Cyclones
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Every cyclone has an ‘eye’
A cyclone is a low pressure system that forms over
warm tropical waters. It can have wind gusts of up to
280 kilometres per hour around a calm centre.
The eye is in the centre of the cyclone and can vary in size from
10 km to 100 km, depending on the severity of the storm. Because
there is the least amount of air pressure in the eye, it produces
clear weather with light wind, no clouds, no rain and some
sunshine. Do not be fooled by the eye: the storm is not over yet.
This is only the middle of the storm. Depending on the wind gusts,
the eye may pass in a few minutes or it may take several hours.
Did you know?
>The average life of a cyclone is one week.
>After the eye passes and the other side of the cyclone hits, the
wind blows with equal strength but in the opposite direction.
>Tropical cyclones from the Southern Hemisphere spin
About Cyclones
Tropical Cyclones are formed over the ocean in the area around the
equator, between the Tropic of Cancer and the Tropic of Capricorn.
clockwise, while hurricanes and typhoons in the Northern
Hemisphere spin anti-clockwise.
>Cyclone Tracy was Australia’s most destructive cyclone.
>Cyclones are assigned names, which are chosen from a list.
Cyclones
Cyclones are giant, spinning, whirlwind storms. They are called
hurricanes in North America and typhoons in Asia. In order for a
cyclone to be identified as a cyclone, it must be travelling over 119
km per hour and it must have been formed over the ocean in a
tropical region. These great storms are usually dangerous and can
cause damage to everything in their path. A cyclone will often bring
with it heavy rains that can cause flooding.
In order for a cyclone to form, the ocean waters need to be warm,
at least 26°C. Above the warm ocean, water evaporates and forms
clouds. If there is low air pressure where the clouds are formed,
it pulls them in and they begin to rotate. It is the earth rotating
and spinning on its axis that causes the cyclone’s clouds to rotate.
Clouds will continue to form and begin spinning more.
Once a cyclone arrives over land, its strength weakens and it
begins to fade out.
How often do they occur?
Cyclone season in Australia is between November and April,
however cyclones can still occur in May. The season for hurricanes
and typhoons in the Northern Hemisphere is between June and
November.
Names of cyclones
The name of each cyclone is taken from a list of approximately
104 names that are used only for cyclones in the Australian Region.
If a cyclone begins and is named in another region, it will keep that
name when it enters Australia’s zone of responsibility. The names
are usually chosen in sequence, returning to the beginning when
the end of the list is reached. Names alternate between male and
female and if a cyclone has a significant effect in the Australian
Region (such as Cyclone Tracy) the name will be removed from the
list as a mark of respect.
Source
https://schools.aemi.edu.au
According to the Bureau of Meteorology, Australia has, on average,
13 cyclones a year.
Categories and severity
Cyclones are categorised according to their strength. There are
five categories: Category 1 is the weakest and Category 5 is the
strongest.
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Cyclones
S t u d e nt
A c t i v it i e s
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Research #1
Research how many cyclones there have been in Australia over
the last 50 years.
Show on a map where they struck and their strength.
Report to the class about one cyclone, including human and nonhuman damage.
Research #2
Research one cyclone from another country (not Australia) in
the last 50 years (remember that you may have to research on
hurricanes or typhoons).
Write a newspaper article reporting on one of these cyclones,
including human and non-human damage.
Research #3
Search for 10 interesting facts about one of the major cyclones
in the world.
In a group, make a table of how many lives were lost in each
of these major cyclones.
Investigate if cyclones are more likely to occur in some areas than
others – explain the reasons why.
Research #4
Learn about the 2015 Vanuatu Cyclone. Find out about areas most
affected. How is the recovery process today? Draw a web map of
the ways that the cyclone impacted the poor people in Vanuatu.
Link
Follow these links to learn more.
>https://disastermapper.ema.edu.au/#/intro
>http://scienceweb.asta.edu.au/years-5-6/unit3/lesson-three/yr56unit3-lesson-three.html
Poster
Imagine you are training people what to do when a cyclone comes.
Make a poster to give them some ideas.
Aid Organisations
If you were part of an aid organisation (like Australian Lutheran
World Service) what things do you think would need to be done to
respond to a disaster like a cyclone? Make a list. Which responses
are most urgent? What kinds of things need to happen one week,
one month, one year after a cyclone?
w/ www.alws.org.au e/ [email protected] t/ 1300 763 407