Cyclone CATEGORIES
Cyclone Severity Categories
An estimate of cyclone severity is now included in all tropical
cyclone advices.
Categories of cyclone severity range from " 1 "
for weak cyclones to "5" for the most severe cyclones.
Accordingly, the risk of property and crop damage,
shore erosion and danger to life increases from low for a category 1
to very high for a category 5 cyclone.
Using this severity scale, communities will be
able to assess the degree of cyclone threat and take appropriate
action.
It must be emphasized that the category refers to
the severity in the zone of maximum winds and therefore the effects
felt at individual locations may not be exactly as described in the
accompanying table.
Damage will vary from location to location depending upon factors such
as:
- how far you are from the zone of maximum winds
- how exposed the location is
- building standards
- vegetation type
- resultant flooding
It should also be noted that the category does not refer to storm
tides; if a storm tide is expected it will be mentioned separately in
the cyclone warning.
Categories Comparison
Category 1
Strongest gust less than 125 km/h
Typical effects (indicative only) - Negligible house damage. Damage to
some crops, trees and caravans. Craft may drag moorings.
Category 2
Strongest gust 125 - 170 km/h
Typical effects (indicative only) - Minor house damage. Significant
damage to signs, trees and caravans. Heavy damage to some crops. Risk
of power failure. Small craft may break moorings.
Category 3 (e.g. Winifred)
Strongest gust 170 - 225 km/h
Typical effects (indicative only) - Some roof and structural damage.
Some caravans destroyed. Power failure likely.
Category 4 (e.g. Tracy)
Strongest gust 225 - 280 km/h
Typical effects (indicative only) - Significant roofing loss and
structural damage. Many caravans destroyed and blown away. Dangerous
airborne debris. Widespread power failure.
Category 5 (e.g. Orson)
Strongest gust More than 280 km/h
Typical effects (indicative only) - Extremely dangerous with
widespread destruction.
For more information on Cyclones visit
www.bom.gov.au
CAIRNS & REGIONAL CYCLONES -
AUSTRALIA
Cairns - Port Douglas - Great Barrier Reef Australia.
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