Natural Hazards Year 9 Geography Natural Hazards Year 9 Geography

Natural Hazards Year 9 Geography - PowerPoint Presentation

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Natural Hazards Year 9 Geography - PPT Presentation

5A1 Investigating Australias Physical Environments Syllabus Agenda the nature of the natural hazard in Australia the geographical processes involved the impacts of the natural hazard ID: 812923

tropical cyclone damage cyclones cyclone tropical cyclones damage natural activity australia hazard government impacts storm emergency hazards air wind




Presentation Transcript


Natural Hazards

Year 9 Geography


Investigating Australia’s Physical Environments


Syllabus Agenda


nature of the natural hazard in Australia


geographical processes involved


impacts of the natural hazard:





responsibility and responses of individuals, groups and various levels of government to the impact of the natural hazard


Natural hazards in Australia

Describe the range of natural hazards in Australia and their consequences including:

bushfires, droughts, earthquakes, floods, storms and tropical cyclones.

For at least one natural hazard:

The nature of the natural hazard in Australia.

The geographical processes involved.

The impacts of the natural hazard: economic,

environmental and social.

The responsibility and responses of individuals, groups and

various levels of government to the impact of the natural



Natural hazards

A natural hazard is when the forces of nature combine to become destructive including tropical cyclones and storms, floods, bushfires, droughts, earthquakes, landslides and tsunamis.




Create a


on natural hazards.Include a definition and anillustration for each natural hazard listed above.


Types of natural hazards

Natural hazards can be separated into two main categories:

1. Those related to weather and climatic factors – drought, flood, heat waves, bushfires, strong winds, storms, cyclones and tornadoes.

2. Those related to movements in the earths crust – landslides, earth tremors, earthquakes and tsunamis.


Types of impacts

Three main categories

Social impacts – loss of life, stresses placed on families and people, destruction of community structures and facilities.

Economic impacts – loss of income for people or damage to an industry, loss and destruction of property, insurance losses.

Environmental impacts – destruction

of natural and human environment,

death of and injury to wildlife,

changes to environments.


Building damage in Australia


Using figure 2.4

Name the three most costly natural hazards in terms of building damage in Australia





Tropical cyclones

A tropical cyclone is an intense tropical storm that develops over warm oceans between 5° and 20° north or south of the Equator.


Tropical Cyclones (TC) in




form over the northern parts of Australia in the months from November to April.

They affect areas North of Perth along the coasts of Western Australia and the Northern Territory, the Queensland coastline and the far north coast of New South Wales.


Go to


Download the Cyclone worksheet

Complete the worksheet

using the



website(a) Activity


Key geographical processes in cyclone development

They form in the band between 5° and 22° N and S of the Equator over oceans with a water temperature greater than 26.5°C.

Warm moist air over these oceans rises, causing low pressure systems to develop.

The rising air forms clouds, which release heat, causing the air to rise further, leading to a tropical storm.


How tropical cyclones develop

Tropical cyclones develop in the


regions of the world.

Heat from the sun causes

warm, moist air to rise

into the atmosphere.

As the air rises, a low-pressure system forms and condensation occurs, which releases further latent heat causing the



rise further

into the atmosphere.

If the

air pressure

in the upper atmosphere is


, then the rising column of

warm air will spiral outwards

in the upper atmosphere and



rush from the surface to replace it

, forming a tropical cyclone.


Cyclones (Hazards Disasters & Survival)

Click view movie Social Science / Geography / Cyclones


Tropical cyclone conditions

Winds can reach and exceed speeds of 120 kilometres per hour (km/h), with gusts exceeding 170 km/h. Winds at these speeds can do great damage to property, including causing boats to slip from their moorings, downing trees and even ripping roofs and walls from buildings.

Power lines are often damaged in tropical cyclones, causing power outages.

High levels of rainfall cause flooding in some areas.


Storm Surges – another risk from tropical cyclones

Storm surges are a rise in sea level caused by high winds pushing water towards shore and lower atmospheric pressure.

Storm surges are affected by:

wind speeds within the cyclone,

the speed at which the cyclone is travelling towards the coast,

The angle at which the cyclone crosses the coast,

the shape of the sea floor, and

local topography. When high tide comes to an area at the same time as a storm surge, a phenomenon known as a storm tide can cause the sea level to be even higher. This can threaten areas that would usually be safe from a high tide, causing flooding and sea damage.


Five categories of tropical cyclones

Little damage to houses and other buildings. Some damage to crops and other vegetation. Wind speeds less than 125 km/h.

Minor damage to houses and other buildings. Damage to signs, trees and caravans. Heavy damage to crops and other vegetation. Small boats break moorings. Risk of power failure. Wind speeds between 125 km/h and 169 km/h.

Some damage to roofs and building structures. Some caravans destroyed. High risk of power failure. Wind speeds between 170 km/h and 224 km/h.

Heavy damage to roofs and building structures. Caravans destroyed and blown away. Risk of damage from flying debris. Widespread power failures. Wind speeds between 225km/h and 279 km/h.

Very heavy and widespread destruction. Wind speeds over 280 km/



Wind speed


Little damage – houses and buildings

Some damage – crops and vegetation

125 km/hr






Copy and complete table to


the five categories of tropical cyclones




In Australia, the Bureau of Meteorology identifies potentially dangerous cyclones and tracks them using weather stations on small islands and information from satellite pictures.

If a cyclone is deemed dangerous, a

cyclone warning

is issued in areas that might be affected from three

Tropical Cyclone Warning

Centres (TCWC) located in Brisbane, Darwin and Perth. Cyclone warnings tell people how to prepare for the coming storm. This can range from securing loose objects that might cause damage to evacuating the area until the storm has passed.People living in areas prone to tropical cyclones have to take precautions at all times. Citizens are encouraged to pack emergency kits and evacuation kits to keep in their houses. Houses in at-risk areas are built to strict building codes.


Go to


- The Emergency Management Australia website

Report on the most recent tropical cyclone that has been responded to.


Steps to take when planning for the cyclone season

Check the building regulations.

In some areas, if you are building a house, there are strict regulations that need to be followed. These can be found at your local council.  

Ensure your home is in good condition

, especially the roof: no loose tiles, the structure is secure and safe  

Clear property of loose items

and /or secure them. This reduces flying debris, which can cause fatal accidents  

Locate nearby safety. Find where your nearest safe higher ground is in case of flood warnings  Create your emergency survival kit and stock tinned food, water containers, medicines, important documents, torches, candles and matches, portable radio  Discuss with your family your emergency plan. Decide on the safest places in the house should a cyclone threaten, as well as ensuring that the emergency kit is easily accessible to all family members, a list of emergency contacts are clearly visible and a copy is in the emergency kit.


Emergency survival kit


Refer to the information and template in



emergency pantry list.

Plan the food for your family in an emergency.


Steps to take during and after a cyclone

During the cyclone, ensure you:

stay inside and be sheltered in the strongest part of the house (e.g. bathroom)

protect yourself with mattresses and blankets

hold firmly to a strong fixture such as pipes or stay under a solid table

remain indoors until the cyclone has completely passed. Remember in the eye of the cyclone there is a brief moment period of calm weather. After that, the cyclone will continue.

The calm after the storm

Remain indoors until you are advised that it is safe. When you do go outside, be aware of debris, buildings and trees may be unstable and power lines may have fallen.If you are driving, use recommended routes to avoid accidents, flooding of rivers and roads, and debris falling in the path of the cyclone.Activity:

Use word art to develop a pamphlet to educate individuals in cyclone prone areas on the steps to take to prepare for cyclones, during a cyclone and after the cyclone.


Social impacts

loss of lives and death

financial trauma because of loss of homes and people become worried that another cyclone will come and do further damage.

loss of food supplies can lead to malnutrition.

water contamination could occur and peoples health may be affected.

people come together and work as a team and community spirit can be strengthened.


Environmental impacts

Water supplies may be compromised if supplies are contaminated and pipelines cut.

Sewerage lines may be cut, resulting in a lack of sanitation, and poisons therefore leaching out into the environment.

If the cyclone brings flooding, there are the usual problems resulting from too much water, e.g. loss of animal and plant habitats.

Trees may be uprooted, and animal habitats destroyed. This causes the food chain to be broken, and it can be many months before food chain order is reestablished among the various species.

Beaches are often strewn with dead marine or coastal-dwelling creatures.

Litter ends up in the ocean, destroying animals' habitats.

Many coral reefs, fish and animals can be damaged and can take years to recover.


Economic impacts

Less income from exports and general economic turndown.

Flooding and high winds can destroy all crops.

Cost of creating a new infrastructure.

Not as many tourists ( short term effect)

Businesses closed down and people unemployed.


Develop a collage of the social, environmental and economic impacts of a cyclone in Australia.


Cyclone Tracy

Literacy Activity

When did cyclone Tracy hit Darwin?

What role did the local police and community leaders play in responding to the hazard?

What is the National Disaster Organisation and why did it become involved in the response to Cyclone Tracy?

Why do you think evacuation of Darwin was an essential response to Cyclone Tracy?

Calculate the percentage of Darwin’s population that was evacuated in the week following Cyclone Tracy.

How has cyclone Tracy better enabled communities to prepare for this type of hazard?


Comparison of recent Tropical Cyclones

- Activity

Go to site



Use this page to complete the following table:


CategoryLocationStorm Surge









Australian Government response to disasters

The primary role for protecting the community and property rests with state and territory governments.

The Australian Government supports the states and territories in recovery response through the provision of a range of programs and tailored assistance measures.

In November 2005, the Australian Government Disaster Recovery Committee (AGDRC) was established to provide advice on, and coordinate implementation of, tailored disaster recovery assistance measures to Australian individuals, families and communities in response to disasters.

It ensures that coordinated whole-of-Australian Government recovery assistance can be provided quickly to Australians.

It develops and coordinates whole-of-Australian Government social and community recovery packages.


20 March 2006 – Far North Queensland - Tropical cyclone Larry – Australian Government Response

A natural disaster zone was declared by the Queensland Government.

Ex-gratia payments

of $1,000 per eligible adult and $400 per eligible child for people whose principal place of residence was destroyed by the cyclone or was rendered uninhabitable

tax relief

to taxpayers who suffered damage to their homes and businesses.

a one-off income support program

for affected farmers and small business a tax-free grant of $25,000 for businesses demonstrating significant losses a wage subsidy for employers (businesses, farmers and non-profit organisations

) to help employers retain their pre-cyclone


levels and get back into production and business as quickly as possible

concessional loans of up to $500,000

to eligible farmers and business to re-establish their enterprises

assistance with excise on diesel or petrol fuel

used by businesses, farmers and households to generate their own electricity until normal services were restored

assistance for costs associated with hiring a generator

where electricity was needed to operate equipment required to relieve livestock distress.

Activity 2 - Role of groups – Describe how the Red Cross responded to Cyclone Larry. Go to


Activity 1 :

Use a table to


how the Queensland Government responded to cyclone Larry.




Go to


. Find PDF - St


Abergowrie College Cyclone Yasi: A Diary.Use this PDF to help you image you were one of the children at St Terersa’s. Write a diary entry describing what happened during your day.Develop a poster for a local school in Queensland to explain how individuals could help Cyclone Yasi victims.