The 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, although the first tropical cyclone formed on 28 October. The Australian region is defined as being to south of the equator, between the 90th meridian east and 160th meridian east. Tropical cyclones in this area are monitored by five Tropical Cyclone Warning Centres (TCWC's): Jakarta, Port Moresby, Perth, Darwin, and Brisbane, each of which have the power to name a tropical cyclone. The TCWC's in Perth, Darwin, and Brisbane are run by the Bureau of Meteorology, who designate significant tropical lows with a number and the U suffix. The Joint Typhoon Warning Center also issues unofficial warnings for the region, designating significant tropical cyclones with the "S" suffix when they form west of 135°E, and the "P" suffix when they form east of 135°E.
Predictions of tropical cyclone activity
Actual activity (BoM)
Actual activity (JTWC)
Source:BoM's Seasonal Outlook for Tropical Cyclones.
Source:GCACIC's Seasonal outlook for tropical cyclones.
Bureau of Meteorology
Since the 2009–10 season, the Bureau of Meteorology's National Climate Centre (NCC), ahead of each season has issued a seasonal forecast for the whole basin between 90°E and 160°E. This season the NCC predicted how many tropical cyclones would pass through the basin as a whole as well as the Western, Northwest, Northern and Eastern regions with each prediction covering the whole tropical cyclone year from July to June. This year the BoM forecast that the cyclone season could start up to two weeks earlier than usual.
This year, the NCC forecast that the basin could turn into the most active season since 1983–84, with 20–22 tropical cyclones developing in or moving into the region, compared with an average of twelve tropical cyclones. For the western region, the NCC forecast that 11–12 tropical cyclones would develop in or pass through the region, compared to an average of seven. The NCC also predicted that 7–8 tropical cyclones would form or pass through the north-west region, compared to an average of six, while also predicting that five tropical cyclones would develop within the northern region. However, for both of these regions, the NCC noted that the model used for predicting cyclones in this area had a "low skill". For the eastern part of the basin the NCC reported that 6–7 tropical cyclones would develop and/or move through the region compared to an average of four.
City University of Hong Kong
Since the 2009-10 season, the Guy Carpenter Asia-Pacific Climate Impact Centre (GCACIC) at the City University of Hong Kong have issued a forecast that predicts the annual number of tropical cyclones that will affect the Australian region, and its 2 subregions Eastern and Western Australia. This season the GCACIC predicted that 19 tropical cyclones would either develop within or move into the basin compared to an average amount of 12 - 15. For the Western Australia subregion between 90°E and 135°E, the GCACIC predicted that 14 tropical cyclones would either develop or move into the region, compared to an average of 9 - 10 tropical cyclones. For the Eastern Australia subregion between 135°E and 160°E, the GCACIC predicted that 7 tropical cyclones would develop or move into the region, compared to an average of 5-6 tropical cyclones.
On 28 October, TCWC Perth and TCWC Jakarta started to monitor a tropical low that had developed to the southwest of Sumatra in Indonesia. Over the next few days as the low drifted towards the west, the systems low level circulation centre gradually developed further while drifting towards the west, before late on 30 October, the JTWC started warning on the low as Tropical Cyclone 02S. During the next day TCWC Perth and TCWC Jakarta both reported that the low had developed into a category 1 tropical cyclone on the Australian scale, with the latter naming it Anggrek. Later that day, as Anggrek moved into TCWC Perths area of responsibility it was reported that Anggrek had further intensified into a Category 2 Tropical Cyclone. Anggrek then passed to the east of the Cocos (Keeling) Islands early on 2 November. Later that day, after passing to the east of the Cocos (Keeling) Islands, TCWC Perth reported that Tropical Cyclone Anggrek had weakened into a Category 1 Cyclone. Anggrek continued to weaken, and on 4 November, the TCWC Perth reported Anggrek had become a Tropical Low, and issued their final advisory on the system.
Throughout the Cocos (Keeling) Islands, heavy rain and gusty winds were experienced as Cyclone Anggrek passed. Only minor damage was reported, with several trees and power lines brought down. No deaths have been reported across the islands. In post storm analysis, TCWC Perth declassified Anggrek as a tropical cyclone because gale force winds never extended more than halfway around the system center.
On 29 November, TCWC Perth reported that Tropical Low 02U had formed within the South-West Indian Ocean. Later that day, both the RSMC La Reunion and the JTWC started to monitor the low, designating it as Tropical Disturbance 02 and Tropical Cyclone 03S respectively. On 2 December, RSMC La Reunion reported that it had intensified into a moderate tropical storm and named it "Abele". On 3 December, Abele moved southeast and crossed 90°E as a Category 2 tropical cyclone when RSMC La reunion released their final advisory. Later that day, BoM took the full responsibility of monitoring the system and initiated warnings on Abele as a Category 1 tropical cyclone. On 4 December, Abele turned south-southeast while continuing to weaken further. The BoM then downgraded Abele into a tropical low and issued their final advisory. The remnants of Abele continued to weaken as they slowly moved southeast, before dissipating completely on 6 December.
On 15 December a monsoonal low developed about 500 km north-west of Exmouth, Western Australia. The system drifted slowly to the south-east. Gales and heavy rain reached areas far from the centre of the system which crossed the coast near Coral Bay on 18 December. However, shortly after landfall the system turned sharply to the south-west and reached the Indian Ocean west of Carnarvon on 19 December. It moved away from the coast and dissipated late on 20 December some 500 km west of Geraldton.
In the catchment basin of the Gascoyne River heavy precipitation fell from 16 to 19 December and triggered one of the worst floods along the Gascoyne River in history. The rain also affected other river basins in the area, such as Wooramel, Murchison, Lyndon-Minilya, and Ashburton rivers. For the period from 16 to 20 December some stations reported up to 300 mm cumulated precipitation which is equivalent to the normal annual rainfall amount. The highest 24 hours rainfall was reported at Carnarvon Airport on 17 December. During that day 207.8 mm fell which set an all time record since recording began in 1883 with the previous record 119.4 mm set on 24 March 1923.
Preliminary estimates placed damage at A$100 million (US$100.4 million) with at least 2000 head of cattle lost in the flood.
In late December, a low pressure area was tracked for several days moving westwards towards Queensland. Early on Christmas Day (local time) it strengthened rapidly and was designated Tropical Cyclone Tasha when it was 95 km (59 mi) east northeast of Cairns. The cyclone crossed the coast between Cairns and Innisfail at about 5:30 am, with wind gusts of up to 105 km/h (65 mph) recorded off the coast. Rainfall of about 100 mm was recorded in the space of an hour. Damage from associated flooding was estimated at A$1 billion.
At the end of December, a Tropical Low developed inland over the Top End of Western Australia. On 30 December, the TCWC Perth initiated cyclone advisories, as the system was initially forecasted to move off the coast of Western Australia, and strengthen into a Tropical Cyclone. Later on the same day, Tropical Low 06U moved off the coast of Western Australia, as expected, and slowly began to strengthen. After that, the low continued to strengthen, as it moved farther out west in the Indian Ocean. But before it could reach Tropical Cyclone intensity, Tropical Low 06U dissipated completely on 4 January, and the BoM issued its final advisory on the system.
At midnight, 10 January, The Bureau of Meteorology (BoM) reported that a Tropical Low developed off the coast of Western Australia. The system gradually intensified and became a Category 1 tropical cyclone on 12 January, receiving the name "Vince". The cyclone was initially expected to reach Category 2 status, but it became less well organised and lost cyclone intensity on 14 January.
A tropical depression formed in the Coral Sea east of Cairns on 13 January. The depression intensified into a Tropical Cyclone on 14 January, and given the name "Zelia". It strengthened rapidly and became the first severe tropical cyclone of the season on 15 January. Moving quickly to the south-east it crossed the 160°E meridian into the Pacific Basin on 16 January, after impacting New Zealand as an extratropical system.
On 22 January Tropical Cyclone Warning Centre in Brisbane (TCWC Brisbane) upgraded an area of low pressure to the North East of Cairns into a tropical low and designated it with '11U'. At midnight that day, TCWC Brisbane further upgraded the system into a Category 1 Tropical Cyclone and named it 'Anthony'. Soon Afterwards, the Joint Typhoon Warning Center (JTWC) began monitoring the system as 'Tropical Cyclone 09P'. On the next day, the system moved into the South Pacific Ocean and weakened into a Tropical Low. On 25 January, the low moved back into the Australian region and started intensifying with that the JTWC issued a Tropical Cyclone Formation Alert stating that the system could redevelop into a Tropical Cyclone. On 28 January, TCWC Brisbane reported that the system regenerated into a Tropical Cyclone. Tropical Cyclone Anthony made landfall near Bowen, at Category 2 strength, late on 30 January.
Early on 21 January the Tropical Cyclone Warning Centre (TCWC) in Darwin reported that a tropical low formed in the Gulf of Carpentaria and gave it the identifier '12U'. Gradual strengthening took place and on 25 January, the Joint Typhoon Warning Center (JTWC) began monitoring the system as Tropical Cyclone 10P. A few hours later, TCWC Perth upgraded the low into a Category 1 Tropical Cyclone, naming it Bianca. Early on the next day, TCWC Perth further upgraded Bianca to a Category 2 Tropical Cyclone. Intensification continued and late on the same day, TCWC Perth upgraded Bianca into a Category 3 Severe Tropical Cyclone. The system continued to intensify and became a Category 4 severe tropical cyclone on 28 January. On the same day, the system started weakening rapidly and TCWC Perth downgraded Bianca into a Category 3 Severe Tropical Cyclone.
Rain and strong winds were experienced along the Kimberley coast on 25 January. On 26 January, Bianca moved away from Kimberley and weather conditions started to improve. Bianca disrupted operations in Australia's major iron ore port and several oil facilities. In Western Australia, preparations were underway as the system was soon expected to approach land. As soon as Bianca became a category 3 Severe tropical cyclone, strong winds lashed through Pilbara suspending Oil and gas production and port facilities. Though Bianca was moving away and the level of risk was going down, coastal communities between Onslow and Exmouth remained on a red alert as the system intensified. On 28 January, according to the media, there was a chance for Bianca to start weakening, as it was moving further south into a colder, high pressure zone.
Severe Tropical Cyclone Bianca was expected to make landfall around Mandurah as a weak Category 1 or strong Tropical Low late on 30 January. A Cyclone Warning was activated for the area between just north of Jurien Bay and Albany, including Perth. The warnings were cancelled on 30 January, however, as Bianca dissipated south of Western Australia on the afternoon of 30 January. The airmass around Bianca was responsible for giving Perth and the Southwest of WA a taste of the tropics with severe thunderstorms, unrelated to Bianca, springing up on Saturday 29th causing damage in the Geraldton region. Two deaths were attributed to damaging severe thunderstorms that formed along the storm's outer bands.
Yasi entered the Australian region from the South Pacific basin on 31 January. By the time Yasi crossed into the basin, preparations for the storm were under way. Media outlets referred to the storm as "what could be the state's worst cyclone in history." Many feared that the tropical cyclone could cause damage more severe than Cyclone Larry in 2006 and Cyclone Tracy, which nearly destroyed Darwin, in 1974. Thousands of residents in the path of the storm were urged to evacuate by Premier Anna Bligh.
Yasi crossed the Queensland coast near Mission Beach shortly after midnight (local time) on 3 February. At that time, the large destructive core around the eye extended between Innisfail and Cardwell, Queensland. Yasi was the second costliest tropical cyclone in Australia's history after Cyclone Tracy, as well as the costliest without inflation. Yasi caused at least 3.6 billion (2011 USD) in damage. One death occurred due to asphyxiation in Ingham.
A low formed off the Western Australian coast on 8 February and drifted steadily west south west for the next few days. On 11 February, the Bureau of Meteorology identified the system as Tropical Low 15U and began monitoring the system for further development. Later that day, the JTWC began issuing advisories on the system under the name 14S. The storm was expected to reach minimal category 1 cyclone intensity (Australian scale) on 12 February but high shear, cool sea temperatures and poor organisation saw the system stay as a low.
A low developed off the Western Australian coast on 11 February and strengthened on 15 February.
The Bureau of Meteorology issued a Cyclone watch later in the day reported that a tropical low formed 350 km (220 mi) NNW of Exmouth. A Cyclone watch had been issue for the coastal communities between Onslow to Coral Bay. Late on 16 February, the low formed into Tropical Cyclone Dianne whilst 445 km NW of Exmouth. Dianne, as expected, intensified, and was upgraded to a Category 2 cyclone on 18 February whilst slowly moving towards the SSW. On 19 February the system intensified into a Category 3 severe tropical cyclone.
By late 21 February the system lost its strength as it moved into colder waters and was downgraded to a Category 1 Tropical Cyclone, and by 22 February it was classified as an ex-Tropical low.
On 14 February the Tropical Cyclone Warning Centre (TCWC) in Darwin reported that a tropical low formed near latitude 13.2S, longitude 130.7E, about 40 km (25 mi) west southwest of Batchelor. A severe weather warning was issued for northwest Darwin-Daly District and the Tiwi Islands. Heavy rain pounded the area on 15 February with reports of Marrara recording 179.4 mm (7.06 in) and Darwin International Airport 131.0 mm (5.16 in) of rain. This was later followed by 339.6 mm (13.37 in) of rain in just 24 hours, which is the highest 24-hour rainfall for the city on record.
On 16 February the slow moving system strengthened into Tropical Cyclone Carlos causing localised flooding and damage to homes, with fallen trees. Schools in Darwin, Darwin International Airport and East Arm Wharf were closed. After looping around the Darwin area overnight and back over land the system weakened on 17 February and BOM downgraded it to a Tropical low. A record three day total of 684.8 mm (26.96 in) rain was recorded at Darwin International Airport due to the lingering of the system.
The system moved slowly southwest on 18 February moving towards the Northern Territory/Western Australian border with a possibility of restrengthening. The community of Daly River received 442 mm (17.4 in) of rainfall. On 19 February the system passed into the Northern Kimberley region. Rainfall totals were not as large as in previous days. Wyndham recorded 90 mm (3.5 in) while Kalumburu recorded 80 mm (3.1 in) of rainfall.
In the early hours of 21 February the system returned to the open waters of the Indian Ocean, causing it to redevelop back into a cyclone. The system was located 75 km (47 mi) northwest of Broome. The cyclone continued to track southwest at a relatively fast pace and produced a squall line that generated four tornadoes in the mining town of Karratha which damaged 38 homes as well as numerous cars, buildings and a school. It also strengthened steadily to become a category 2 cyclone.
On 22 February the system moved parallel to the Pilbara coast. Varanus Island recorded 59 mm (2.3 in) of rainfall and the highest wind gusts in the area was 120 km/h (75 mph) at Bedout Island. The system became more organised and on 23 February the record rainfall amount of 283 mm (11.1 in) was recorded at Barrow Island. The strongest gusts of 139 km/h (86 mph) recorded at Varanus Island. The cyclone crossed the North West Cape and lashed Onslow and Exmouth with high winds up to 155 km/h (96 mph) and rain.
As Carlos moved away from the western coast of Australia on 24 February it strengthened into a Severe Tropical Cyclone.
On 25 February, the Tropical Cyclone Warning Centre (TCWC) in Perth
reported that a tropical low formed estimated to be 75 km (47 mi) west northwest of Kalumburu and 445 km (277 mi) northeast of Derby and moving slowly southwest parallel to the north Kimberly coast. In the early hours of 28 February the tropical low moved inland from King Sound. Heavy rainfall was reported on the Dampier Peninsula east and southeast of Port Hedland, including Telfer and parts of the De Grey catchment. Derby recorded 83 mm (3.3 in) of rain while Camballin received 142 mm (5.6 in) and the aboriginal community of Looma had 105 mm (4.1 in). The tropical low continued moving overland and the BOM issued their final advice on 28 February.
On 10 March TCWC Perth reported that Tropical Low 23U, had developed within TCWC Jakarta's area of responsibility about 1,640 km (1,020 mi) to the east of Jakarta, Indonesia. Over the next couple of days the low remained slow moving. On 13 March, the low briefly moved into TCWC Perth's area of responsibility, before crossing 90°E and moving out of the Australian region and into the South-West Indian Ocean. It later developed into Tropical Storm Cherono.
On 26 March, Tropical Low 25U formed off the northern coast of Australia. By 31 March, the tropical low was reported to be north-west of Darwin and slowly moving towards the Kimberley region, which is already struggling to cope with severe flooding from previous storms. On 6 April, the tropical low dissipated completely.
to the northwest of the Cocos islands. Over the next couple of days the low moved towards the west and briefly moved into the South West Indian Ocean. However, on 2 April, Tropical Low 27U dissipated completely over open waters.
A Tropical Low formed north of the Tiwi Islands on 10 April and developed slowly as it moved westwards. It was upgraded on the 15th of April and was named 'Errol'. Errol moved southward slowly, over the next couple of days. On 20 April, Errol dissipated.
↑Australian tropical cyclone warning centers (29 August 2012). The Australian tropical cyclone track database (.CSV). Australian Bureau of Meteorology. “This system was downgraded to a low by post analysis as gales never extended more than halfway around the system centre.”