How Hurricanes are Formed
Hurricanes develop from belts of low pressure called easterly waves. These regions of low pressure occur in ocean winds called trade winds. On certain occasions, the easterly waves form into tropical depressions, which are characterized by a group of thunderstorms with cyclonic winds of up to thirty one miles per hour. The next stage in development is a tropical storm, with winds of up to seventy three miles per hour. Any wind speed higher than that and it is a hurricane.
The fuel that powers hurricanes is derived from latent heat from the condensing of water vapor. Thunderstorms can produce up to ten inches of rain per day, and thus produce an incredible amount of energy, up to 24 x 10¹¹ kilowatt hours per day on average. This is the equivalent of how much power most industrialized nations use in one year (such as the United States).
Winds swirl around the eye, the calm center of the hurricane. The eye has a diameter of about twenty miles across and has very few winds or clouds. Surrounding the eye are storm clouds called wall clouds. It is within these clouds that the heaviest rains and strongest winds occur. These wind speeds are kept up by the differences in horizontal pressure between the eye and outer regions of the storm.
Initially, when a hurricane forms, its forward movement is very slow (fifteen miles per hour), but as it gets farther away from the equator, its speed increases up to sixty miles per hour in middle latitudes. But in addition to gaining speed as is moves away from the equator, it also begins to die. Eventually it looses its source of power as it passes over land and gets ripped apart by friction. Hurricanes usually only last between five and ten days.
The Essay on Trade Winds Hurricane Storm Tropical
... surrounding winds. Stronger winds wrap themselves more tightly around the eye so that it becomes smaller. The average eye of a hurricane is about twenty miles ... the heat from the sun evaporates to form vast storm clouds. As the warm air rises, the cooler air replaces it ... There, it can be faster than six hundred miles per hour. You cannot see a hurricane all at once, unless you " re looking ...
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What are hurricanes made of?In: Hurricanes Typhoons and Cyclones [Edit categories] |
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hurricanes are made of hot water and air pressure some hurricanes are bigger than a whole states and province! but canada doesnt have to worry that much because of their cold water form pacific a hurricane can last up to 10 years and more like a hurricane will never break but eventually it will its not a beutiful thing good thing we have setalites now we know where hurricanes are 1 huricane is near the cape of good hope and south east of america and they hav been up for like 5 years now we dont have to worry bout the other ones yet.
some people predict that a giant hurricane will destroy earth at 2012 dec.21 many predict something else.the mayan calender predicts that 2012 dec 21 will be last day of the wrld. so many religons so many cultures theres lots of predictions of what will happen in 2012 the end is near.
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How Do Hurricanes Form? |
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Hurricane Fran. Image made from GOES satellite data. |
Hurricanes are the most awesome, violent storms on Earth. People call these storms by other names, such as typhoons or cyclones, depending on where they occur. The scientific term for all these storms is tropical cyclone. Only tropical cyclones that form over the Atlantic Ocean or eastern Pacific Ocean are called “hurricanes.” Whatever they are called, tropical cyclones all form the same way. | |
Tropical cyclones are like giant engines that use warm, moist air as fuel. That is why they form only over warm ocean waters near the equator. The warm, moist air over the ocean rises upward from near the surface. Because this air moves up and away from the surface, there is less air left near the surface. Another way to say the same thing is that the warm air rises, causing an area of lower air pressure below. |
The Term Paper on Late Season Hurricanes Hurricane Storms
Natural Disasters This being my senior project I wanted to look at a topic that I found interesting. Even though I find most topics in the fields interesting, none catch my attention better than natural disasters. I have always found disasters intriguing and have wanted to know more about them. The disaster that I found most interesting were Hurricanes. The thought of those storms with their power ...
A cumulonimbus cloud. A tropical cyclone has so many of these, they form huge, circular bands. |
Air from surrounding areas with higher air pressure pushes in to the low pressure area. Then that “new” air becomes warm and moist and rises, too. As the warm air continues to rise, the surrounding air swirls in to take its place. As the warmed, moist air rises and cools off, the water in the air forms clouds. The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the surface. Storms that form north of the equator spin counterclockwise. Storms south of the equator spin clockwise. This difference is because of Earth’s rotation on its axis.As the storm system rotates faster and faster, an eye forms in the center. It is very calm and clear in the eye, with very low air pressure. Higher pressure air from above flows down into the eye.If you could slice into a tropical cyclone, it would look something like this. The small red arrows show warm, moist air rising from the ocean’s surface, and forming clouds in bands around the eye. The blue arrows show how cool, dry air sinks in the eye and between the bands of clouds. The large red arrows show the rotation of the rising bands of clouds.When the winds in the rotating storm reach 39 mph, the storm is called a “tropical storm.” And when the wind speeds reach 74 mph, the storm is officially a “tropical cyclone,” or hurricane.Tropical cyclones usually weaken when they hit land, because they are no longer being “fed” by the energy from the warm ocean waters. However, they often move far inland, dumping many inches of rain and causing lots of wind damage before they die out completely.Tropical cyclone categories: |
Category | Wind Speed (mph) | Damage at Landfall | Storm Surge (feet) |
1 | 74-95 | Minimal | 4-5 |
The Essay on Boats Storm Wind Boat
We had a terrific day planned. It was a beautiful morning, not a cloud in the sky and not much traffic on the road. The forecast was sunny with a high of 90 degrees, only a slight chance of an afternoon thunderstorm. We packed the coolers with a variety of foods, from snacks to desserts. The arrangements were scheduled for 8: 00 a. m. in a small city of Frenchtown, New Jersey. There were fifteen ...
2 | 96-110 | Moderate | 6-8 |
3 | 111-130 | Extensive | 9-12 |
4 | 131-155 | Extreme | 13-18 |
5 | Over 155 | Catastrophic | 19+ |
Here is a movie of Hurricane Katrina, which struck the coast of Louisiana and Alabama on August 29, 2005, as a Category 3. This movie was made from images taken by the GOES weather satellite. In the movie you can see the storm starting to form in the Atlantic on August 24 and becoming more and more organized as it moves over the warm waters of the Gulf of Mexico. |
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| How Are Hurricanes Formed?
Left: Image produced by Hasler, Pierce, Palaniappan & Manyin of NASA’s Goddard Laboratory for Atmospheres – Data from NOAA Hurricanes begin as tropical storms over the warm moist waters of the Atlantic and Pacific Oceans near the equator. (Near the Phillippines and the China Sea, hurricanes are called typhoons.) As the moisture evaporates it rises until enormous amounts of heated moist air are twisted high in the atmosphere. The winds begin to circle counterclockwise north of the equator or clockwise south of the equator. The reatively peaceful center of the hurricane is called the eye. Around this center winds move at speeds between 74 and 200 miles per hour. As long as the hurricane remains over waters of 79F or warmer, it continues to pull moisture from the surface and grow in size and force. When a hurricane crosses land or cooler waters, it loses its source of power, and its wind gradually slow until they are no longer of hurricane force–less than 74 miles per hour. Hurricanes over the Atlantic often begin near Africa, drift west on the Trade Winds, and veer north as they meet the prevalling winds coming eastward across North America. Hurricanes over the Eastern Pacific begin in the warm waters off the Central American and Mexican coasts. Eastern and Central Pacific storms are called “hurricanes.” Storms to the west of the International Date Line are called “typhoons.” Because of the destructive force of hurricanes during late summer and early autumn, scientists constantly monitor them with satellites and sometimes even fly airplane surveillance to keep track of tropical storms that might develop into hurricanes. |
The Essay on The major ocean surface current patterns
An ocean surface current is a constantly directed and continuous movement or flow of ocean water. Major ocean surface current patterns are powered by the wind. However, these patterns are also largely influenced by other factors such as the Corolis effect, which is the deflection of the water to the direction of the wind, the differences in heating across the globe, and the structure of the ...
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How are Hurricanes Created?The birth of a hurricane requires at least three conditions. First, the ocean waters must be warm enough at the surface to put enough heat and moisture into the overlying atmosphere to provide the potential fuel for the thermodynamic engine that a hurricane becomes. Second, atmospheric moisture from sea water evaporation must combine with that heat and energy to form the powerful engine needed to propel a hurricane. Third, a wind pattern must be near the ocean surface to spirals air inward. Bands of thunderstorms form, allowing the air to warm further and rise higher into the atmosphere. If the winds at these higher levels are relatively light, this structure can remain intact and grow stronger: the beginnings of a hurricane! Often, the feature that triggers the development of a hurricane is some pre-existing weather disturbance in the tropical circulation. For example, some of the largest and most destructive hurricanes originate from weather disturbances that form as squall lines over Western Africa and subsequently move westward off the coast and over warm water, where they gradually intensify into hurricanes. Hurricane winds in the northern hemisphere circulate in a counterclockwise motion around the hurricane’s center or “eye,” while hurricane winds in the southern hemisphere circulate clockwise. The eye of a hurricane is relatively calm. It is generally 20 to 30 miles wide (the hurricane istself may extend outward 400 miles).
The most violent activity takes place in the area immediately around the eye, called the “eyewall”. At the top of the eyewall (up to 50,000 feet), most of the air is propelled outward, increasing the air’s upward motion. Some of the air, however, moves inward and sinks into the eye, creating a cloud-free area. Tropical Rainfall Measuring MissionHurricanes are huge heat engines, converting the warmth of the tropical oceans and atmosphere into wind and waves. The heat dissipates as the system moves toward the poles, sometimes causing a great deal of hardship for people living along the vulnerable coastlines. NASA scientists are using the TRMM satellite to understand which parts of a hurricane produce rainfall and why. In addition, TRMM may answer the question of how much latent heat or “fuel” hurricanes release into the atmosphere and whether they affect global weather patterns. Most importantly to people endangered by hurricanes, TRMM will add to the knowledge needed to improve computer-based weather modeling. With this data, meteorologists may be more able to precisely predict the path and intensity of these storms. | |
The Essay on Hurricane Floyd Winds Reach
... a tropical storm if the winds reach speeds of 74 mph or less. Then finally a the storm can be bumped up into a hurricane ... dollars to repair. Even if the hurricane doesn't cause a lot of damage, the storm surge will. Storm surge is the great tidal waves ... normally in the Gulf of Mexico or the Atlantic Ocean. The hurricane season is the six month time period from June-November. ...
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Hurricane Movement
How do we know which way a hurricane will go? Forecasters track hurricane movements and predict where the storms will travel as well as when and where they will reach land. While each storm will make its own path, the movement of every hurricane is affected by a combination of the factors described below.
Hurricanes are steered by global winds. These winds, called trade winds, blow from east to west in the tropics. They carry hurricanes and other tropical storms from east to west. In the Atlantic, storms are carried by the trade winds from the coast of Africa where they typically form westward to the Caribbean and North American coasts. When the trade winds are strong it is easier to predict where the storm will travel. When they are weak it’s more difficult.
After a hurricane crosses an ocean and reaches a continent, the trade winds weaken. This means that the Coriolis Effect has more of an impact on where the storm goes. In the Northern Hemisphere the Coriolis Effect can cause a tropical storm to curve northward.
When a storm starts to move northward, it leaves the trade winds and moves into the westerlies, the west to east global wind found at mid-latitudes. Because the westerlies move in the opposite direction from trade winds, the hurricane can reverse direction and move east as it travels north.
High pressure systems can also affect the path of storms. In the Atlantic Ocean, the Bermuda High affects the path of hurricanes. When the storms are carried west by the trade winds, they are pushed north around the edge of the high pressure area.
The Essay on Hurricanes Hurricane People Winds
Hurricane, name applied to migratory tropical cyclones that originate over oceans in certain regions near the equator, and particularly to those arising in the West Indian region, including the Caribbean Sea and the Gulf of Mexico. Hurricane-type cyclones in the western Pacific are known as typhoons. Hurricanes are high winds that move in a circular motion, around an eye (a low pressure center of ...
Although these factors add up to a typical hurricane path that travels west and then bends poleward, there are other factors that affect a hurricane’s path and complex hurricane tracks are common too.
Last modified March 31, 2009 by Lisa Gardiner.
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Movement and Occurrence of Hurricanes
Hurricanes and typhoons usually move westward at about 10 mph (16 kph) during their early stages and then curve poleward as they approach the western boundaries of the oceans at 20° to 30° lat., although more complex tracks are common. In the Northern Hemisphere, incipient hurricanes usually form over the tropical Atlantic Ocean and mature as they drift westward; hurricanes also form off the west coast of Mexico and move northeastward from that area. Between June and November, an average of six tropical storms per year mature into hurricanes along the east coast of North America, often over the Caribbean Sea or the Gulf of Mexico. Two of these storms will typically become major hurricanes (categories 3 to 5 on the Saffir-Simpson scale).
One to three hurricanes typically approach the U.S. coast annually, some changing their direction from west to northeast as they develop; as many as six hurricanes have struck the United States in one year. Hurricanes and typhoons of the N Pacific usually develop sometime between May and December; typhoons and tropical cyclones of the Southern Hemisphere favor the period from December through April; Bay of Bengal and Arabian Sea tropical cyclones occur either between April and June or September and December, the times of the onset and retreat of the monsoon winds.
Sections in this article:
* Introduction
* Formation of Hurricanes
* Movement and Occurrence of Hurricanes
* Damage Caused by Hurricanes
* Bibliography
Read more: hurricane: Movement and Occurrence of Hurricanes — Infoplease.com http://www.infoplease.com/ce6/weather/A0858708.html#ixzz1GgFn2yNt
hurricane
hurricane, tropical cyclone in which winds attain speeds greater than 74 mi (119 km) per hr. Wind speeds reach over 190 mi (289 km) per hr in some hurricanes. The term is often restricted to those storms occurring over the N Atlantic Ocean; the identical phenomenon occurring over the W Pacific Ocean is called a typhoon; around Australia and over the Indian Ocean, a tropical cyclone. Hurricanes have a life span of 1 to 30 days. They weaken and are transformed into extratropical cyclones after prolonged contact with the colder ocean waters of the middle latitudes, and they rapidly decay after moving over land areas.
Sections in this article:
* Introduction
* Formation of Hurricanes
* Movement and Occurrence of Hurricanes
* Damage Caused by Hurricanes
* Bibliography
Read more: hurricane — Infoplease.com http://www.infoplease.com/ce6/weather/A0824612.html#ixzz1GgG3FGkj
Formation of Hurricanes
A cyclone that eventually reaches hurricane intensity first passes through two intermediate stages known as tropical depression and tropical storm. Hurricanes start over the oceans as a collection of storms in the tropics. The deepening low-pressure center takes in moist air and thermal energy from the ocean surface, convection lifts the air, and high pressure higher in the atmosphere pushes it outward. Rotation of the wind currents tends to spin the clouds into a tight curl; as the winds reach gale force, the depression becomes a tropical storm. The mature hurricane is nearly circularly symmetrical, and its influence often extends over an area 500 mi (805 km) in diameter.
As a result of the extremely low central pressure (often around 28.35 in./960 millibars but sometimes considerably lower, with a record 25.69 in./870 millibars registered in a 1979 NW Pacific typhoon) surface air spirals inward cyclonically (counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere), converging on a circle of about 20 mi (30 km) diameter that surrounds the hurricane’s “eye.” The circumference of this circle defines the so-called eye wall, where the inward-spiraling, moisture-laden air is forced aloft, causing condensation and the concomitant release of latent heat; after reaching altitudes of tens of thousands of feet above the surface, this air is finally expelled toward the storm’s periphery and eventually creates the spiral bands of clouds easily identifiable in satellite photographs.
The upward velocity of the air and subsequent condensation make the eye wall the region of heaviest precipitation and highest clouds. Because the outward increase in pressure is greatest there, the eye wall is also the region of maximum wind speed. By contrast, the hurricane eye is almost calm, experiences little or no precipitation, and is often exposed to a clear sky. Temperatures in the eye are 10°F to 15°F (5°C–8°C) warmer than those of the surrounding air as a result of sinking currents at the hurricane’s core.
Sections in this article:
* Introduction
* Formation of Hurricanes
* Movement and Occurrence of Hurricanes
* Damage Caused by Hurricanes
* Bibliography
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Damage Caused by Hurricanes
High winds are a primary cause of hurricane-inflicted loss of life and property damage. Another cause is the flooding resulting from the coastal storm surge of the ocean and the torrential rains, both of which accompany the storm. The Saffir-Simpson scale is the standard scale for rating the severity of a hurricane as measured by the damage it causes. It classifies hurricanes on a hierarchy from category 1 (minimal), through category 2 (moderate), category 3 (extensive), and category 4 (extreme), to category 5 (catastrophic).
A supertyphoon is equivalent to a category 4 or 5 hurricane.
Only three category-5 storms have hit the United States since record-keeping began—the 1935 Labor Day hurricane, which devastated the Florida Keys, killing 600; Hurricane Camille in 1969, which ravaged the Mississippi coast, killing 256; and Andrew in 1992, which leveled much of Homestead, Fla. Hurricane Katrina in 2005 was a category-5 storm at peak intensity over the central Caribbean, Mitch in 1998 was a category-5 storm at its peak over the W Caribbean, and Gilbert in 1988 was a category-5 storm at its peak. Gilbert was the strongest Atlantic tropical cyclone of record until Wilma in 2005, which was at its peak while category-5 storm over the W Caribbean. The 1970 Bay of Bengal tropical cyclone killed some 300,000 persons, mainly by drowning, and devastated Chittagong (now in Bangladesh); some 130,000 died when a cyclone struck Myanmar along the Andaman Sea in 2008. The deadliest U.S. hurricane was the 1900 Galveston storm, which killed 8,000–12,000 people and destroyed the city. Hurricane Katrina (2005), one of the worst natural disasters in U.S. history, was economically the most destructive U.S. storm, devastating the SW Mississippi and SE Lousiana coasts, flooding New Orleans, killing some 1,200 people, and leaving hundreds of thousands homeless. Hugo (1989) in South Carolina and Opal (1995) and Charley, Ivan, and two others (2004) in Florida, and Rita (2005) in Louisiana and Texas also caused billions of dollars worth of damage. Weak hurricanes can still cause major flooding and damage, even when downgraded to a tropical storm, as did Hurricane Agnes (1972).
To decrease such damage several unsuccessful programs have studied ways to “defuse” hurricanes in their developing stages; more recent hurricane damage-mitigation steps have included better warning systems involving real-time satellite imagery. A hurricane watch is issued when there is a threat of hurricane conditions within 24–36 hours. A hurricane warning is issued when hurricane conditions (winds greater than 74 mph/119 kph or dangerously high water and rough seas) are expected in 24 hours or less.
Sections in this article:
* Introduction
* Formation of Hurricanes
* Movement and Occurrence of Hurricanes
* Damage Caused by Hurricanes
* Bibliography
Read more: hurricane: Damage Caused by Hurricanes — Infoplease.com http://www.infoplease.com/ce6/weather/A0858709.html#ixzz1GgGGT4ao
Bibliography
See B. Tufty, One Thousand One Questions Answered about Hurricanes, Tornados, and Other Natural Air Disasters (1987); R. A. Pielke, The Hurricane (1990); J. Barnes, Florida’s Hurricane History (1998); J. Barnes, North Carolina’s Hurricane History (1998); D. Longshore, Encyclopedia of Hurricanes, Typhoons, and Cyclones (1998); E. Larson, Isaac’s Storm (1999).
Sections in this article:
* Introduction
* Formation of Hurricanes
* Movement and Occurrence of Hurricanes
* Damage Caused by Hurricanes
* Bibliography
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2007, Columbia University Press. All rights
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