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Natural Hazards
Year 9 Geography
5A1 Investigating Australia’s Physical Environments
Syllabus Agenda
the nature of the natural hazard in Australia
the geographical processes involved
the impacts of the natural hazard:
economic
Environmental
social
the 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
hazard.
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.
Activity
Using http://edu.glogster.com
Create a glog on natural hazards.
Include a definition and an
illustration 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
Activity
Using figure 2.4
a) Name the three
most costly
natural hazards in
terms of building
damage in
Australia
Cyclones
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
Australia
Tropical Cyclones 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.
(a) Activity
Go to http://www.studyismybuddy.com
Download the Cyclone worksheet
Complete the worksheet using the
http://www.ema.gov.au/www/ema/schools.nsf/Page/
Get_The_FactsCyclones website
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 tropical 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 air to rise further into the atmosphere.
If the air pressure in the upper atmosphere is high, then the rising column of warm
air will spiral outwards in the upper atmosphere and air will 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
o
Little damage to houses and other buildings. Some damage to crops and other
vegetation. Wind speeds less than 125 km/h.
o
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.
o
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.
o
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.
o
Very heavy and widespread destruction. Wind speeds over 280 km/
Category
1
2
3
4
5
Damage
Wind speed
Little damage – houses and buildings
Some damage – crops and vegetation
125 km/hr
Activity:
Copy and
complete table
to summarise
the five
categories of
tropical cyclones
Cyclone defences
ACTIVITY
Go to www.ema.gov.au - The Emergency
Management Australia website
Report on the most recent tropical cyclone
that has been responded to.
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.
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
ACTIVITY
Refer to the
information
and template
in Edmodo
called
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
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.
Activity
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
http://www.abc.net.au/news/infographics/cycloneseason-2010-2011/comparison.htm.
Use this page to complete the following table:
Cyclone
YASI
LARRY
TRACY
Category
Location
Storm Surge
Rainfall
Wind
Damage
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-ofAustralian Government recovery assistance
can be provided quickly to Australians.
It develops and coordinates whole-ofAustralian Government social and community
recovery packages.
Australian
Government
response to
disasters
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
20 March 2006 –
Far North
Queensland Tropical cyclone
Larry – Australian
Government
Response
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 labour 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 1 :
Use a table to
summarise
how the
Queensland
Government
responded to
cyclone Larry.
Activity 2 - Role of groups – Describe how the Red Cross responded to Cyclone Larry. Go to
http://www.redcross.org.au/ourservices_acrossaustralia_disasteremergencyservices_larry2006.htm
Cyclone Yasi
Go to Edmodo. Find PDF - St Terersa’s 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.