Year 6, unit 3
Weather extremes
Name: ........................................................... Class: ................... Date: .................
Lesson 4: Cyclone impact
Worksheet:
a.
The impact of cyclones – wind
The destructive winds associated with cyclones can cause extensive property
damage and turn flying debris into potentially lethal weapons. Trees can be flattened,
buildings and roads destroyed and other infrastructure such as signs and powerlines
can also be torn down by excessive wind.
The amount of damage caused by cyclonic winds is dependent on the maximum
speed of the wind gusts, how long these destructive winds last as well as the
variation in the direction of the wind.
The topography of the land can also play a part in the destructiveness of the wind.
Hills and mountains can provide shelter from the wind on the leeward side and
sometimes the terrain can increase the wind speed, such as when the wind moves
over the crests of hills.
How do cyclones impact on people and the environment?
How do cyclones cause rapid change to the Earth’s surface?
© 2013 Education Services Australia Ltd, except where indicated otherwise. You may copy, distribute
and adapt this material free of charge for non-commercial educational purposes, provided you retain
all copyright notices and acknowledgements.
Year 6, unit 3
Weather extremes
Name: ........................................................... Class: ................... Date: .................
b.
The impact of cyclones – rainfall
Cyclones bring heavy rainfall that can produce extensive flooding, particularly in lowlying areas. This can lead to further damage to property as homes and businesses
are flooded and roads are destroyed by floodwaters. It can also result in the death of
people through drowning.
The amount of damage caused by the heavy rain is affected by how long the heavy
rainfall lasts, the amount of moisture within the cyclone and the topography of the
land. If the cyclone hits land in low-lying areas then the amount of damage caused by
the rainfall can increase as the flood levels continue to rise.
Severe erosion may also occur. Areas of land become saturated with moisture,
topsoil can be washed away and creeks and riverbanks can be further eroded due to
the force of the water.
How do cyclones impact on people and the environment?
How do cyclones cause rapid change to the Earth’s surface?
© 2013 Education Services Australia Ltd, except where indicated otherwise. You may copy, distribute
and adapt this material free of charge for non-commercial educational purposes, provided you retain
all copyright notices and acknowledgements.
Year 6, unit 3
Weather extremes
Name: ........................................................... Class: ................... Date: .................
c. The impact of cyclones – storm surge
A storm surge is a surge of water that is usually two to five metres higher than the
normal tide level. It is caused by a combination of strong winds pushing the water
towards the shore, and the low pressure in the area in which a cyclone forms.
Surges vary in size due to the speed of the winds, the topography of the land, the
presence of coral reefs, the size and speed of the cyclone and the tidal flow at the
time.
Potentially dangerous surges occur along low-lying coastlines, and across inland
waterways such as rivers, lakes and estuaries. These areas can suffer from severe
flooding. The storm surge and the constant pounding nature of the waves can cause
serious damage to coastal structures such as jetties, rock walls, marinas and coastal
buildings. Storm surges can also cause severe coastal erosion as the waves erode
sand from beaches and dunes, weaken coastal cliffs and damage the shoreline. All
of this can dramatically change the existing shoreline.
How do cyclones impact on people and the environment?
How do cyclones cause rapid change to the Earth’s surface?
© 2013 Education Services Australia Ltd, except where indicated otherwise. You may copy, distribute
and adapt this material free of charge for non-commercial educational purposes, provided you retain
all copyright notices and acknowledgements.
Year 6, unit 3
Weather extremes
Name: ........................................................... Class: ................... Date: .................
d. The impact of cyclones – other damage
Strong cyclonic winds can cause damage to crops grown in the area. Entire crops,
plantations and areas of natural vegetation can be wiped out. This can result in
economic damage as these crops need to be replaced and the landowners lose any
profits that could have come from the sale of the crop. This also has implications for
people living thousands of kilometres away as the damaged crops, such as bananas,
are then in short supply, which can result in a price increase.
People and animals may be seriously injured or even lose their lives. Property
damage can occur and people and animals may be without shelter for many months.
Cyclones also have a large economic impact on a region. Businesses may need to
rebuild and people need to repair their homes and replace damaged property. The
surrounding infrastructure such as roads, power and food, and fresh water supplies
will also be affected and may take many months to repair or replace.
How do cyclones impact on people and the environment?
How do cyclones cause rapid change to the Earth’s surface?
© 2013 Education Services Australia Ltd, except where indicated otherwise. You may copy, distribute
and adapt this material free of charge for non-commercial educational purposes, provided you retain
all copyright notices and acknowledgements.