October 31, 2014 06:02 UTC

Science & Technology

Severe Ocean Storms: The Science of Nature's Power

Read, listen and learn English with this story. Double-click on any word to find the definition in the Merriam-Webster Learner's Dictionary.

A Mississippi man lifts his left leg to remove water from his boot after wading through Isaac's flood waters A Mississippi man lifts his left leg to remove water from his boot after wading through Isaac's flood waters
x
A Mississippi man lifts his left leg to remove water from his boot after wading through Isaac's flood waters
A Mississippi man lifts his left leg to remove water from his boot after wading through Isaac's flood waters

Multimedia

Play or download an MP3 of this story
This is SCIENCE IN THE NEWS, in VOA Special English. I’m Barbara Klein.

And I’m June Simms. Today we tell about the science of severe ocean storms. Severe storms that develop over the Indian Ocean are called cyclones. Storms that form over the northwestern Pacific Ocean are typhoons. And storms that form over the eastern Pacific and the Atlantic Ocean are hurricanes. 

A storm named Isaac recently brought death and destruction to the United States and islands in the Atlantic and Caribbean Sea. Wide, slow-moving Isaac came to life over waters near the island of Puerto Rico. At the time, the storm was not yet a hurricane. Instead, it was called a tropical depression. Then it grew in strength and size, was declared a tropical storm, and stayed that way for days. 

Isaac passed over Haiti, killing at least twenty-nine people. Five people were confirmed dead from the storm in the Dominican Republic.

Weather experts finally declared Isaac a hurricane as it moved toward the southern United States. Parts of Louisiana were still recovering from Hurricane Katrina, a powerful storm seven years earlier.

Isaac’s strong winds and rains cut electricity to nine hundred thousand homes and businesses in the state. Damage to agriculture was estimated in the millions of dollars. The storm also struck hard in Mississippi, Arkansas and other states.

The city of New Orleans largely escaped severe damage. But areas near it, like Plaquemines Parish, suffered huge floods. Plaquemines is on a piece of land shaped like a finger. It runs along the Mississippi River into the Gulf of Mexico. That is where Isaac – and Katrina before it -- made landfall. Plaquemines also suffered major damage during Katrina.

Isaac caused a number of tornadoes, powerful wind storms, in states as far away as Illinois and Missouri. By the time it was over, nine people were reported dead in the United States. 

How did Isaac get its name? Naming storms and other natural events has been a tradition for centuries. For example, the name “Thor” was given to the mythical Norse god of thunder, the loud sound that follows lightning in the sky. 

An Australian scientist began calling storms by women's names before the end of the nineteenth century. During World War Two, scientists called storms by the names of their wives or girlfriends.

American weather experts started to use women's names for storms in nineteen fifty-three. In nineteen seventy-nine, they began to use men's names, too.

Scientists choose the names of storms many years before they are used. They decide on them at meetings of the World Meteorological Organization. The National Hurricane Center in Miami, Florida has one list for each of six years for Atlantic storms. Its experts name storms when they reach wind speeds of sixty-two kilometers an hour. That is true even if they never grow stronger.

The first name used in a storm season begins with the letter A. The second begins with B and so on. The letters Q, V, X, Y and Z are never used. And the same list of names is not used again for at least six years. And different lists are used for different parts of the world. A name is retired when the storm with this name has been very destructive, like Hurricane Katrina in two thousand five.

That same year, Greek letters had to be used for the first time to name storms in the Atlantic. That was the plan -- to call storms Alpha, Beta and so on -- if there were ever more than twenty-one named storms in a season. As it happened, there were twenty-eight.

Ocean storms develop when the air temperature in one area is different from the temperature nearby. Warmer air rises, while cooler air falls. These movements create a difference in atmospheric pressure. 

If the pressure changes over a large area, winds start to blow in a huge circle. High-pressure air is pulled toward a low-pressure center. Thick clouds form and heavy rains fall as the storm gains speed and moves over the ocean. Storms can get stronger as they move over warm ocean waters.

The strongest, fastest winds of a hurricane blow in the area known as the eyewall. It surrounds the center, or eye, of the storm. The eye itself is calm by comparison. 

Wind speeds in the most severe ocean storms can reach more than two hundred fifty kilometers an hour. Up to fifty centimeters of rain can fall. Some storms have produced more than one hundred fifty centimeters of rain.

These storms also cause high waves and ocean surges. A surge is a continuous movement of water that may reach as high as six meters or more. The water strikes low coastal areas. Surges are commonly responsible for about ninety percent of all deaths from ocean storms.

The National Hurricane Center in Miami keeps close watch on severe storms. It works with government officials and with radio and television stations to keep people informed. Experts believe this early warning system has helped reduce deaths from ocean storms in recent years. 

But sometimes people cannot or will not flee the path of a storm. That is what happened in some parts of Louisiana when Hurricane Isaac struck.

Studies have found that some people do not leave a storm-threatened area because they have no transportation or money for transportation. Another reason is that they fear their property will be damaged by other people, if not by the storm. Yet another reason is that people do not want to leave their farm animals or pets. Today, more plans exist for animal care during severe storms than in years before. 

Weather experts use computer programs to create models that show where a storm might go. The programs combine information such as temperatures, wind speed, atmospheric pressure and the amount of water in the atmosphere.

Scientists collect the information with satellites, weather balloons and devices floating in the oceans. They also receive information from ships and passenger airplanes and other flights. Government scientists use specially-equipped planes to fly into and around storms. The crews drop instruments tied to parachutes. The instruments collect information about temperature, pressure and wind speed.

Scientists use the Saffir-Simpson Hurricane Scale to measure the intensity of storms based on wind speed. This provides an idea of the amount of coastal flooding and property damage that might be expected. The scale is divided into five groups or categories.

The mildest hurricane is a category one, which is what Isaac was at its strongest. A hurricane called “Cat One” has winds of about one hundred twenty to one hundred fifty kilometers an hour. This storm can damage trees and lightweight structures. It can also cause flooding.

Wind speeds in a category two hurricane can reach close to one hundred eighty kilometers an hour. These storms are often powerful enough to break windows or blow the tops off houses.

Winds between about one hundred eighty and two hundred fifty kilometers an hour represent categories three and four. A more powerful storm is a category five hurricane.  Researchers say forces other than wind speed help cause extensive destruction. And the lower the air pressure, the stronger the storm. Water caused Hurricane Isaac’s worst damage. Flooding drowned human victims. It also killed millions of dollars’ worth of valuable farm animals.

Some scientists believe climate change affects major storms. They say the warming of Earth’s atmosphere is already making the storms worse. Other scientists have published studies that dispute this.

In two thousand ten, a special committee of the World Meteorological Organization reported on severe storms. The committee’s work appeared in the journal “Nature Geoscience.”  Ten scientists wrote the report. They represented both sides of the debate about climate change. The scientists reached no clear answer about whether rising temperatures on Earth had already intensified storms. Still, they made some predictions.

The committee said the changing climate might cause more powerful ocean storms in the future. It said the overall strength of storms measured by wind speed might increase two to eleven percent by the year twenty-one hundred. And there might be an increase in the number of the most severe storms. But there might be fewer weak and moderate storms.
This forum has been closed.
Comment Sorting
Comments
     
by: Mohamad from: rQhoxpoJRyikTt
10/13/2012 6:04 AM
This is eacxtly what I was looking for. Thanks for writing!


by: Yoshi from: Sapporo
10/06/2012 9:50 PM
It's interesting each hurricane is given a name of people as if it has character. I don' know whether Japan joins the Word Meteorological Organization deciding the ocean storms' name. In Japan, each typhoon gets its name after the chronologial order of birth, just like first, second, third, so on. They are simple and not interesting but there is no limit of numbering.

In ninteen fifty-six, an exra-scale typhoon hit center of Japan and more than three thousands people were killed by high waves flooding over embankments. Low pressure of Typhoon sucked up sea water and happened with the high tide by chance, it produced ocean surge detroying large residential area. This typhoon unusually got the original name of Ise-gulf typhoon after the name of hitting place.


by: walter from: colombia
10/05/2012 3:17 AM
We must take care with our planet, avoid the global warming


by: Maurizio from: Italy
10/04/2012 8:56 AM
This topic has been Treaty and explained very well! Fascinating how the Earth can show its power. As always, the problem must be tackled on several fronts: by information, with houses and buildings more strong, and with prevention with reducing harmful emissions and those that causing atmosphere warming. Warming of huge air masses above big cities or big industrial areas must be reduced also.
Think what we produce every day as trash. Every part of it was been: producted, transported, etc.. and still it needs to be further transported and treated. Can we reduce all of that? -- If you have doubt if human can impact and modify weather think also:
1) about the beginning of the industrial era when cities like London were invaded by smog (smoke + fog).
2) since in the last 15-20 years new cars polluting less, even fog banks are less present on Italian motorways.

Of course we have to work and progress ... but with consciousness!


by: U Nyi Nyi Aung from: Myanmar
10/03/2012 8:08 AM
I like this forum very much.I traveled a lot.I have no enough time to download this forums.What I wanna request you is that you better send this forum both PDF Copy and MP3 Voice File by e.mail to me directly if not tired.My mail is unyinyiaung@gmail.com


by: noor from: Egypt
10/02/2012 10:34 PM
You give us great information

Learn with The News

  • A convoy of peshmerga vehicles is escorted by Turkish Kurds on their way to the Turkish-Syrian border, in Kiziltepe near the southeastern city of Mardin October 29, 2014

    Audio Iraqi Kurdish Fighters Enter Kobani

    Also in the news, Burkina Faso ends efforts to extend its presidential term limit after protests in the capital. Ukraine says the EU will be guarantor in any gas deal with Russia. Myanmar holds a major meeting Friday. And claims of cheating delay SAT results for South Korean and Chinese students. More

  • Ghana Bamboo Bike

    Video Ghana's Bamboo Bikes Hit the Streets

    Bicycle frames are usually made out of materials like carbon fiber, steel or aluminum. But in rural Ghana, a businessman has developed another way to make bicycles from a natural product -- bamboo. The wooden bike parts are sent Ghana to Germany, the Netherlands and Australia. | As It Is More

  • Video Singapore Film Ban Raises Free Speech Issue

    The documentary film, “To Singapore, with Love” tells about political dissidents from Singapore. The film has been shown at public events in Britain, India and Malaysia, among other countries. But one place the movie cannot be seen is Singapore. That is because the government there has banned it. More

  • Believer Benito Martinez (C), dressed as a "devil" wearing a mask, walks around in Almonacid del Marquesado, in central Spain, during the "Endiablada" traditional festival, Feb. 3, 2014.

    Audio A Halloween Special: The Devil is Everywhere ...

    Today we take you to the Dark Side. (insert evil laugh here) We teach expressions that involve the king of evil – the devil. Read on to learn how to “speak of the devil”, “to play devil’s advocate” and to ”make a deal with the devil.” | Words and Their Stories More

  • Orbital Sciences Antares Launch

    Video Questions for NASA after Rocket Explosion

    An unmanned privately-owned rocket bringing supplies to the International Space Station exploded seconds after launch Tuesday night. The accident did not cause any injuries on the ground. However, it has raised questions about efforts by the US space agency NASA to use private companies. More

Featured Stories

  • Obama Halloween

    Audio Halloween Is Big with Kids and Business

    The National Retail Federation says sales of Halloween goods will total about $7.4 billion this year. It says the average American will spend about $77. The group expects 162 million people to celebrate. The NRF predicts 54 million of them will hold Halloween parties. | American Mosaic More

  • A print shows the Second Battle of Bull Run, also called Second Manassas.

    Audio South Defeats North Again at Manassas

    Lincoln named George Pope to lead the Army of Virginia. He wanted to join Pope’s forces with the Army of the Potomac and break through Confederate defenses around Richmond. But General Robert E. Lee decided to hit Pope first. More

  • Star House

    Video Home of Last Comanche Chief Close to Ruins

    One of the most interesting people in U.S. history is Quanah Parker, the last chief of the country’s Comanche Indian tribe. Quanah Parker was the son of a Comanche warrior and a white woman who had been captured by the Indians. Quanah Parker was a fierce fighter. But that ended one day in 1875. More

  • FILE - A veterinarian at the nonprofit Bali Animal Welfare Association gives a rabies shot to a puppy in Kebon Kaja village, Bangli Regency in Bali, Indonesia.

    Audio Mass Vaccination of Dogs Can Eliminate Rabies

    About 70,000 people worldwide die every year of rabies. Rabies is a viral infection that people get mainly through dog bites. Scientists say vaccinating dogs can effectively get rid of rabies outbreaks in dog populations. And this will have a domino effect, fewer humans with rabies. More

  • Methane oxidizing

    Photogallery Small Organisms in Deep Sea Rocks Eat Methane

    The gas methane has been linked to rising temperatures on Earth. But methane does not stay in the atmosphere as long as another “greenhouse gas” -- carbon dioxide. Scientists say both gases trap heat from the sun. They prevent heat from escaping into outer space. More

Practice Your Writing

Confessions of an English Learner BlogConfessions of an English Learner Blog

Tell us About Our Programs