer models of rivers and chuck a load of 'virtual' water into them. We keep going until the water starts to jump out.

When there is a real flood, we collect real data to see if our models were correct - whether the areas with the most flooding match what our computer model predicted.
Sounds like you get rather wet!
Well luckily we have a drone - a small flying robot - which uses sensors like infrared and thermal imaging to take measurements. Ours is called Firefly. It flies above the areas affected to collect the data.
Even though we can't easily prevent natural disasters like flooding, it's good to know that climate explorers are working hard to help us limit the damage they can do.
Next, we'll be looking at how the animals can help us understand changes to the climate... click here!
You can hear Marina Ventura's Climate Explorers weekdays from 5pm on Fun Kids!
Get the series on your phone or tablet and listen whenever you like - at home or in the car!

...or you can listen here:

Additional support thanks to Liverpool John Moores University, Manchester Metropolitan University, Met Office, and King's College London.

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Learning about the climate from flooding - Fun Kids - the UK's children's radio station

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Flooding is something which can happen as a result of changes to the climate and here in the UK it's becoming more common. A bit of rain is something we're used to in this country. Sometimes it's fun to get your wellies on and jump in some puddles.

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Smash: When continents collide! | Brains on! A podcast for kids & curious adults

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How are mountains made? What causes an earthquake? How does hot lava come bubbling up? The answer in each case is...tectonic plates!

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children kids podcast ios apps education science discovery sharing

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Kids Listen: Thunder, lightning and tornadoes: Where do they come from?

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From Brains On! Science podcast for kids. There are some basic ingredients to make thunderstorms and tornadoes. We'll find out what they are - and how to observe these powerful and amazing storms safely.

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The Hurricane of the Future - Tumble Science Podcast for Kids

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Why are hurricanes so powerful? Every year, monster storms develop in the Atlantic Ocean from June until November. It seems like they come out of nowhere. But scientists are working to predict them months, years, and even decades before they start. We'll discover what makes hurricanes so destructive, and why they might become even more intense in the future.

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Severe Weather 101

Tornado Basics

What is a tornado?

A tornado is a narrow, violently rotating column of air that extends from a thunderstorm to the ground. Because wind is invisible, it is hard to see a tornado unless it forms a condensation funnel made up of water droplets, dust and debris. Tornadoes can be among the most violent phenomena of all atmospheric storms we experience.

Read more about NSSL's tornado research here.

Where do tornadoes occur?

Tornadoes occur in many parts of the world, including Australia, Europe, Africa, Asia, and South America. Even New Zealand reports about 20 tornadoes each year. Two of the highest concentrations of tornadoes outside the U.S. are Argentina and Bangladesh.

How many tornadoes occur in the U.S. each year?

About 1,200 tornadoes hit the U.S. yearly. Since official tornado records only date back to 1950, we do not know the actual average number of tornadoes that occur each year. Plus, tornado spotting and reporting methods have changed a lot over the last several decades, which means that we are observing more tornadoes that actually happen.

Where is Tornado Alley?

Tornado Alley is a nickname invented by the media to refer to a broad area of relatively high tornado occurrence in the central United States. Various "Tornado Alley" maps look different because tornado occurrence can be measured many ways: by all tornadoes, tornado county-segments, strong and violent tornadoes only, and databases with different time periods.

However, the idea of a "tornado alley" can be misleading. The U.S. tornado threat shifts from the Southeast in the cooler months of the year, toward the southern and central Plains in May and June, and the northern Plains and Midwest during early summer. Tornadoes can occur and have been reported in all fifty states!

Please remember, violent tornadoes do happen outside "Tornado Alley" every year.

When are tornadoes most likely?

Tornado season usually refers to the time of year the U.S. sees the most tornadoes. The peak "tornado season" for the southern Plains (e.g., Texas, Oklahoma, and Kansas) is from May into early June. On the Gulf coast, it is earlier in the spring. In the northern Plains and upper Midwest (North and South Dakota, Nebraska, Iowa, Minnesota), tornado season is in June or July. But, remember, tornadoes can happen at any time of year. Tornadoes can also happen at any time of day or night, but most tornadoes occur between 4-9 p.m.

What is the difference between a Tornado WATCH and a Tornado WARNING?

A Tornado WATCH is issued by the NOAA Storm Prediction Center meteorologists who watch the weather 24/7 across the entire U.S. for weather conditions that are favorable for tornadoes and severe weather. A watch can cover parts of a state or several states. Watch and prepare for severe weather and stay tuned to NOAA Weather Radio to know when warnings are issued.

A Tornado WARNING is issued by your localNOAA National Weather Service Forecast Office meteorologists who watch the weather 24/7 over a designated area. This means a tornado has been reported by spotters or indicated by radar and there is a serious threat to life and property to those in the path of the tornado. A tornado warning indicates that you should ACT NOW to find safe shelter! A warning can cover parts of counties or several counties in the path of danger.

Watchthis Youtube video for a great explanation!

How is tornado strength rated?

To determine the strength of a tornado, experts examine the damage it caused. From this information, we can estimate the wind speeds. An "Enhanced Fujita Scale" was implemented by the National Weather Service in 2007 to rate tornadoes in a more consistent and accurate manner. The EF-Scale takes into account more variables than the original Fujita Scale (F-Scale) when assigning a wind speed rating to a tornado, incorporating 28 damage indicators such as building type, structures and trees. For each damage indicator, there are 8 degrees of damage ranging from the beginning of visible damage to complete destruction of the damage indicator. The original F-scale did not take these details into account. The original F-Scale historical data base will not change. An F5 tornado rated years ago is still an F5, but the wind speed associated with the tornado may have been somewhat less than previously estimated. A correlation between the original F-Scale and the EF-Scale has been developed. This makes it possible to express ratings in terms of one scale to the other, preserving the historical database.

How do tornadoes form?

The truth is that we don't fully understand. The most destructive tornadoes occur from supercells, which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone. (Supercells can also produce damaging hail, severe non-tornadic winds, frequent lightning, and flash floods.) Tornado formation is believed to be dictated mainly by things which happen on the storm scale, in and around the mesocyclone. Recent theories and results from the VORTEX2 program suggest that once a mesocyclone is underway, tornado development is related to the temperature differences across the edge of downdraft air wrapping around the mesocyclone. Mathematical modeling studies of tornado formation also indicate that it can happen without such temperature patterns; and in fact, very little temperature variation was observed near some of the most destructive tornadoes in history on 3 May 1999. We still have lots of work to do.

What do storm spotters look for when trying to identify a tornado or a dangerous storm?

Inflow bands are ragged bands of low cumulus clouds extending from the main storm tower usually to the southeast or south. The presence of inflow bands suggests that the storm is gathering low-level air from several miles away. If the inflow bands have a spiraling nature to them, it suggests the presence of rotation.

Thebeaver's tail is a smooth, flat cloud band extending from the eastern edge of the rain-free base to the east or northeast. It usually skirts around the southern edge of the precipitation area. It also suggests the presence of rotation.

Awall cloud is an isolated cloud lowering attached to the rain-free base of the thunderstorm. The wall cloud is usually to the rear of the visible precipitation area.

A wall cloud that may produce a tornado can exist for 10-20 minutes before a tornado appears, but not always. A wall cloud may also persistently rotate (often visibly), have strong surface winds flowing into it, and may have rapid vertical motion indicated by small cloud elements quickly rising into the rain-free base.

As the storm intensifies, the updraft draws in low-level air from several miles around. Some low-level air is pulled into the updraft from the rain area. This rain-cooled air is very humid; the moisture in the rain-cooled air quickly condenses below therain-free base to form the wall cloud.

Therear flank downdraft (RFD) is a downward rush of air on the back side of the storm that descends along with the tornado. The RFD looks like a "clear slot" or "bright slot" just to the rear (southwest) of the wall cloud. It can also look like curtains of rain wrapping around the cloud base circulation. The RFD causes gusty surface winds that occasionally have embedded downbursts. The rear flank downdraft is the motion in the storm that causes the hook echo feature on radar.

Acondensation funnel is made up of water droplets and extends downward from the base of the thunderstorm. If it is in contact with the ground it is a tornado; otherwise it is a funnel cloud. Dust and debris beneath the condensation funnel confirm a tornado's presence.

Be careful! Tornadoes can form and be in contact with the ground without a fully condensed funnel!

An excellent comprehensive list of questions and answers about tornadoes can be found here:http://www.spc.noaa.gov/faq/tornado/

NSSL is working to simulate storms that produce tornadoes in computer models to better understand how they form and behave.

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Basic information about tornadoes, from the NOAA National Severe Storms Laboratory.

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Take shelter, gang - because here at National Geographic Kids, we're entering the eye of the storm with ten tornado facts!

Check out our ten top facts about tornadoes...

1) Tornadoes - also known as "twisters" - are violently rotating columns of air that reach from a storm cloud to the earth's surface.

2) The winds of a tornado can reach speeds of up to 480km per hour - that's strong enough to peel the roofs off houses, uproot trees and hurl heavy objects, such as cars, hundreds of metres!

3) Tornadoes come in different shapes and sizes. Some may appear as wide funnel-shaped clouds, others as thin rope-like swirls stretching from the ground to the sky.

4) The duration of tornadoes, and the distance they travel, varies. Most last less than ten minutes and travel five to ten kilometres before disappearing. In extreme cases, however, they can last several hours and cross distances over 150km!

5) Tornadoes are measured using the Fujita Scale (or F-scale), ranging from F0 to F5, with F5 being the strongest and most destructive.

6) The deadliest tornado ever recorded was in Bangladesh in 1989. As it travelled through the Dhaka region of the country, more than 20 villages were destroyed and around 1,300 people were killed.

7) Most of the world's tornadoes occur in the United States in what's known as Tornado Alley. Stretching from west Texas to North Dakota, this area can see more than 200 tornadoes each year!

8) If a tornado occurs over water, it's called a waterspout.

9) Not all tornadoes are easy to see. In fact, they can be invisible until they pick up dust and debris, or a cloud forms within the spinning funnel.

10) The formation of a tornado is so complex that scientists still don't completely understand it. And what's more, the unpredictability of tornadoes makes them difficult - and dangerous - to study. A tornado will demolish everything in its path, including measuring equipment. And so, the secrets behind this incredible force of nature are yet to be discovered...

Photos: Getty Images UK

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Tornado Facts! - National Geographic Kids

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Find out ten facts about tornadoes here at National Geographic Kids. How powerful are tornadoes? How are they measured? Find out all about these powerful forces of nature!

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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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Explore National Geographic. A world leader in geography, cartography and exploration.

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What damage can a tornado do?

This photograph from 2007 shows the damage a tornado can do!

Some tornadoes have caused terrible damage and loss of life. One of the worst was in March 1925 when a tornado hit the town on Annapolis in Missouri, USA.

It was a calm sunny afternoon and children were playing marbles in the street. The sky was clear and blue. Suddenly on the horizon people saw a black cloud shaped like an ice-cream cone. It raced down on the town at terrific speed, bringing with it a wind of 150 miles an hour.

With a deafening roar the tornado tore through the streets, leveling everything in its path. Solid stone buildings were torn apart, passenger trains were turned over and smashed, fifty cars were swept up and carried over the rooftops.

The tornado's path was less than 250 yards wide but it left a terrible scene behind it, with 823 people killed and nearly 3,000 injured.

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Tornadoes - Tornado Facts - Tornadoes for Kids - Weather Facts for kids

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This photograph from 2007 shows the damage a tornado can do! Some tornadoes have caused terrible damage and loss of life. One of the worst was in March 1925 when a tornado hit the town on Annapolis in Missouri, USA. It was a calm sunny afternoon and children were playing marbles in the street.

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Tornado Facts For Kids

Enjoy our fun tornado facts for kids! Learn what tornadoes are, how fast they spin, how far they can travel, where most tornadoes occur, the difference between an F0 tornado and an F5 tornado, what a waterspout is and much more.

Read on to check out our wide range of information on twisters.

A tornado is a rapidly spinning tube of air that touches both the ground and a cloud above.

Tornadoes are sometimes called twisters.

Not all tornadoes are visible but their high wind speeds and rapid rotation often form a visible funnel of condensed water.

The Fujita Scale is a common way of measuring the strength of tornadoes. The scale ranges from F0 tornadoes that cause minimal damage through to F5 tornadoes which cause massive damage.

Most tornadoes have wind speeds less than 100 miles per hour (161 kilometres per hour).

Extreme tornadoes can reach wind speeds of over 300 miles per hour (483 kilometres per hour).

Most tornadoes travel a few miles before exhausting themselves.

Extreme tornadoes can travel much further, sometimes over 100 miles (161kilometres).

The Tri-State Tornado that travelled through parts of Missouri, Illinois and Indiana in 1925 left a path of destruction over 219 miles (352 kilometres) long.

The Tri-State Tornado was the deadliest tornado in US history, killing 695 people.

The USA averages around 1200 tornadoes every year, more than any other country.

The majority of these tornadoes occur in a geographically unique area nicknamed 'Tornado Alley'.

US States most often hit by tornadoes include Texas, Kansas, Oklahoma and Florida.

In 1989 the deadliest tornado ever recorded in the world killed around 1300 people in Bangladesh.

In the southern hemisphere tornadoes usually rotate in a clockwise direction.

In the northern hemisphere tornadoes usually rotate in a counterclockwise direction.

A tornado that occurs over water is often called a waterspout.

Weather radars are used to detect tornadoes and give advanced warning.

Basements and other underground areas are the safest places to seek refuge during a tornado. It is also a good idea to stay away from windows.

Make a tornado in a bottle or watch some amazing tornado video footage.

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Fun Tornado Facts for Kids - Interesting Information about Twisters

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Tornado Facts For Kids Enjoy our fun tornado facts for kids! Learn what tornadoes are, how fast they spin, how far they can travel, where most tornadoes occur, the difference between an F0 tornado and an F5 tornado, what a waterspout is and much more.

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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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In this video from the National Hurricane Center, your students can learn from FEMA about the importance of having a plan for when a hurricane strikes, and where the best place to go to start working on their plan is.

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In this video from the National Hurricane Center, your students can learn from FEMA about the importance of having a plan for when a hurricane strikes, and where the best place to go to start working on their plan is.

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Hurricane | The Dr. Binocs Show | Educational Videos For Kids

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On August 29, 2005, Hurricane Katrina struck New Orleans, Louisiana, and the surrounding area (see map). Katrina was one of the deadliest storms in U.S. history. More than 1,800 people were killed, mostly in New Orleans. Property damage in Louisiana, Mississippi, and Alabama totaled more than $100 billion.

Darlene Alexander, who lived in New Orleans in 2005, remembers hearing the first storm warnings. She thought they were false alarms like others in the past. But when the Governor of Louisiana at the time, Kathleen Blanco, urged residents to leave, Alexander decided to act quickly. She bought a car at a dealership that was already boarding up its windows. The morning before the storm, she drove with her two sons, Austin and Justin, to Shreveport, Louisiana.

"I grabbed a bag of pictures," Alexander recalls, "and a couple of outfits. My son Austin grabbed a bunch of tennis shoes. I remember fussing at him because he took so many shoes. But then, when we all needed clothes, he was the only one who didn't need shoes."
A "TRAUMATIC" TIME
Like most people who fled New Orleans, Alexander didn't know that 80 percent of the city would be flooded. When the levee system (walls that keep out water) collapsed, more than 100,000 homes and businesses were destroyed. Hundreds of thousands of people were displaced.

Alexander decided to relocate to Shreveport so that she could raise her sons "in a safe environment." She now teaches math at my school, Caddo Middle Magnet. Her son Austin, who was 13 at the time of the storm, says that the opportunity to start a new life in a new city "was probably one of the best things that ever happened" to him and his family.

Charlene Gordon-Cannon, also a resident of New Orleans in 2005, describes the weeks and months after the storm as "traumatic, emotional, and stressful." Her family's home was flooded, and many of their possessions were lost. After the family evacuated, Gordon-Cannon had to return to New Orleans for work. All of the turmoil made her young daughter, Nila, feel "stressed out and scared."
TRYING TO REBUILD
Televised news reports of the storm exposed racial inequality in New Orleans to the world. Many African Americans in poor communities did not have the resources to protect their families and homes, or even to leave the city before the storm hit.

Today, the struggle to rebuild New Orleans continues. Homes are being built in the Lower Ninth Ward, a neighborhood that was nearly wiped out by the storm. Tech companies are bringing much-needed business to the city. Yet urban expert Roberta Brandes Gratz has found that many African Americans are still being left behind. New Orleans, she says, "is a tale of two cities."

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On August 29, 2005, Hurricane Katrina struck New Orleans, Louisiana, and the surrounding area (see map). Katrina was one of the deadliest storms in U.S. history. More than 1,800 people were killed, mostly in New Orleans. Property damage in Louisiana, Mississippi, and Alabama totaled more than $100 billion.

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Katrina: Five Years Later | Scholastic.com

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On the fifth year anniversary of Hurricane Katrina, one of the worst disasters to hit the Gulf, President Obama visited New Orleans to support the city as it faces new challenges.

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Hurricanes only form over really warm ocean water of 80°F or warmer. The atmosphere (the air) must cool off very quickly the higher you go. Also, the wind must be blowing in the same direction and at the same speed to force air upward from the ocean surface. Winds flow outward above the storm allowing the air below to rise. Hurricanes typically form between 5 to 15 degrees latitude north and south of the equator. The To learn more about hurricanes, 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. Have a NOAA weather radio handy with plenty of batteries, so you can listen to storm advisories. Have some cash handy as well, because following a hurricane, banks and ATMs may be temporarily closed. Make sure your car is filled with gasoline. Hurricanes

What is a hurricane?
A hurricane is a huge storm! It can be up to 600 miles across and have strong winds spiraling inward and upward at speeds of 75 to 200 mph. Each hurricane usually lasts for over a week, moving 10-20 miles per hour over the open ocean. Hurricanes gather heat and energy through contact with warm ocean waters. Evaporation from the seawater increases their power. Hurricanes rotate in a counter-clockwise direction around an "eye" in the Northern Hemisphere and clockwise direction in the Southern Hemisphere. The center of the storm or "eye" is the calmest part. It has only light winds and fair weather. When they come onto land, the heavy rain, strong winds and large waves can damage buildings, trees and cars.

>Click Here to get your very own Hurricane Tracking Chart.

How do hurricanes form?
Coriolis Force is needed to create the spin in the hurricane and it becomes too weak near the equator, so hurricanes can never form there.

What is storm surge?
Storm surges are frequently the most devastating element of a hurricane. As a hurricane's winds spiral around and around the storm, they push water into a mound at the storm's center. This mound of water becomes dangerous when the storm reaches land because it causes flooding along the coast. The water piles up, unable to escape anywhere but on land as the storm carries it landward. A hurricane will cause more storm surge in areas where the ocean floor slopes gradually. This causes major flooding.
As you watch the storm-surge animations, notice the effect that the physical geography of each coastline has on storm surge. Also, note the waves on top of the ocean's surface. Wind, waves, and sea-level rise all contribute to storm-surge damage.

Shallow-Water Coastline

Deep-Water Coastline

With technology the way it is, there are computer models that allow forecasters to predict the amount of storm surge that will affect a coastal area. These are called Slosh Models and take into account a storm's strength, its path, how the ocean shallows, and the shape of the land. Then it calculates how much storm surge a hurricane will probably cause.

The Atlantic hurricane season is from June 1 to November 30, but most hurricanes occur during the fall months. The Eastern Pacific hurricane season is from May 15 to November 30. (Below is a graphic that shows you when hurricanes are most active across parts of the world.)
When does hurricane season start?

Who names hurricanes?
From 1950 to 1952, tropical cyclones of the North Atlantic Ocean were identified by the phonetic alphabet (Able-Baker-Charlie-etc.), but in 1953 the US Weather Bureau switched to women's names. The rest of the world eventually caught on, and naming rights now go by the World Meteorological Organization, which uses different sets of names depending on the part of the world the storm is in. Around the U.S., only women's names were used until 1979, when it was decided that they should alternate a list that included men's names too. There's 6 different name lists that alternate each year. If a hurricane does significant damage, its name is retired and replaced with another.
Atlantic Hurricane Names
Eastern Pacific Hurricane Names
Nothing except geography. Tropical storms occur in several of the world's oceans, and except for their names, they are essentially the same type of storm. In the Atlantic Ocean, Gulf of Mexico, and the Eastern Pacific Ocean, they are called hurricanes. In the Western Pacific Ocean, they are called typhoons. In the Indian Ocean, the Bay of Bengal, and Australia, these types of storms are called cyclones.
What is the difference between a hurricane and a typhoon?
(This is a satellite animation of Hurricane Georges, which struck the Mississippi Gulf coast in 1998.)

The brave "hurricane hunters" work for the National Oceanic and Atmospheric Administration (NOAA). Each mission lasts about ten hours, with the crews passing four to six times through the storm. The planes carry radar, sophisticated computers, and weather instruments that determine characteristics such as temperature, air pressure, wind speed, and wind direction inside the hurricane. The crews also release instruments that measure temperature, air pressure, and wind at different levels as the devices drop through the hurricane toward the ocean. By mission's end, NOAA can warn everyone in the hurricane's path. (Below is a satellite image of Hurricane Mitch back in October 1998. The Hurricane Hunters flew into the eye of Mitch just as this Category 5 hurricane with winds of 155 mph smacked right into Central America.)

Who are the "Hurricane Hunters"?
Coastal beach erosion is the wearing away of land, the removal of beach or dune sediments by wave action, tidal currents, wave currents, or drainage. Waves are generated by storms, wind, or hurricanes and can cause coastal erosion. This may take the form of long-term losses of sediment and rocks, or merely the temporary redistribution of coastal sediments.

What is coastal beach erosion?

Hurricanes...Past and Present
Tropical Tracks: Click to see the tracks of this year's storms.

Know the Lingo Past Hurricane Info: Click to find all the data and information about a specific hurricane by just knowing the year.
HURRICANE WATCH - Hurricane conditions with sustained winds of 74 mph or greater are possible in your area within the next 36 hours. This WATCH should trigger your family's disaster plan, and protective measures should be initiated. Especially, those actions that require extra time such as securing a boat and leaving a barrier island.
TROPICAL STORM WATCH - Tropical Storm conditions with sustained winds from 39 -74 mph are possible in your area within the next 36 hours.
HURRICANE WARNING - Hurricane conditions are expected in your area within 24 hours. Once this WARNING has been issued, your family should be in the process of completing protective actions and deciding the safest location to be during the storm.

COASTAL FLOOD WATCH - The possibility exists for the inundation of land areas along the coast within the next 12 to 36 hours.

COASTAL FLOOD WARNING - Land areas along the coast are expected to become, or have become, inundated by sea water above the typical tide action.

SMALL CRAFT ADVISORY - A small craft advisory is a type of warning issued by the National Weather Service, most frequently in coastal areas. It is issued when winds have reached, or are expected to reach within 12 hours, a speed marginally less than that which is considered gale force, usually 25-38 mph.

Click Here to see if there are any active warnings in your area.
Hurricane Stages
Saffir-Simpson Hurricane Scale

Category

Winds (MPH)

Pressure (Millibars)

Pressure (Inches)

Storm Surge
(Feet)

Damage

3

111-130

964-945

28.47-27.91

9'-12'

Extensive

Click Here to watch a variety of videos teaching you the ins and outs of nature's fury. I would like to give a special thanks to Pinellas County Emergency management for putting these instructional videos together.
Hurricane Safety Tips

BEFORE A HURRICANE: Have a disaster plan and a pet plan ready. Before a storm threatens, contact your veterinarian or local humane society for information on preparing your pets for an emergency. Board up windows and b ring in outdoor objects that could blow away. Make sure you know which county or parish you live in and k now where all the evacuation routes are.

Stay away from low-lying and flood prone areas. Always stay indoors during a hurricane, because strong winds will blow things around. Leave mobile homes and to go to a shelter. DURING A HURRICANE: If your home isn't on higher ground, go to a shelter. If emergency managers say to evacuate, then do so immediately.
AFTER A HURRICANE: Stay indoors until it is safe to come out. Check for injured or trapped people, without putting yourself in danger. Watch out for flooding which can happen after a hurricane. Do not attempt to drive in flooding water. Stay away from standing water. It may be electrically charged from underground or downed power lines. Don't drink tap water until officials say its safe to do so.

Evacuation Tips: Here is a list of tips on what you should do, if you chose to evacuate as a hurricane approaches.
Hurricane Activities
Hurricane Supply Checklist: Here is a list of what what you will need if you chose to stay at your home during a hurricane.
Lesson Plan: Here is a great lesson plan on learning about hurricane safety. In this activity, Owlie teaches kids about hurricanes and quizzes them about what they learned. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.
Lesson Plan: Here is a great lesson plan on understanding hurricanes. Students will learn how wind speed increases the height and why higher waves occur in shallower water. This activity is for grades 6-8.

Lesson Plan: Here is a great interactive lesson plan on allowing kids to create their very own hurricane. It lets you try to create ideal hurricane conditions by changing the winds, latitude, moisture, and sea temperature. It even keeps score! This is a great activity for 5-8th graders.Lesson Plan: Here is a great lesson plan on elementary reading comprehension. This lesson contains a broader vocabulary, more hurricane facts, and more thought-provoking writing prompts. It works well for grades 3-5. Note: This is a PDF file, so you need to have Adobe Acrobat Reader. Lesson Plan: Here is a great interactive lesson plan that lets kids aim a hurricane. It lets you move the hurricane symbol, high pressure symbol and low pressure symbol to track your very own hurricane. Sometimes your hurricane will make landfall, other times it misses the U.S. all together. It lets kid understand how important the setup of weather impacts where hurricanes go.

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!
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.
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.

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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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The wind at the beach is whipping at 95 miles an hour. Waves 16 feet tall are crashing down. Even sharks are heading out to calmer waters. A hurricane is on its way.

These powerful storms have different names depending on where in the world they form. They're called hurricanes if they occur in the Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and eastern Pacific Ocean. In the western Pacific Ocean, they're known as typhoons; in the southern Pacific and Indian Oceans, they're called cyclones.

Scientists know them all as tropical cyclones. As many as 150 occur around the world each year.

How a hurricane forms

Hurricanes are strong storms that start in the ocean and have winds of at least 74 miles an hour. In the Northern Hemisphere (the part of Earth north of the equator), hurricanes generally occur between mid-August to late October. In the Southern Hemisphere (the area south of the equator), storm season is between April and December, with peak storm activity around May and November. During these times, oceans have warmer water, which is what a hurricane needs to form.

Hurricanes begin when a tropical depression forms in the ocean. A tropical depression is a line of rain showers and weak thunderstorms that circle around an area of low air pressure. If the water is at least 79°F, a hurricane might form.

The low air pressure causes the hot, humid air from the ocean to rise in a spiral shape. As that warm air rises, it releases heat, cools down, and condenses into gusty bands of clouds and storms. The low-pressure area continues to suck up hot, moist air, and the spiral gets stronger and faster.

When winds reach 39 miles an hour, the tropical depression becomes a tropical storm. When winds reach 74 miles an hour, it's officially a hurricane.

As a hurricane moves over cooler water or hits land, it loses the warm water that fuels it and begins to weaken. But dangerous winds can still cause damage, and storm surges-when a strong storm pushes ocean water ashore-can flood coastal areas with more than 20 feet of water. Heavy rains and floods can continue far inland.

Understanding a hurricane's strength

Hurricanes are classified by wind speed and the amount of damage that scientists predict the storm will cause when it reaches land. (In the United States, this is done by the National Hurricane Center, part of the National Oceanic and Atmospheric Administration.)

For example, a Category 1 storm has wind speeds of 74 to 95 miles an hour and will probably damage some homes and cause a few power outages. But a Category 5 hurricane is considered a powerful, destructive storm. These storms have winds of 156 miles an hour or more and will likely cause so much damage that people must abandon their communities, which will need months to clean up.

These rankings can help predict the severity of an approaching storm, but any hurricane can be devastating. For instance, Hurricane Katrina was only a Category 3 storm when it hit the U.S. Gulf Coast around Louisiana and Mississippi in 2005. The storm caused over $100 billion in damages, and nearly 2,000 people died.

Predicting the path

Meteorologists can predict the path that a hurricane will travel-and where it will make landfall-by analyzing changes in temperature, cloud formations, and air circulation patterns. That data is gathered by specialized aircraft, satellites, and weather surveillance radar from above the Earth. Other scientific devices that float in the ocean can measure winds, waves, and air and sea temperatures.

The information from these tools is used to create computer forecasting models used by scientists to learn when a storm is forming, where it might travel, and how severe it will be. That can help local officials release warnings or even evacuation orders in order to keep people safe from the coming hurricane.

Naming hurricanes

Once a storm's wind speed reachers 39 miles an hour, it becomes a tropical storm and is given a name. The name is chosen from a list of about 20 names issued by the World Meteorological Organization at the beginning of the hurricane season. They alternate between female and male names.

But you won't see David, Katrina, Andrew, or Laura on that list-those hurricanes were so destructive that the names have been removed. And you won't hear of any hurricanes starting with Q, U, X, Y, or Z, since few names begin with those letters.

More powerful storms in the future?

In the future, scientists don't expect to see more hurricanes, but they do expect more powerful ones. That's because hurricanes get bigger more quickly in warmer water. As climate change causes ocean temperatures to rise, scientists predict that future hurricanes will be rainier and longer lasting.

How to survive a hurricane

The safest thing to do is to follow local instructions and leave the area, or evacuate, if officials say you should. Here are other tips for staying safe if a hurricane is headed your way.

Before a hurricane
* Know the evacuation routes in your neighborhood, and make sure your parents have put gas in the car.
* Check your yard to see if any branches are broken on trees and alert an adult if they are. (Those branches could break off and soar through a window!)
* Bring in anything that could blow away, like garbage cans and outdoor furniture.
* Close all your windows, storm shutters, blinds, and curtains.

During a hurricane
* If you haven't evacuated, stay indoors where it's safe.
* Fill all bathtubs and sinks with clean, cold water in case water lines are damaged or the supply becomes contaminated.
* Ride out the storm in an interior room, such as a hallway or closet on the lowest level of your house.
* Never go near a window, even if it's boarded up.
* If it looks like the storm is going to hit your home, lie on the floor under a table or another sturdy object.
* Limit the use of cell phones to free up space for emergency calls.

After a hurricane
* Listen to weather reports to make sure the storm has passed. A calm sky might be just the hurricane's eye, or center, and more storm fun will be on the way.
* If you evacuated, return only when officials say it's safe.
* Check all food for spoilage. Remember: If in doubt, throw it out.

Adapted from the Nat Geo Kids book Extreme Weather by Thomas Kostigen, revised for digital by Laura Goertzel

Learn more about hurricanes, typhoons, and cyclones at National Geographic.

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Learn what causes these deadly storms-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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Check out these epic tsunami facts from National Geographic Kids! How do tsunamis form? And how big are they? Find out all about them in our tsunami facts...

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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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Enjoy our awesome range of Earth facts for kids. Check out the cool trivia and have fun learning about some of our planet's most amazing features.

Tsunami Facts

Check out our tsunami facts for kids and learn some interesting information related to these great walls of water that can cause so much destruction. Find out what causes tsunamis and read about some notable recent examples of tsunamis that have occurred around the globe.

Tsunamis are huge waves of water that are usually caused by earthquakes or volcanic eruptions.

As a tsunami approaches the shore, water may recede from the coast, if it is shallow enough the water may be pulled back hundreds of metres. If you are in the area, observing this is a good indication that a tsunami is on the way.

Regions in tsunami danger zones often have warning systems in place to give people as much time to evacuate as possible.

When tsunamis hit shallow water (often near the coast) they slow down but increase in height.

An earthquake in the Indian Ocean off Indonesia in December 2004 caused a tsunami that killed over 200000 people in 14 countries. More earthquake facts.

In March 2011, the Tohoku earthquake off the eastern coast of Japan caused a tsunami that was a major factor in the death of over 15000 people.

The tsunami waves created by the Tohoku earthquake reached heights of over 40 metres (131 feet) in some areas, wiping out coastal towns and causing a number of nuclear accidents.

The Japanese word tsunami literally means 'harbor wave'.

Tsunamis are sometimes referred to as tidal waves but this term has fallen out of favour because tsunamis are not related to tides.

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Tsunami Facts for Kids - Interesting Information about Tsunamis

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Enjoy our awesome range of Earth facts for kids. Check out the cool trivia and have fun learning about some of our planet's most amazing features. Tsunami Facts Check out our tsunami facts for kids and learn some interesting information related to these great walls of water that can cause so much destruction.

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Tsunami | The Dr. Binocs Show | Educational Videos For Kids

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Explore National Geographic. A world leader in geography, cartography and exploration.

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What is a Tsunami? Facts & Information - Geography for Kids | Educational Videos by Mocomi

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How Tsunamis are Formed | Worksheet | Education.com

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Do you know how Tsunamis are formed? This worksheet shows the physics behind tsunami formation.

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What is a tsunami?
A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water. With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage!

How are tsunamis generated?
Tsunamis are generated by any large, impulsive displacement of the sea level. The most common cause of a tsunami is sea floor uplift associated with an earthquake. Tsunamis are also triggered by landslides into or under the water surface, and can be generated by volcanic activity and meteorite impacts.

How often do tsunamis occur?
On the average, two tsunamis occur per year throughout the world which inflict damage near the source. Approximately every 15 years a destructive, ocean-wide tsunami occurs.

Can strike-slip (horizontal motion) earthquakes trigger tsunamis?
Yes, approximately 10-15% of damaging tsunamis are triggered by strike-slip earthquakes. This type of earthquake is less likely to trigger a tsunami than one with vertical motion. The waves are likely generated by associated landslides or motion of a sloping bathymetric feature. Tsunamis generated by strike-slip earthquakes normally affect regions near the source only.

What does the word "tsunami" mean?
Tsunami (soo-NAH-mee) is a Japanese word meaning harbor wave.

How fast do tsunamis travel?
Tsunami velocity depends on the depth of water through which it travels. Velocity equals the square root of the product of the water depth times the acceleration of gravity. Tsunamis travel approximately 475 mph in 15,000 feet of water. In 100 feet of water the velocity drops to about 40 mph.

Did you know...A tsunami travels from the central Aleutian Islands to Hawaii in about 5 hours and to California in about 6 hours, or from the Portugal coast to North Carolina in about 8.5 hours.

How big is a tsunami?
Tsunamis range in size from inches to over a hundred feet. In deep water (greater than 600 feet), tsunamis are rarely over 3 feet and are not normally noticed by ships due to their long period or time between crests. As tsunamis propagate into shallow water, the wave height can increase by over 10 times. Tsunami heights vary greatly along a coast. The waves can be amplified by shoreline and sea floor features. A large tsunami can flood low-lying coastal land over a mile from the coast.

What does a tsunami look like when it reaches shore?
Normally, a tsunami appears as a rapidly advancing or receding tide. In some cases, a wall of water or series of breaking waves may form.

How is a tsunami different from a wind-generated wave?
Wind-generated waves usually have periods or time between crests between 5 and 15 seconds. Tsunami periods normally range from 5 to 60 minutes. Also, wind-generated waves break as they shoal and lose energy offshore. Tsunamis act more like a flooding wave. A twenty foot tsunami is a twenty foot rise in sea level.

What are nature's signs that a tsunami may be imminent?
There are a few signs like hard ground shaking for 20+ seconds near the coast or a sudden sea level withdrawal. Tsunamis may be accompanied by loud, booming noises.

Can earthquakes and tsunamis be predicted?
No, earthquakes cannot be predicted. Once an earthquake has occurred, the arrival time of a tsunami, if generated, can be determined accurately. There is not normally enough time to accurately predict tsunami heights near the source. Away from the source, tsunami wave heights can be estimated based on mathematical tsunami models and observed wave heights.

Aerial video of the tsunami that devastated Japan on March 11, 2011.

Click Here to see an animation of an earthquake and the resulting tsunami. It's great for kids, because they get to see how it actually happens!
What are some of the most damaging tsunamis?

Japan: Major tsunami in 2011 generated in the Pacific Ocean.

Asia: Asian tsunami in 2004 generated in the Indian Ocean.

Alaska: Major tsunamis were generated along the Alaskan coast in 1946, 1957, 1958, 1964, and 1965. Many other locally generated tsunamis occurred prior to those dates.

US/Canada West Coast: Tsunamis were generated locally in 1812, 1873, 1878, 1927, 1930, 1946 and 1949. The west coast was also impacted by tsunamis generated in other regions in 1877, 1946, 1952, 1957, 1960, 1964, 1975, 2006, and 2010.

US/Canada Atlantic Coast: Tsunamis were recorded in 1755, 1884, 1886, and 1929.

Puerto Rico and the Virgin Islands experienced damaging tsunamis in 1867 and 1918.

Click Here for the NOAA/National Geophysical Data Center tsunami catalog.

TSUNAMI WARNING- A tsunami warning indicates that a tsunami may be imminent and that coastal locations in the warned area should prepare for flooding. The initial warning is typically based solely on seismic information. After the tsunami is recorded on sea level gages, the warning will be cancelled, restricted, expanded, or downgraded to an advisory. Warnings indicate that flooding up to the maximum expected limit is possible and residents should follow their local emergency management instructions. Warnings are issued when the earthquake information or tsunami forecasts indicate that a wave over 1 meter in amplitude is expected, possible, or ongoing.

TSUNAMI ADVISORY- A tsunami advisory indicates a tsunami which may produce strong currents and is dangerous to those in or very near the water is expected. Large inundations are not expected in areas under advisory status. Advisories will be cancelled, extended, or upgraded to a warning depending on the event severity. Advisories are issued when the tsunami forecast is in the range of 0.3 to 1 meter, or an observed tsunami is in the range of 0.5 to 1.0 meters.

TSUNAMI WATCH- A tsunami watch is an early alert issued to areas which may later be impacted by a tsunami. Tsunami impact is normally at least three hours away for regions within a tsunami watch. The watch will either be upgraded to a warning or advisory in subsequent messages or cancelled depending on the severity of the tsunami. People within a watch area should stay alert for further information regarding tsunami threat.

CREST - The top of a wave.

FJORD - A narrow sea inlet between cliffs or steep slopes.

SURGE - A large wave or billow.

TROUGH - The lowest point between waves.

Click Here to get the latest tsunami warning information from the NWS.

PLAN FOR A TSUNAMI: Have a disaster plan. Know whether you're at risk for danger. Plan an evacuation route. 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.

DURING A TSUNAMI: Follow the instructions issued by local authorities. You will probably want to evacuate immediately. Get to higher ground and as far inland as you can.

AFTER A TSUNAMI: Help injured or trapped people. Stay out of a building if water remains around it. Tsunami waters can cause buildings to sink, floors to crack, or walls to collapse. When re-entering homes, use extreme caution. Check for gas leaks. Open windows and doors to help dry things out. Look for fire hazards.

Lesson Plan: Here is a great lesson plan on learning about tsunamis. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.

Lesson Plan: Here is a great lesson plan on tracking a tsunami.

Lesson Plan: Here is a great lesson plan on tsunamis and how they devastating effects they may cause in the world.

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What is a tsunami? A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water.

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What is an Earthquake? Facts & Information - Geography for Kids | Educational Videos by Mocomi

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What Is An Earthquake? | The Dr. Binocs Show | Educational Videos For Kids

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Tea Time with Tayla - Kid Songs, Nursery Rhymes and Educational Videos for Children

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Earthquake Safety for Kids on Tea Time with Tayla

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Explore National Geographic. A world leader in geography, cartography and exploration.

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Kid's learn about the science of earthquakes. What causes them and where they happen.

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Explore National Geographic. A world leader in geography, cartography and exploration.

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Introduction to Earthquakes & Tsunamis

Turn on the TV or read the newspapers and almost always there is something devastating happening somewhere as a result of sheer nature's power. Examples of such natural occurrences are hurricanes, tornados, wildfires, volcanic eruptions, flooding, earthquakes and tsunamis. These are usually not caused directly by humans, but their effects live with us for a long time. In this lesson we shall look at one of such natural occurrences...earthquakes!

Simply, earthquakes are the rumblings, shaking or rolling of the earth's surface. It is usually what happens when two blocks of the earth suddenly slip past one another, or break apart from each other as a result of tension caused by prolonged energy build up. Earthquakes come in many forms. It can be felt as a shock under your feet, or may be very powerful and destructive enough to flatten an entire city. They can happen anywhere, land or sea.

What is an Earthquake?

Foreshocks, Mainshocks and Aftershocks:
Sometimes, there are smaller shocks that occur before (foreshock) and after (aftershock) a main earthquake (mainshock). Sometimes foreshocks are so big and scientists are unsure if it is the main shock. Foreshocks and aftershocks can occur for days, weeks and months of a main earthquake.

Earthquakes are also called temblors.

It is important to understand
the earth's makeup to help understand earthquakes better.

In this diagram, you will notice that the inner and outer core of the earth (middle part) are liquid in nature, containing iron and nickel of extreme temperatures (5,500°C).

The Mantle is semi-molten rock, also called magma. The outer is the crust, which is the hard part of the earth that forms the surface. This outer crust includes the land on which we live, the oceans and ocean deeps and anything within 40km (approx) down the earth's surface.

Earthquakes are developed in the outer crust of the earth.

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Introduction to Earthquakes & Tsunamis Turn on the TV or read the newspapers and almost always there is something devastating happening somewhere as a result of sheer nature's power. Examples of such natural occurrences are hurricanes, tornados, wildfires, volcanic eruptions, flooding, earthquakes and tsunamis.

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The ground shakes, buildings tumble and the earth heaves and cracks. Serious earthquakes are terrifying and dangerous, but are rare in the U.S. But why do earthquakes happen? The earth is made up of four layers - the inner core, outer core, mantle and crust. The mantle and crust are a thin skin compared to the other layers.

The mantle is about 1,750 miles thick, while the crust is only about 8 miles thick. This thin skin is broken into pieces called tectonic plates. The plates are like puzzle pieces, floating on top of the Earth's inner core. Sometimes the pieces slide under or against each other and become stuck.

When the pieces slide apart, they create tremendous force. This force causes the earth to shake and ripple. Over 80 percent of the earth's earthquakes happen in the Pacific Ocean, in a place known as the "Ring of Fire." Annually, around 10,000 people die in earthquakes every year. Most of the deaths happen when people are trapped in falling buildings. After an earthquake, mudslides, fires and tsunamis can also hurt people.

Fun Facts All About Earthquakes for Kids

Alaska, California and Hawaii have the most earthquakes in the U.S. Other western states, like Nevada, Idaho, Washington and Oregon are prone to earthquakes or can be damaged by earthquakes that happen in Alaska and California.

Alaska has more earthquakes than any other U.S. state. It has experienced over 12,000 earthquakes in the last 30 years. Alaska is followed by California, Hawaii, Nevada, Washington, Idaho, Wyoming, Montana and Utah.

Underneath the Earth's surface lie tectonic plates. These plates move and shift over time. Sometimes they slide under one another or push up against each other, creating enormous stress. When they move again, they cause an earthquake.

Scientists who study earthquakes are called seismologists.

Seismologists can tell how serious an earthquake is by a machine called a seismogram, which rates the intensity of the quake's shaking.

Scientists can use special instruments to record an earthquake's strength. An earthquake rated 3 to 5 is minor; an earthquake rated 5 to 7 is moderate to strong; an earthquake rated 7 to 8 is major; an earthquake rated 8 or above is great.

On average, one earthquake measuring 8 or above happens every year.

The area near Japan in the Pacific Ocean has the most earthquakes in the world. This area also has a lot of volcanoes. It is called the Ring of Fire.

Most people who die in earthquakes die when buildings collapse on them. Others die in floods, fires or mudslides that happen after the earthquake.

May 22nd 1960 in Valdivia Chile the largest ever recorded Earthquake measuring a whopping 9.5 magnitude struck.

December 26th 2004 an Earthquake in the Indian Ocean measuring a magnitude of 9.1 on the Richter Scale resulted in a massive Tsunami hitting the region which resulted in the deaths of over 230,000 people.

March 11th 2011 off the coast of Honshu Japan a magnitude 9.0 earthquake caused a massive Tsunami to hit the coast. The Tsunami caused over 18,000.

On our planet earth we have four different types of dip-slip-faults and they are Normal - Reverse - Thrust - Strike Up.

Earthquake Vocabulary

Learn More All About Earthquakes and Why They Happen

Imagine that you're sitting in school when the ground begins to shake. Books fall off the shelves and you might even be thrown from your chair. That's what happens when an earthquake occurs. Earthquakes are the most deadly of all natural disasters. Over 10,000 people die every year in earthquakes.

Easy Science All About Earthquakes for Kids Video

Watch this interesting video all about earthquakes:

Earthquake Q&A

Question: Do all earthquakes cause damage?

Answer: Most earthquakes cause only minor shaking. Southern California has about 10,000 earthquakes every year. Some of them are so mild people don't even feel them.

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Question: What can I do to be safe in an earthquake?

Answer: If you're in a building in an earthquake, get under a table or desk and hold onto it. If you're outside, move to an open area away from trees, buildings or power lines.

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Question: What should I do to keep safe in an earthquake?

Answer: The best way to survive an earthquake is to take cover under a sturdy table. Get down low and place your hands over your head. You can even duck down in a door frame or curl up next to a couch or bed. Don't go outside, though. Many people die from falling debris.

Enjoyed the Natural Science for Kids website all about Earthquakes info? Take the FREE & fun all about Earthquakes quiz and download FREE all about Earthquakes worksheet for kids. For lengthy info click here.

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All About Earthquakes and Why They Happen Fun Science Facts for Kids. Learn more all about Earthquakes through our Easy Earth Science for Kids website.

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The amount of water it takes to cause a flood depends on how much water a river, stream, or other receptacle (container) can hold. Example: If you were to put the plug in your bathtub, turn the water on and leave the room, when the tub was filled, it would spill over and flood the bathroom.

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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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FLOODS - The Dr. Binocs Show | Best Learning Videos For Kids | Peekaboo Kidz

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Facts about floods

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Lesson description: Weather Wiz Kids is a fun and safe website for kids about all the weather info they ... Flash floods are the #1 weather-related killer in the U.S. Nearly 80% of flash ...

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Be Prepared

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Lesson description: Weather Wiz Kids is a fun and safe website for kids about all the weather info they ... Flash floods are the #1 weather-related killer in the U.S. Nearly 80% of flash ...

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Causes and Impacts

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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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Rain & Floods

How does rain form?
Water droplets form from warm air. As the warm air rises in the sky it cools. Water vapor (invisible water in the air) always exists in our air. Warm air holds quite a bit of water. For example, in the summer it is usually very humid. When enough of these droplets collect together, we see them as clouds. If the clouds are big enough and have enough water droplets, the droplets bang together and form even bigger drops. When the drops get heavy, they fall because of gravity, and you see and feel rain.

What causes rain?

When clouds develop or rain occurs, something is making the air rise. Several things can make this happen. Mountains, low-pressure areas, cold fronts, and even the jet stream.

How big are raindrops?
Raindrops are much smaller than we think! They are actually smaller than a centimeter. Raindrops range from 1/100 inch (.0254 centimeter) to 1/4 inch (.635 centimeter) in diameter.

How fast do raindrops fall?
Not including wind-driven rain, raindrops fall between 7 and 18 miles per hour (3 and 8 meters per second) in still air. The range in speed depends on the the size of the raindrop. Air friction breaks up raindrops when they exceed 18 miles per hour.

What is a flood?
A flood results from days of heavy rain and/or melting snows, when rivers rise and go over their banks.

What is a flash flood?
A flash flood is sudden flooding that occurs when floodwaters rise rapidly with no warning within several hours of an intense rain. They often occur after intense rainfall from slow moving thunderstorms. In narrow canyons and valleys, floodwaters flow faster than on flatter ground and can be quite destructive.

Do flash floods hurt people?
Flash floods are the #1 weather-related killer in the U.S. Nearly 80% of flash flood deaths are auto related. Know beforehand if your area is a flood risk.

How much water is needed for your car to float away?
A mere 2 feet of water can float a large vehicle or even a bus. This is why you should never drive through flooded roads. Just 6 inches of rapidly moving flood water can knock a person down.

What is a monsoon?
A monsoon is a seasonal wind, found especially in Asia that reverses direction between summer and winter and often brings heavy rains. In the summer, a high pressure area lies over the Indian Ocean while a low exists over the Asian continent. The air masses move from the high pressure over the ocean to the low over the continent, bringing moisture-laden air to south Asia. During winter, the process is reversed and a low sits over the Indian Ocean while a high lies over the Tibetan plateau so air flows down the Himalaya and south to the ocean. The migration of trade winds and westerlies also contributes to the monsoons. Smaller monsoons take place in equatorial Africa, northern Australia, and, to a lesser extent, in the southwestern United States.

What is radar?
Radar is an electronic instrument, which determines the direction and distance of objects that reflect radio energy back to the radar site. It stands for Radio Detection and Ranging. This is what meteorologists use to see rain or snow.

What is Doppler Radar? Doppler Radar detects precipitation intensity, wind direction and speed, and provides estimates of hail size and rainfall amounts. Doppler Radar gives forecasters the capability of providing early detection of severe thunderstorms that may bring strong damaging winds, large hail, heavy rain, and possibly tornadoes. Combined with satellites, radar gives forecasters the ultimate tools to provide accurate forecasts and advanced severe weather warnings.

Doppler Radar gets its name from the Doppler Effect. Have you ever listened to a train whistle as it was coming toward you? You probably noticed that the pitch of the whistle changed as the train passed you and moved away. This change in the frequency of sound is called the Doppler Effect. Doppler Radar measures the changes in the frequency of the signal it receives to determine the wind. How does Doppler Radar work?

The National Weather Service has installed a new type of Doppler Radar called NEXRAD Radar. NEXRAD stands for Next Generation Radar. This radar produces many different views of storms and rain that allows meteorologists to determine if a storm could be severe.
What is NEXRAD Radar?

Know the Lingo

FLOOD WATCH - means that an overflow of water from a river is possible for your area.

FLASH FLOOD WATCH - means that flash flooding is possible in or close to the watch area. Flash Flood Watches can be put into effect for as long as 12 hours, while heavy rains move into and across the area.

FLOOD WARNING - means flooding conditions are actually occurring in the warning area.

FLASH FLOOD WARNING - means that flash flooding is actually occurring in the warning area. A warning can also be issued as a result of torrential rains, a dam failure or snow thaw.
Click Here to see if there are any active warnings in your area.
Flood Safety Tips

BEFORE A FLOOD: Have a disaster plan and prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food, can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water.
DURING A FLOOD: Move to a safe area quickly. Move to higher ground, like the highest floor of your home. Avoid areas subject to sudden flooding like low spots and canyons. Avoid already flooded areas. If a flowing stream of water is above your ankles stop, turn around and go the other way. Do not attempt to drive through a flooded road. The depth of the water is not obvious and the road may be washed away. If your car stalls, leave it and seek higher ground. Rapidly rising water may engulf the car, pick it up and sweep it away. Kids should never play around high water, storm drains or viaducts. Be cautious at night, because its harder to see flood dangers. If told to evacuate, do so immediately.
AFTER THE FLOOD: Always, boil drinking water. Electrical equipment should be checked and dried before used.
Rain Activities

Lesson Plan: Here is a great lesson plan on learning about precipitation. In this activity, kids will use a weather map to answer questions about precipitation falling across the country. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.

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!

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.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.

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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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Explore drought information by state. See what types of plans states have implemented. Find contact information of drought planners in your state.

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Note: A new version of the program has been tested and released as of 12/7/2018. All of the necessary files are included in the download zip file.

Overview

The SPI Generator application serves to generate SPI (Standard Precipitation Index) data and illustrate how to interact with the SPI DLL (Dynamically Linked Library). The application reads in precipitation data and supports different time scales and data types (weekly, monthly). It outputs SPI data and, optionally, frequency and drought period data. In addition to executing as a Windows GUI (Graphical User Interface) it can also execute from the command line.

Standard Precipitation Index Summary

The SPI is calculated from the historical precipitation record at a weather station, where precipitation accumulation over a period of time is compared to that same period of time throughout the historical record at that location. The SPI for any precipitation accumulation value represents the probability that the location would have received at least the observed amount of precipitation over the time period. The SPI calculated in this program is based on representing the historical precipitation record with a gamma distribution. Positive SPI values represent wet conditions; the higher the SPI, the more unusually wet a period of time is. Negative SPI values represent dry conditions; the lower the SPI, the more unusually dry a period of time is.

The primary strength of the SPI is that its data can be compared between different climate regions. Since the SPI compares precipitation amounts at a weather station to that particular station's own precipitation history, SPI data from different stations usually can be directly compared, because the SPI communicates how anomalous a precipitation amount is, not just the raw departure from normal precipitation. For regions with highly seasonal precipitation (particularly where very little to no precipitation usually falls for several months), users should be cautious when directly comparing data from these areas. The SPI generator can also be used to compute standardized indices for other variables (commonly, streamflow). Some caution should be exercised when analyzing this output, since the gamma distribution may not be the best distribution to use to model non-precipitation variables.

Technical Details

The application requires Microsoft's .NET 4.0 framework and can be compiled as a 32- or 64-bit executable. The application consists of two files: a vb.net 4.0 application and a c#.net 4.0 DLL.

SPIGenerator.exe - the Windows console application.

StandardPrecipitationIndex.dll - the SPI DLL.

Running the application as a Windows application or command line produces the same program flow:

1. Retrieve and verify input parameters

2. Parse input file

3. Aggregate data

4. Calculate SPI

5. Write results to file

Note: More extensive documentation is available in the zip file.

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Note: A new version of the program has been tested and released as of 12/7/2018. All of the necessary files are included in the download zip file. The SPI Generator application serves to generate SPI (Standard Precipitation Index) data and illustrate how to interact with the SPI DLL (Dynamically Linked Library).

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During the 1930s, many measures were undertaken to relieve the direct impacts of droughts and to reduce the region's vulnerability to the dry conditions. Many of these measures were initiated by the federal government, a relatively new practice. Before the 1930s drought, federal aid had generally been withheld in emergency situations in favor of individual and self-reliant approaches. This began to change with the development of the Great Depression in the late 1920s and the 1933 inauguration of President Franklin Delano Roosevelt. The depression helped "soften deep-rooted, hard-line attitudes of free enterprise, individualism, and the passive role of the government", thus paving the way for Roosevelt's New Deal programs, which in turn provided a framework for drought relief programs for the Great Plains (Warrick, 1980).

Warrick et al. (1975) describe these drought relief programs, which are credited with saving many livelihoods throughout the drought periods. The programs had a variety of goals, all of which were aimed at the reduction of drought impacts and vulnerability:

Providing emergency supplies, cash, and livestock feed and transport to maintain the basic functioning of livelihoods and farms/ranches.

Establishing health care facilities and supplies to meet emergency medical needs.

Establishing government-based markets for farm goods, higher tariffs, and loan funds for farm market maintenance and business rehabilitation.

Providing the supplies, technology, and technical advice necessary to research, implement, and promote appropriate land management strategies.

Removing dead trees and planting new trees to alleviate psychological stress and create shelter belts.

President Roosevelt visiting a farmer who received a drought relief grant, Mandan, North Dakota, 1936. Photo by Arthur Rothstein.(Image: Library of Congress, Prints & Photographs Division, FSA-OWI Collection, LC-DIG-fsa8b28231 DLC)

As important as these programs may have been, the survival of a majority of the families and enterprises undoubtedly rested solely with their perseverance and integrity. Whether they stayed or moved into the drought regions or migrated to other areas in hopes of a better life, families encountered new hardships and obstacles that would require ingenuity, resilience, and humility.

Those who remained in the drought regions were forced to endure severe dust storms and their health effects, diminished incomes, animal infestations, and the physical and emotional stress over their uncertain futures. Humor helped; tales about birds flying backward to keep from getting sand in their eyes, housewives scouring pots and pans by holding them up to keyholes for a sandblasting, and children who had never seen rain were among the favorite stories of Dust Bowl inhabitants. In the end, it was a combination of willpower, stamina, humor, pride, and, above all, optimism that enabled many to survive the Dust Bowl. These qualities are succinctly expressed in the comments of one contemporary Kansan: "We have faith in the future. We are here to stay" (quoted in Hurt, 1981).

The 1930s drought and its associated impacts finally began to abate during spring 1938. By 1941, most areas of the country were receiving near-normal rainfalls. These rains, along with the outbreak of World War II, alleviated many of the domestic economic problems associated with the 1930s. In fact, the new production demands and positive climatic conditions brought the United States into a rapid economic boom.

Even though short-term conditions seemed to be relatively stable, this production growth had some drawbacks. One drawback (described by Hurt, 1981) was that the start of World War II shifted remaining funds and priorities away from drought-related programs. Men were taken off work programs to enter the armed forces and to produce for the war effort. Moreover, items such as gasoline and replacement parts were redirected from federal drought and conservation programs to the war efforts. This meant that conservation programs and research were significantly reduced during this period. Another drawback was that with the return of the rains, many people soon forgot about conservation programs and measures implemented during the 1930s droughts. This led to a return to some of the inappropriate farming and grazing practices that made many regions so vulnerable to drought in the 1930s.

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The Dust Bowl | National Drought Mitigation Center

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During the 1930s, many measures were undertaken to relieve the direct impacts of droughts and to reduce the region's vulnerability to the dry conditions. Many of these measures were initiated by the federal government, a relatively new practice. Before the 1930s drought, federal aid had generally been withheld in emergency situations in favor of individual and self-reliant approaches.

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What is the difference between dry weather and a drought? Who decides? How do the effects of drought differ from region to region? What are the initial steps to begin a drought planning process? Learn how to use the U.S. Drought Monitor to understand drought severity.

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There are four different kinds of drought: permanent, seasonal, unpredictable, and invisible.

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What is a drought?
A drought is when there is a lack of precipitation over an extended period of time, usually a season or more, resulting in a water shortage for some activity, group, or environmental sector. Its impacts result from the interplay between the natural event (less precipitation than expected) and the demand people place on water supply, and human activities can exacerbate the impacts of drought.

What causes a drought?
Drought has many causes. It can be caused by not receiving rain or snow over a period of time. If you live in a place where most of the water you use comes from a river, a drought in your area can be caused by places upstream from you not receiving enough moisture. There would be less water in the river for you and other people who live along the river to use. People can also play a big role in drought. If we use too much water during times of normal rainfall, we might not have enough water when a drought happens.

Can scientists predict if a drought is going to happen?
No! Studies conducted over the past century have shown that meteorological drought is never the result of a single cause. It is the result of many causes including, global weather patterns, high pressure, the tropical outlook and other global-scale variables.

Are there places in the United States that experience drought?
Yes! The Western United States is experiencing an exceptional and extreme drought at this time. To see the map, Click Here to see the current U.S. Drought Monitor.

What was the Dust Bowl?
Of all the droughts that have occurred in the United States, the drought events of the 1930s are widely considered to be the "drought of record" for the nation. The 1930s drought is often referred to as if it were one episode, but it was actually several distinct events occurring in such rapid succession that affected regions were not able to recover adequately before another drought began. The term Dust Bowl was coined in 1935 to describe the drought-affected south central United States in the aftermath of horrific dust storms. Although it technically refers to the western third of Kansas, southeastern Colorado, the Oklahoma Panhandle, the northern two-thirds of the Texas Panhandle, and northeastern New Mexico, the Dust Bowl has come to symbolize the hardships of the entire nation during the 1930s.

How bad was the drought in the Dust Bowl years?
In the 1930s, drought covered virtually the entire Plains for almost a decade. The drought's direct effect is most often remembered as agricultural. Many crops were damaged by deficient rainfall, high temperatures, and high winds, as well as insect infestations and dust storms that accompanied these conditions. The resulting agricultural depression contributed to the Great Depression's bank closures, business losses, increased unemployment, and other physical and emotional hardships. Although records focus on other problems, the lack of precipitation would also have affected wildlife and plant life, and would have created water shortages for domestic needs.

What was the Black Sunday Dust Storm?
The 1930s were times of tremendous hardship on the Great Plains. Settlers dealt not only with the Great Depression, but also with years of drought that plunged an already-suffering society into an onslaught of relentless dust storms for days and months on end. They were known as dirt storms, sand storms, black blizzards, and "dusters." It seemed as if it could get no worse, but on Sunday, the 14th of April 1935, it got worse. The day is known in history as "Black Sunday," when a mountain of blackness swept across the High Plains and instantly turned a warm, sunny afternoon into a horrible blackness that was darker than the darkest night. Famous songs were written about it, and on the following day, the world would hear the region referred to for the first time as "The Dust Bowl."

How does a drought affect our lives?
Drought affects our lives in many different ways because water is such an important part of so many of our activities. We need water to live, and animals and plants do too. We need water to grow the food we eat. We also use water for many different things in our lives, like washing dishes, cooking, bathing, and swimming or river rafting. Water is also used to help make the electricity we use to run the lights in our houses and the video games you may like to play. When we don't have enough water for these activities because of a drought, many people and many different things will be affected in many different ways.

How can we help if we're in a drought?
One of the easiest steps we can take to help mitigate the impacts of drought is conserving water. If we use water wisely at all times, more water will be available to us and to plants and wildlife when a drought happens. We can lose a lot of water doing simple everyday tasks. Did you know that turning off the water while you brush your teeth can save more than 100 gallons of water a month? If you have a leaky faucet, the drips can add up to 300 gallons of wasted water a month.

What are the different types of drought?
There are four basic approaches to measuring drought: meteorological, hydrological, agricultural, and socioeconomic. The first three approaches deal with ways to measure drought as a physical phenomenon. The last deals with drought in terms of supply and demand, tracking the effects of water shortfall as it ripples through socioeconomic systems.

Meteorological drought is defined usually on the basis of the degree of dryness (in comparison to some "normal" or average amount) and the duration of the dry period. Definitions of meteorological drought must be considered as region specific since the atmospheric conditions that result in deficiencies of precipitation are highly variable from region to region. For example, some definitions of meteorological drought identify periods of drought on the basis of the number of days with precipitation less than some specified threshold. This measure is only appropriate for regions characterized by a year-round precipitation regime such as a tropical rainforest, humid subtropical climate, or humid mid-latitude climate.

Agricultural drought links various characteristics of meteorological (or hydrological) drought to agricultural impacts, focusing on precipitation shortages, differences between actual and potential evapotranspiration, soil water deficits, reduced groundwater or reservoir levels, and so forth. Plant water demand depends on prevailing weather conditions, biological characteristics of the specific plant, its stage of growth, and the physical and biological properties of the soil. A good definition of agricultural drought should be able to account for the variable susceptibility of crops during different stages of crop development, from emergence to maturity.

Hydrological drought is associated with the effects of periods of precipitation (including snowfall) shortfalls on surface or subsurface water supply (i.e., streamflow, reservoir and lake levels, groundwater). The frequency and severity of hydrological drought is often defined on a watershed or river basin scale. Although all droughts originate with a deficiency of precipitation, hydrologists are more concerned with how this deficiency plays out through the hydrologic system. Hydrological droughts are usually out of phase with or lag the occurrence of meteorological and agricultural droughts. It takes longer for precipitation deficiencies to show up in components of the hydrological system such as soil moisture, streamflow, and groundwater and reservoir levels. As a result, these impacts are out of phase with impacts in other economic sectors.

Socioeconomic definitions of drought associate the supply and demand of some economic good with elements of meteorological, hydrological, and agricultural drought. It differs from the aforementioned types of drought because its occurrence depends on the time and space processes of supply and demand to identify or classify droughts. The supply of many economic goods, such as water, forage, food grains, fish, and hydroelectric power, depends on weather. Because of the natural variability of climate, water supply is ample in some years but unable to meet human and environmental needs in other years. Socioeconomic drought occurs when the demand for an economic good exceeds supply as a result of a weather-related shortfall in water supply.

Aquifer - an area that contains large amounts of water under the surface of the earth.

Climate - day-to-day weather over a longer period of time. Climatology is the study of climate.

Climograph - a graph that shows monthly average temperature and precipitation for some location.

Dam - a structure built across a river to hold back water for a variety of reasons, including protecting areas from floods, storing water, and generating power.

Desalination - the process of removing salts and other minerals from seawater so that it can be used for drinking water.

Drought - less rainfall than is expected over an extended period of time, usually several months or longer. Or, more formally, it is a deficiency of rainfall over a period of time, resulting in a water shortage for some activity, group, or environmental sector.

Drought Index - a numerical scale that scientists use to describe the severity of a drought. Scientists take many kinds of data (like streamflow, rainfall, temperature, and snowpack) and "blend" it into a single number, called a drought index value, to make it easier to understand the drought conditions of a particular area. Drought indices are one type of drought indicator.

Drought I ndicator - a way to look at one or more variables, such as precipitation, to describe available water in soil or hydrologic systems. It may be a record of a single measurement, such as rainfall at a particular rain gauge. It may also be a complex index. Drought indices (indexes) are a subset of drought indicators.

Dust Bowl - an area of the U.S. Plains that included parts of Kansas, Colorado, Oklahoma, Texas, and New Mexico. The term was coined in the 1930s, when dry weather and high winds caused many dust storms throughout the United States, but particularly in this area.

Erosion - a process that wears the earth's surface away, causing soil to move from one place to another. It's a natural process, but human activities can make it worse.

Groundwater - water that is found underground in spaces in soil, sand, or rocks.

Hydroelectricity - electricity created by channeling water through turbines in power stations located below dams.

Irrigation - an agricultural practice that involves providing water to crops through pipes, ditches, or streams.

Mitigation - actions that we can take before, or at the beginning of, drought to help reduce the impacts of drought. Mitigation includes actions as diverse as drought planning, implementing land use practices that increase the organic content and water-holding capacity of soil, and designing agricultural policy that doesn't encourage short-term economic gains at the expense of long-term productive capacity. The Intergovernmental Panel on Climate Change uses mitigation to mean reducing emissions of greenhouse gasses.

Reservoirs - water that's collected and stored in natural or manmade lakes.

Submarginal Farmland - lands with nutrient-poor soils and/or soils that have been damaged by poor cultivation practices.

Water Banking - a water management strategy that temporarily transfers water from those who are willing to lease it to those who are willing to pay to use it.

Water Recycling - reusing treated wastewater for purposes like agricultural and landscape irrigation. It's also referred to as water reclamation or water reuse.

Xeriscaping - a type of landscaping around homes and businesses that uses a limited amount of water.

Click on the chart to make larger!

Click Here to see the current U.S. Drought Monitor!

Lesson Plan: Here is a lesson plan on water conservation.

Lesson Plan: Here is a lesson plan on how drought affect agriculture.

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 drought? A drought is when there is a lack of precipitation over an extended period of time, usually a season or more, resulting in a water shortage for some activity, group, or environmental sector.

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Explore National Geographic. A world leader in geography, cartography and exploration.

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Drought in California

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Drought - The Dr. Binocs Show | Best Learning Videos For Kids | Peekaboo Kidz