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Floods in WA
In WA, flooding could happen anywhere, at any time and from a variety of water sources including rivers and creeks, storm tides, overflowing catchments and due to heavy rainfall caused by cyclones. Apart from the physical damage to property, experiencing a flood can be an extremely emotional time.
When do floods occur?
Many devastating floods have occurred in Australia. Your local area may have been affected by flood. Flooding occurs most commonly from heavy rainfall when natural watercourses do not have the capacity to convey excess water. They can also arise after a cyclone, where low lying coastal areas may flood due to storm surge from the ocean and heavy rain.
However, floods are not always caused by heavy rainfall. They can result from other phenomenon, particularly in coastal areas where inundation can be caused by a storm surge associated with a tropical cyclone, a tsunami or a high tide coinciding with higher than normal river levels. Dam failure, triggered for example by an earthquake, will result in flooding of the downstream area, even in dry weather conditions.
Major flooding in Karratha and Dampier is typically associated with storm surge. Flooding was a feature of historical cyclone events affecting Roebourne on the Harding River. However, the construction of the Harding River Dam, some 20km upstream of the town in 1983–84 has eased the flood threat to the town. (Source: Bureau of Meteorology)
During a flood you may become stranded for many days until the water subsides and some remote areas can be isolated for months by floods. If your home is near a waterway or on low-lying land it could be flooded, even if you have never seen floodwaters there. It does not have to be raining in your area for flooding to occur.
The impact of floods
Every year in Australia, floods cause millions of dollars damage to buildings and critical infrastructure, such as roads and railways as well as to agricultural land and crops. They also disrupt business and can affect the health of communities. Between 1967 and 2005, the average direct annual cost of flooding has been estimated at A$377 million. (Source: Geoscience Australia)
A timeline of major floods and cyclones in WA:
- Cyclone Paul, North WA. April 2000
- Cyclone George, North WA. March 2000
- Perth, Jan 2000
- Cyclone Vance, Exmouth. March 1999
- Moora. March 1999
- Cyclone Olivia, Pannawonica. April 1996
- Cyclone Bobby, Kalgoorlie. February 1995
- Perth Flood. Jan 1992
- Cyclone Herbie, Carnarvon to Denham. May 1988
- East Perth. July 1987
- Cyclone Dean, Pilbara. February 1980
- Cyclone Amy, Port Hedland. January 1980
- Cyclone Hazel, Kimberley and Pilbara Coast. March 1979
- Cyclone Alby, Perth. April 1978
- Cyclone Thelma, Port Hedland. December 1975
Did you know?
Whim Creek, in the Pilbara, received 747mm of rain in one day on 3 April 1898. Reportedly caused by a willy willy, this is the highest daily rainfall recorded for WA since records began.