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Cyclones often
produce winds in excess of 200 km/h which can cause extensive
damage to property and turn debris into dangerous missiles.
 Cyclones
can also bring flooding rains, which cause further damage to property,
and increase the risk of drowning.
Cyclones can
cause huge seas, putting vessels in danger both in harbour and
out at sea.
Most deaths
from cyclones occur as a result of drowning, collapsed buildings,
or flying debris which becomes lethal in high winds.
Above:
Cyclone Justin crosses Cairns. 1
What
is a cyclone?
Tropical cyclones
(also known as hurricanes in North America and typhoons in Asia)
are giant whirlwinds of air and dense cloud spiraling at over
120 km/hr around a central 'eye' of extreme low pressure.
 Australia's
cyclone season is usually from December to April and affects most
of the Queensland coast. The greatest threat lies north of the
Tropic of Capricorn.
When a tropical
depression develops and its associated winds reach gale force,
it will be classified as a tropical cyclone and will be given
a name.
Cyclones occur
frequently in the Southern Hemisphere with an average of 10 cyclones
per year tracked by the Bureau of Meteorology in the Australian
region.
The 'life-cycle'
of the average tropical cyclone is about seven days, but can extend
to over three weeks.
Above
right:
Cyclone Rona devastates North Queensland pub in 1999. 2
Cyclone
watch
A cyclone
watch is issued by the Bureau of Meteorology when a cyclone or
developing cyclone is likely to affect coastal or inland communities
within 24 to 48 hours.
A cyclone
watch will include an estimate of the cyclone's position, its
intensity, severity and movement.
Cyclone watches will be issued every three hours initially and
hourly once the cyclone nears the coast.
Cyclone
warnings
A cyclone
warning is issued by the Bureau of Meteorology when a cyclone
or developing cyclone is likely to affect coastal or inland communities
within 24 hours.
Warnings will
identify the communities likely to be affected, the name of the
cyclone, its position, intensity, severity and movement.
Communities
under threat will be advised to take certain precautions to safeguard
life and property.
Cyclone
categories
Category 1
- wind gusts less than 125 km/hr
Category 2 - wind gusts 125 to 169 km/hr
Category 3 - wind gusts 170 to 224 km/hr
Category 4 - wind gusts 225 to 279 km/hr
Category 5 - wind gusts more than 280 km/hr
1. Photo courtesy
of Courier Mail
2. Photo courtesy
of Cairns Post
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