What is a Hurricane?



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What is a Hurricane?


A hurricane is a tropical cyclone where winds reach speeds of more then 119 km per hr. In some hurricanes wind speeds can reach up to and over 289 km per hour. In the Atlantic, tropical storms are known as hurricanes, a Carib Indian word for "big wind." In the West Pacific, they are known as typhoons, a Chinese word meaning "great wind." In Australia they are called a willy-willy, while in the Indian Ocean they are simply known as tropical cyclone. Where cyclone is a Greek word meaning, "coil." Normally hurricanes have a life span of 1-30 days in length. After the 30-day mark, the extended contact with cold waters and land surfaces, the hurricanes will slowing die of and become a tropical storm.

(http://www.todossantos-baja.com/todos-santos/hurricanes/hurricane-adolph-2001.jpg)


Formation of Hurricanes


Tropical depression and tropical storm are the first two stages that a cyclone will reach while attaining hurricane force. Hurricanes start to form by gathering tropical storms together over the sea. Moist air and thermal energy is taken in by the low-pressure centre from the oceans surface, and then air is lifted by the process of convection, while high pressure in the atmosphere pushes it outward. The going round of the wind currents will spin the clouds into a tight coil, which will the make the winds stronger, which will then become gale force, making the depression into a hurricane. A mature hurricane has a power that will extend over 500 mi (805 km) in diameter. Low central pressure will result in the surface air spiralling inward cyclonically (Counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere) making circle that is about 30km in size that will encircle the hurricanes eye. The rim of the circle is known as the eye wall, where the spiralling, moist air is then forced up, causing heat to be released. Then by reaching tens of thousands of feet above the ground, the air is pushed towards the storms edges, which then creates the spirals clouds that we see on satellite images. The eye wall has the heaviest precipitation and the highest clouds because of upward velocity of air and subsequent condensation. Also the eye wall has the highest and maximum wind speed of the hurricane, because of the push of pressure outward. On the other hand the eye of the hurricane is completely different, with no wind and little precipitation and is usually no clouds, leaving the sky blue. Sinking currents at the hurricane's core lead to warmer temperatures in the eye of more then 10°F to 15°F (5°C–8°C) then the air surrounding the eye.

(http://www1.ncdc.noaa.gov/pub/data/images/four-hurricanes-19980926-g84kmir.gif)


Movement and Occurrence of Hurricanes

At the early stages of a hurricane, they travel east bound at about 16 km/hr. As they progress, they will start to turn towards the poles as they reach the western margins of the oceans at 20° to 30° lat., but there are more complex tracks are common. In the northern hemisphere, hurricanes tend to form over the Atlantic Ocean and as they grow more mature they will go westward. Mexico also has hurricanes that form of the west coast that will move north-eastward up the coast. Only 3.5 hurricanes on average will mature and reach the east coast of North America. One of the three hurricanes usually will come from the Caribbean Sea or the Gulf of Mexico. On the east side of North America hurricanes usually form from June to November. While Hurricanes in the Pacific prefer May through to December. In the Southern Hemisphere the hurricane season is December to April. The reason the hurricane seasons are when they are, is because for a hurricane to form they need warm water and during these months that’s when the water is the warmest. Most commonly you will see a picture of a hurricane though satellite pictures, but airplanes are still the best way to track hurricanes, only by flying directly through the storm can you tell how quick it’s moving, how large it is and how strong the winds are.


(http://www.srh.noaa.gov/jax/research/hurricanes/history/1898/Graphs/Graph1.GIF)



Damage Caused by Hurricanes


The number one cause of loss of life and damage done to property is the winds of the hurricane. Another big factor the flooding caused torrential rains that are caused. To determine the severity of a hurricane you would use the Saffir-Simpson scale, which measures the damage that was done. It measures/classifies hurricanes on a ladder from category 1 (minimal), through category 2 (moderate), category 3 (extensive), and category 4 (extreme), to category 5 (catastrophic). Since the system was introduced, there have been only two category 5 hurricanes to hit the states, one in Florida in 1935 killing over 600 people and in Mississippi in 1969 killing 256 people and damage of 1.4 billons dollars US. There have been less than ten, category 5 hurricanes to hit in the Atlantic Ocean. Even when a hurricane dies down to a tropical storm, it can still cause major damage and flooding, as Hurricane Agnes did in 1972. Many programs have been set up to try and stop a hurricane in its early stages. Most recently, damage-mitigation steps have been put forward including better warning systems involving real-time satellite imagery. Within 24-36 hours a hurricane warning is issued if there is threat of a hurricane conditions. When hurricane conditions (winds greater than 74 mph/119 kph or dangerously high water and rough seas) are expected in 24 hours or less, a hurricane warning is issued.

(http://www.eaglesnest.net/weather/saffirsimpson.gif)




Hurricane Names
Since there can be more then one hurricane brewing up in the ocean, they use a name system, so it won’t be so confusing and you can tell which hurricane they are talking about. Names are ready to be used and are made up by official storm trackers all over the world. The names that are chosen are used in a six-year rotation, unless they are retired. Hurricanes names that become retired are really big in size and cause quite a bit of destructive.



Retired Names:

Agnes
Alicia
Allen
Andrew
Anita
Audrey
Betsy
Bob

Camille
Carla
Carmen
Celia
Cesar
Cleo
Connie
David

Diana
Donna
Elena
Fran
George
Gilbert
Gloria
Hortense

Janet
Joan
Louis
Marilyn
Mitch
Opal
Roxanne


(http://www.goes.noaa.gov/EVENTS/EG41.GIF)



(http://envsc.edcc.edu/hurricanes.jpg)


The Six-Year List of Hurricane Names For Atlantic Storms


2001
Allison
Barry
Chantal
Dean
Erin
Felix
Gabrielle
Humberto
Iris
Jerry
Karen
Lorenzo
Michelle
Noel
Olga
Pablo
Rebekah
Sebastien
Tanya
Van
Wendy

2002
Arthur
Bertha
Cristobal
Dolly
Edouard
Fay
Gustav
Hanna
Isidore
Josephine
Kyle
Lili
Marco
Nana
Omar
Paloma
Rene
Sally
Teddy
Vicky
Wilfred

2003
Ana
Bill
Claudette
Danny
Erika
Fabian
Grace
Henri
Isabel
Juan
Kate
Larry
Mindy
Nicholas
Odette
Peter
Rose
Sam
Teresa
Victor
Wanda

2004
Alex
Bonnie
Charley
Danielle
Earl
Frances
Gaston
Hermine
Ivan
Jeanne
Karl
Lisa
Matthew
Nicole
Otto
Paula
Richard
Shary
Tomas
Virginie
Walter

2005
Arlene
Bret
Cindy
Dennis
Emily
Franklin
Gert
Harvey
Irene
Jose
Katrina
Lee
Maria
Nate
Ophelia
Philippe
Rita
Stan
Tammy
Vince
Wilma

2006
Alberto
Beryl
Chris
Debby
Ernesto
Florence
Gordon
Helene
Isaac
Joyce
Keith
Leslie
Michael
Nadine
Oscar
Patty
Rafael
Sandy
Tony
Valerie
William

(http://www.datanation.com/images/dh.gif)

Tropical Cyclones (hurricanes)
by: Lee Rafuse and Corey Rafuse

(http://www.north-topsail-beach.org/hurrican.htm)

2003-05-04

Global Geography 12

Mr. Wohlmuth

Works Cited:
“All About Hurricanes.” Scholastic. (1 May 2003)

http://teacher.scholastic.com/activities/wwatch/hurricanes/extreme/trivia.htm

“Hurricanes.” InfoPlease.com (3 May 2003)



http://www.infoplease.com/spot/hurricanes.html

“Natural Disasters, Hurricanes.” Federal Emergency Management Agency (3 May 2003)



http://www.fema.gov/kids/hurr.htm

“Questions and Answers About Hurricanes.” National Severe Storms Laboratory (1 May 2003)



http://www.nssl.noaa.gov/edu/hurricane
Directory: Projects -> Hurricane
Projects -> Terminal Decision Support Tool Systems Engineering Graduate Capstone Course Aiman Al Gingihy Danielle Murray Sara Ataya
Projects -> Rajinder Sachar Committee
Projects -> Cape Lookout National Seashore Historic Resource Study By
Projects -> Cape Lookout National Seashore Historic Resource Study By
Projects -> Revolutionizing Climate Modeling – Project Athena: a multi-Institutional, International Collaboration
Projects -> General Information
Projects -> Press Information
Projects -> 1 Introduction 3 2 Designing an Embedded System 4
Projects -> Published as: Sugrue, B. & Clark, R. E. (2000), Media Selection for Training. In S. Tobias & D. Fletcher (Eds.), Training & Retraining: a handbook for Business, Industry, Government and the Military. New York: Macmillan
Hurricane -> Navigating the Hurricane Highway Understanding Hurricanes With Google Earth

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