2010 Gascoyne River flood
Encyclopedia
The December 2010 Gascoyne River flood was regarded as the most severe flood to take place along the Gascoyne River
in Western Australia
on record. Triggered by record-breaking rainfall, amounting to over 6,000 percent of the monthly mean, 313.6 mm (12.3 in) and 5 mm (0.196850393700787 in) respectively, in just four days, the floods caused widespread damage in the region. By 17 December, the river began to rise in response to the heavy rains, eventually exceeding its banks within two days. Water levels reached record values at three stations along the river, cresting at 15.53 m (51 ft) near Fishy Pool. Evacuation orders were issued for several towns affected by rising waters. The most substantial impact was felt in Carnarvon
where entire homes were washed away. Following the disaster, emergency supplies and funds were distributed to affected residents to aid them in restoring their livelihoods. Though no people died in the event, an estimated two thousand head of cattle
perished and damage was estimated at A$100 million.
developed northwest of Western Australia
. Slowly tracking to the south, the system spawned an low pressure system
(2010–11 Australian cyclone - Tropical Low 03U) by 15 December. Turning southeastward, the low later made landfall
near Coral Bay
on 18 December. Within hours of moving inland, the system turned to the southwest and moved back over water the following morning. The storm was last noted on 20 December well off the coast of Western Australia.
Climatologically, the region affected by the floods is a dry area, with annual rainfall in most areas averaging between 200 millimetre. December is regarded as the third-driest month of the year, with a mean rainfall of just 5 mm (0.196850393700787 in). Prior to the event, much of the Gascoyne River catchment was suffering from a drought
and many places abruptly shifted from drought conditions to record floods in less than 24 hours. Additionally, the river had no water flow before the floods, being a dry riverbed.
Between 16 and 20 December, the low produced heavy rains over much of the area around Shark Bay
. These rains reached record amounts in numerous locations and greatly surpassed the monthly mean December rainfall; some areas reached levels of more than 6,000 percent above this value due to the storm. During a 24 hour span on 17 December, a record-shattering 247.6 mm (9.7 in) of rain fell in Carnarvon
. This value greatly exceeded both the previous record of 119.4 mm (4.7 in), set in 1923, and the city's annual average of 228.8 mm (9 in). Several other locations recorded similar rainfall in the region, also surpassing their annual rainfall totals in under two days. During the five day span in which there was rainfall, a maximum of 313.6 mm (12.3 in) was measured in Carnarvon. A total of 23 towns and cities recorded record 24 hour rainfall for the month of December in relation to the storm. According to the Bureau of Meteorology, Carnarvon Airport
measured its wettest month on record, with 255 mm (10 in) of rain falling in just four days. The previous record was set in June 1895 at 219.7 mm (8.6 in).
Prior to the arrival of the monsoon low, the Bureau of Meteorology issued a flood watch
for the Gascoyne River catchment on 15 December, stating that 150 to 200 mm (5.9 to 7.9 in) of rain could fall over the following 72 hours. This was later upgraded to a flood warning
as the situation worsened on 18 December. Once the rains ceased on 21 December, the warning was discontinued. During the torrential downpours, the Gascoyne River began to rise on 17 December, threatening to flood several towns and cities along its banks. Water levels continuously rose through the morning of 19 December, at which time the floods attained their peak. In Fishy Pool, the river reached a record crest of 15.53 m (51 ft), surpassing the previous peak of 12.23 m (40.1 ft) in 1980. The floods subsided relatively quickly as the river dropped below flood stage on 21 December.
Once the river overflowed its banks, flood waters spread through vast agricultural and grazing areas, severely damaging crops and killing an estimated two thousand head of cattle. By 19 December, evacuations had taken place in rural parts of Carnarvon, with 200 residents residing in emergency shelters. The entire city was isolated from surrounding areas as flood waters cut off all roads; however, the downtown centre of the city remained untouched due to levee
s that were constructed in 1960. On person had to be rescued by a police helicopter after he was swept away by strong currents. Large portions of the North West Coastal Highway
were shut down due to flooding for several days, hindering travel in the region. In Yalgoo
, six residents required an airlift after becoming stranded in their home. A total of 30 people were rescued by helicopter on 20 December in Gascoyne Junction
. Two days later, the entire town was evacuated and displaced residents sought refuge in Carnarvon. The most severe losses took place in rural parts of Carnarvon, such as Gascoyne Junction, where several homesteads were washed away in the floods. Entire plantations were washed away by the floods and the center of Gascoyne Junction was referred to as an, "obliterated ghost town." Additionally, one person stated that he lost 50 percent of his banana crop. Throughout the affected area, preliminary assessments placed damage at A$100 million.
stated that he did not want to place blame on any agency, though hoped for improvement during the future. More than 100 local government areas and regions were declared natural disaster areas on 21 December, encompassing areas from central Western Australia to the Pilbara coastline.
By January 2011, much of the nation's attention had shifted from the Gascoyne flood to the devastating floods in Queensland
. Many residents struggling to get their lives back together were frustrated with the government and demanded aid. Though people affected by the floods were to be given A$15,000 in funds, they expressed further anger after hearing that residents in Queensland would receive A$25,000. On 11 January, Prime Minister Julia Gillard
stated that the imbalance in funds was to be corrected and residents of Western Australia would receive equal amounts to those in Queensland. By 20 January, donations for flood victims from the Lord Mayor's Distress Relief Fund exceeded A$1 million. Power restoration, especially in Gascoyne Junction, was unusually sluggish. Dozens of residents were without power for eight weeks, as electricity was finally restored between 12 and 13 February. This coincided with the arrival of replacement furniture from Paraburdoo
; however, heavy rains renewed flooding and prevented most residents from picking up the supplies.
Gascoyne River
At 760 km, the Gascoyne River is the longest river in Western Australia.The river rises below Wilgoona Hill in the Robinson Ranges west of the Gibson Desert and it flows into Shark Bay and the Indian Ocean at Carnarvon....
in Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
on record. Triggered by record-breaking rainfall, amounting to over 6,000 percent of the monthly mean, 313.6 mm (12.3 in) and 5 mm (0.196850393700787 in) respectively, in just four days, the floods caused widespread damage in the region. By 17 December, the river began to rise in response to the heavy rains, eventually exceeding its banks within two days. Water levels reached record values at three stations along the river, cresting at 15.53 m (51 ft) near Fishy Pool. Evacuation orders were issued for several towns affected by rising waters. The most substantial impact was felt in Carnarvon
Carnarvon, Western Australia
Carnarvon is a coastal town situated approximately 900 kilometres north of Perth, Western Australia. It lies at the mouth of the Gascoyne River on the Indian Ocean. The popular Shark Bay world heritage area lies to the south of the town and the Ningaloo Reef lies to the north...
where entire homes were washed away. Following the disaster, emergency supplies and funds were distributed to affected residents to aid them in restoring their livelihoods. Though no people died in the event, an estimated two thousand head of cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
perished and damage was estimated at A$100 million.
Background
On 11 December 2010, a monsoon troughMonsoon trough
The monsoon trough is that portion of the Intertropical Convergence Zone which extends into or through a monsoon circulation, as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and...
developed northwest of Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
. Slowly tracking to the south, the system spawned an low pressure system
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
(2010–11 Australian cyclone - Tropical Low 03U) by 15 December. Turning southeastward, the low later made landfall
Landfall (meteorology)
Landfall is the event of a tropical cyclone or a waterspout coming onto land after being over water. When a waterspout makes landfall it is reclassified as a tornado, which can then cause damage inland...
near Coral Bay
Coral Bay, Western Australia
Coral Bay is a small town on the coast of Western Australia, 1,200 km north of Perth. It exists primarily for tourism, with a side industry of fishing...
on 18 December. Within hours of moving inland, the system turned to the southwest and moved back over water the following morning. The storm was last noted on 20 December well off the coast of Western Australia.
Climatologically, the region affected by the floods is a dry area, with annual rainfall in most areas averaging between 200 millimetre. December is regarded as the third-driest month of the year, with a mean rainfall of just 5 mm (0.196850393700787 in). Prior to the event, much of the Gascoyne River catchment was suffering from a drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
and many places abruptly shifted from drought conditions to record floods in less than 24 hours. Additionally, the river had no water flow before the floods, being a dry riverbed.
Between 16 and 20 December, the low produced heavy rains over much of the area around Shark Bay
Shark Bay
Shark Bay is a World Heritage listed bay in Western Australia. The term may also refer to:* the locality of Shark Bay, now known as Denham* Shark Bay Marine Park* Shark Bay , a shark exhibit at Sea World, Gold Coast, Australia* Shire of Shark Bay...
. These rains reached record amounts in numerous locations and greatly surpassed the monthly mean December rainfall; some areas reached levels of more than 6,000 percent above this value due to the storm. During a 24 hour span on 17 December, a record-shattering 247.6 mm (9.7 in) of rain fell in Carnarvon
Carnarvon, Western Australia
Carnarvon is a coastal town situated approximately 900 kilometres north of Perth, Western Australia. It lies at the mouth of the Gascoyne River on the Indian Ocean. The popular Shark Bay world heritage area lies to the south of the town and the Ningaloo Reef lies to the north...
. This value greatly exceeded both the previous record of 119.4 mm (4.7 in), set in 1923, and the city's annual average of 228.8 mm (9 in). Several other locations recorded similar rainfall in the region, also surpassing their annual rainfall totals in under two days. During the five day span in which there was rainfall, a maximum of 313.6 mm (12.3 in) was measured in Carnarvon. A total of 23 towns and cities recorded record 24 hour rainfall for the month of December in relation to the storm. According to the Bureau of Meteorology, Carnarvon Airport
Carnarvon Airport
Carnarvon Airport is an airport at Carnarvon, Western Australia.-Airlines and destinations:...
measured its wettest month on record, with 255 mm (10 in) of rain falling in just four days. The previous record was set in June 1895 at 219.7 mm (8.6 in).
Impact
| Location | Rainfall | Average rainfall | |
|---|---|---|---|
| December | Annual | ||
| Carnarvon Carnarvon, Western Australia Carnarvon is a coastal town situated approximately 900 kilometres north of Perth, Western Australia. It lies at the mouth of the Gascoyne River on the Indian Ocean. The popular Shark Bay world heritage area lies to the south of the town and the Ningaloo Reef lies to the north... |
313.6 mm (12.3 in) | 5.7 mm (0.224409448818898 in) | 228.8 mm (9 in) |
| Marron | 277.6 mm (10.9 in) | 7 mm (0.275590551181102 in) | 206.8 mm (8.1 in) |
| Doorawarrah | 259.8 mm (10.2 in) | 7.7 mm (0.303149606299213 in) | 231.8 mm (9.1 in) |
| Mount Narryer | 248 mm (9.8 in) | 7.1 mm (0.279527559055118 in) | 196 mm (7.7 in) |
| Carey Downs | 244 mm (9.6 in) | 9.7 mm (0.381889763779528 in) | 206.2 mm (8.1 in) |
| Winderie | 208 mm (8.2 in) | 6.6 mm (0.259842519685039 in) | 230.2 mm (9.1 in) |
Prior to the arrival of the monsoon low, the Bureau of Meteorology issued a flood watch
Flood watch
Flood alerts are issued by weather agencies to alert residents that flood conditions are a possibility for their area.-Types of flood alerts:...
for the Gascoyne River catchment on 15 December, stating that 150 to 200 mm (5.9 to 7.9 in) of rain could fall over the following 72 hours. This was later upgraded to a flood warning
Flood warning
Flood warning is closely linked to the task of flood forecasting. The distinction between the two is that the outcome of flood forecasting is a set of forecast time-profiles of channel flows or river levels at various locations, while "flood warning" is the task of making use of these forecasts to...
as the situation worsened on 18 December. Once the rains ceased on 21 December, the warning was discontinued. During the torrential downpours, the Gascoyne River began to rise on 17 December, threatening to flood several towns and cities along its banks. Water levels continuously rose through the morning of 19 December, at which time the floods attained their peak. In Fishy Pool, the river reached a record crest of 15.53 m (51 ft), surpassing the previous peak of 12.23 m (40.1 ft) in 1980. The floods subsided relatively quickly as the river dropped below flood stage on 21 December.
Once the river overflowed its banks, flood waters spread through vast agricultural and grazing areas, severely damaging crops and killing an estimated two thousand head of cattle. By 19 December, evacuations had taken place in rural parts of Carnarvon, with 200 residents residing in emergency shelters. The entire city was isolated from surrounding areas as flood waters cut off all roads; however, the downtown centre of the city remained untouched due to levee
Levee
A levee, levée, dike , embankment, floodbank or stopbank is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels...
s that were constructed in 1960. On person had to be rescued by a police helicopter after he was swept away by strong currents. Large portions of the North West Coastal Highway
North West Coastal Highway
North West Coastal Highway in Western Australia is a generally north-south Western Australian highway which links the fishing town of Geraldton with the iron ore port of Port Hedland. It is long, and constructed as a sealed 2-lane single carriageway with overtaking lanes in some parts. It was...
were shut down due to flooding for several days, hindering travel in the region. In Yalgoo
Yalgoo, Western Australia
-Further reading:* Palmer, Alex. Yalgoo Fremantle, W.A: Lap Industries. ISBN 0959058400- See also :* Yalgoo - the ecological region* Thundelarra* Shire of Yalgoo - the local government region...
, six residents required an airlift after becoming stranded in their home. A total of 30 people were rescued by helicopter on 20 December in Gascoyne Junction
Gascoyne Junction, Western Australia
Gascoyne Junction is a small town in the Gascoyne region of Western Australia, inland from Carnarvon on the junction of the Gascoyne River and Lyons River. At the 2006 census, Gascoyne Junction had a population of 149.-History:...
. Two days later, the entire town was evacuated and displaced residents sought refuge in Carnarvon. The most severe losses took place in rural parts of Carnarvon, such as Gascoyne Junction, where several homesteads were washed away in the floods. Entire plantations were washed away by the floods and the center of Gascoyne Junction was referred to as an, "obliterated ghost town." Additionally, one person stated that he lost 50 percent of his banana crop. Throughout the affected area, preliminary assessments placed damage at A$100 million.
Response
By 20 December, arrangements for the delivery of emergency food and water supplies were made and expected to reach Carnarvon later that day. Supplies were also sent to outlying Aboriginal communities affected by the floods. After evacuating on 20 December, residents were allowed to return to their homes two days later in Carnarvon. However, most were left without power and clean water and required assistance from local agencies. Following the disaster, there were concerns that the Australian government could have prevented at least some of the floods by following through with a flood mitigation program. Dudley Maslen, the President of The Shire of CarnarvonShire of Carnarvon
The Shire of Carnarvon is a Local Government Area in the Gascoyne region of Western Australia, located about north of the state capital, Perth. The Shire covers an area of , and its seat of government is the town of Carnarvon...
stated that he did not want to place blame on any agency, though hoped for improvement during the future. More than 100 local government areas and regions were declared natural disaster areas on 21 December, encompassing areas from central Western Australia to the Pilbara coastline.
By January 2011, much of the nation's attention had shifted from the Gascoyne flood to the devastating floods in Queensland
2010–2011 Queensland floods
A series of floods hit Australia, beginning in December 2010, primarily in the state of Queensland including its capital city, Brisbane. The floods forced the evacuation of thousands of people from towns and cities. At least seventy towns and over 200,000 people were affected. Damage initially was...
. Many residents struggling to get their lives back together were frustrated with the government and demanded aid. Though people affected by the floods were to be given A$15,000 in funds, they expressed further anger after hearing that residents in Queensland would receive A$25,000. On 11 January, Prime Minister Julia Gillard
Julia Gillard
Julia Eileen Gillard is the 27th and current Prime Minister of Australia, in office since June 2010.Gillard was born in Barry, Vale of Glamorgan, Wales and migrated with her family to Adelaide, Australia in 1966, attending Mitcham Demonstration School and Unley High School. In 1982 Gillard moved...
stated that the imbalance in funds was to be corrected and residents of Western Australia would receive equal amounts to those in Queensland. By 20 January, donations for flood victims from the Lord Mayor's Distress Relief Fund exceeded A$1 million. Power restoration, especially in Gascoyne Junction, was unusually sluggish. Dozens of residents were without power for eight weeks, as electricity was finally restored between 12 and 13 February. This coincided with the arrival of replacement furniture from Paraburdoo
Paraburdoo, Western Australia
Paraburdoo is a town in the Pilbara region of Western Australia. The name of the town comes from the Aboriginal word for 'white cockatoo'. It is located 1,536 kilometres north of Perth and 79 kilometres southwest of Tom Price. Paraburdoo was developed in the early 1970s to support Hamersley...
; however, heavy rains renewed flooding and prevented most residents from picking up the supplies.
See also
- 2010–11 Australian region cyclone season2010–11 Australian region cyclone seasonThe 2010–11 Australian region cyclone season was a near average tropical cyclone season, with eleven tropical cyclones forming compared to an average of 12. The season began on 1 November 2010 and ended on 30 April 2011. The Australian region is defined as being to south of the equator, between the...
- 2010-2011 Queensland floods - catastrophic flooding in QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
that began around the same time as the Gascoyne flood.