Natural Hazards
Programme 4: Hurricane

Aims

To describe and explain the hurricane that hit New Iberia in the state of Louisiana, USA
To illustrate the effects and consequences of the hurricane
To explore the relationship between the hurricane and the effect on human activity

00.00–01.44 Introduction to Louisiana in the deep south of America and the problems of hurricanes
01.45–02.41 A brief explanation of hurricanes and their causes
02.42–05.02 The impact of hurricane Lili on one small town, New Iberia in October 2002 – the population is advised to leave
05.03–08.44 Individual stories of people who decided to stay during the storm – includes dramatic footage
08.45–10.39 Water is just as big a problem as wind during a hurricane, particularly along the coast and in low-lying areas – includes individual experiences
10.40–13.01 Measures used to try to protect the land against hurricanes and tidal surges
13.02–14.46 Concerns about the impact of a hurricane on the region's major city, New Orleans should a major storm head in that direction
14.47–end Credits

Curriculum Relevance

Hurricanes as hazards and the effects of and responses to hurricanes
A case study of one hurricane and its impact on human activity in an MEDC (more economically developed country)

Background

What are hurricanes?
A hurricane is a tropical cyclone consisting of swirling masses of air moving in a general westerly direction and occurs in the Caribbean and the Gulf of Mexico. It is a very intense 'Depression' with extremely low atmospheric pressure. This gives rise to winds of great force (Force 12 on the Beaufort Scale – 150km per hour or over), which are extremely destructive. The winds circulate round the centre or eye of the storm in an anticlockwise direction (north of the equator). The eye of a hurricane is about 25km in diameter and is often very calm. The whole of the hurricane has a diameter of between 150km to 300km. It is accompanied by dense black clouds, torrential rainfall (over 250mm per day), often thunder and lightning and storm surges that cause flooding in coastal areas.

Where and when do they occur?
Tropical cyclones are found mostly 10º to 20º to the north or south of the equator. They are called by different names depending on where they occur – typhoons in the China Sea, cyclones in the Bay of Bengal, the willy-willies off north-western Australia and hurricanes in the Gulf of Mexico. They develop in autumn north of the equator over warm tropical seas and the months of greatest frequency are September and October.

Why do hurricanes happen in the Gulf of Mexico?
The Mexican Gulf lies in the Tropics where the trade wind air masses converge. In autumn, the warm tropical water of the Mexican Gulf exceeds temperatures of 26ºC and an enormous amount of water vapour is formed. The air masses over the oceans have very moist lower layers and drier upper layers of air. When the two meet the moist air rises very rapidly over the drier air and an area of very low pressure develops, creating very unstable atmospheric conditions. These conditions are the origins of a hurricane.

What was the impact of the hurricane on New Iberia in October 2002?
The national weather service called this hurricane, Hurricane Lili and it was forecast to be the most devastating storm for a very long time (category 4 on the hurricane intensity scale). The government urged people to evacuate and half the population took the advice and fled north. This sort of advice is not given lightly – the average cost of a family to evacuate is about 500 dollars and when businesses evacuate the average cost is 17,000 dollars.

In the event, Lili was a category 2 hurricane but a great deal of damage was caused. It left behind a trail of devastation from wind and flood damage. Strong winds toppled trees onto houses and into roadways, tore roofs from houses and blew out windows. The wind and driving rain flattened sugar cane fields throughout southern Louisiana. Protection levees failed in the south-eastern part of the state and all oil production in the Gulf of Mexico was temporarily stopped.

Water is just as big a problem as winds during a hurricane, particularly along the coast and in low-lying areas. The worst water damage comes from a tidal or storm surge. As the hurricane sweeps towards the coast the onshore winds drive a wall of water inland. After the surge, the floods can take days to subside. The tidal surge from Hurricane Lili completely disrupted the ecology of the wetlands. River beds were churned up, vegetation was ripped out, and the debris was dumped on the sea bed. Lili like all other hurricanes ruined, for several months, the delicate environmental balance.

The total damage was estimated to be 860 million dollars. However, despite all the damage to the landscape only one fatality was recorded.

What can be done to protect areas like Louisiana against the effects of hurricanes?
How to even begin to protect the land against the winds and the tidal surges has always been a major engineering challenge. In Louisiana, the most threatened stretches of the coast have actually been walled up. There are thousands of kilometres of these walls known as levees and a whole network of floodgates behind which boats can be held safe during hurricane attacks.

Activities

1. Using the programme and the information contained in the background information complete the table below about Hurricane Lili:

Hurricane
(location)

Description of Hurricane

Effects and Damage

Reducing the Hazard

2. Working in small discussion groups imagine that you are officials from New Iberia and you have been given the responsibility of planning for future hurricanes. Using the background information above and the television programme:

What would your strategy be under the following headings - Prediction; Protection; Education and Training; Self-reliance.
Give a brief presentation of your conclusions to the rest of the class. What are the similarities and differences between your decisions and those of the other groups?
Design a poster giving advice to people on how to prepare for a hurricane, what to do during a hurricane and what to be aware of afterwards.

3.Louisiana is in an MEDC (more economically developed country); Bangladesh is an LEDC (less economically developed country). Both suffer from tropical cyclones – hurricanes in Louisiana and cyclones in Bangladesh. Below is a brief account of a cyclone that hit the island of Moheshkhali off the coast of Bangladesh in April 1991.

'When a cyclone hit Moheshkhali off the coast of Bangladesh in April 1991 the effects on the island were devastating – houses were destroyed, members of families died; valuables and possessions were lost; food supplies were washed away; clean water was contaminated; some families stayed in their houses during the cyclone while others went to the storm shelters; fishing boats were destroyed. The cyclone brought a tidal surge of 6 metres to the island. Over 12,000 people lost their lives. About 28,000 others were injured, 48,000 cattle died and the economic damage was estimated at £60 million.'

Describe and explain the similarities and differences between this disaster and the hurricane that struck New Iberia?

Links

This web page contains links to other websites that are neither controlled nor maintained by Channel 4 Television. Channel 4 Television is not responsible for the content of these sites and does not necessarily endorse the material on them.

www.aoml.noaa.gov/hrd/tcfaq/D1.html
Frequently asked questions about hurricanes, typhoons and tropical cyclones. Includes an explanation of the hurricane intensity scale – Level: teachers and students

www.fema.gov/kids/hurr.htm
The Federal Emergency Management Agency, FEMA for Kids. A site designed for young people giving comprehensive information about all aspects of hurricanes – Level: students

www.nhc.noaa.gov/2002lili.shtml
The National Hurricane Centre giving a detailed account of Hurricane Lili from 21 September to 4 October 2002 – Level: teachers