How Cyclone Larry
formed
By Ashleigh Campbell
Firstly, what is a cyclone?
• As found in the Oxford Dictionary, a cyclone is
a large-scale, atmospheric wind and pressure
system characterized by low pressure at its
centre and by circular wind motion, counter
clockwise in the Northern Hemisphere,
clockwise in the Southern Hemisphere. They
only form over warm waters in the tropical
areas of the oceans where the sea
temperatures are 26.5°C or greater.
How are cyclones caused?
• Cyclones are caused by the warm air that lies
over open waters. It is heated by the sun and
rises very quickly, creating points with low air
pressure.
• That warm air becomes transformed into
moisture which is absorbed by thunderclouds.
• Cool air rushes to fill the empty spaces left by
the warm air.
How are cyclones caused? (continued)
• Because of the continuous turning of the
Earth on its axis, the air is bent inwards and
begins to rotate upwards with great force.
• The spiraling winds start to turn faster and
faster and thus forms a massive circle of winds
which can have a diameter of up to 2000
kilometers.
• Winds created by the cyclone can reach
speeds of 200km/h
How did Cyclone Larry form?
• The Tropical Cyclone Larry started as a low pressure system
over the eastern Coral Sea. It formed into a tropical cyclone
in the early hours of 18th May, and proceeded on a westerly
track towards the Queensland coast.
• Larry became a severe tropical cyclone at 10am on the 18th
and continued to intensify as it approached the
Queensland coast, reaching Category 4 early on the 19th.
• The eye of Larry crossed the coast near Innisfail between
6:20am and 7:20am on the 20th March. Larry started to
weaken after it hit landfall but maintained cyclone strength
for several hundred kilometres inland until the early hours
of the 21st. Cyclone Larry moved into western Queensland
to the north of Mount Isa.