2010–11 South Pacific cyclone season
The 2010–11 South Pacific cyclone season was an average tropical cyclone season, with seven tropical cyclones and five severe tropical cyclones developing during the season. The season ran from November 1, 2010, until April 30, 2011, though if any tropical cyclones had developed between July 1, 2010, and June 30, 2011, the official tropical cyclone year, they would have been counted towards the season's total. Within the South Pacific basin tropical cyclones were officially monitored by the Fiji Meteorological Service's Regional Specialized Meteorological Center in Nadi, Fiji, north of 25°S, and to the south the Meteorological Service of New Zealand's Tropical Cyclone Warning Center in Wellington, New Zealand. Any disturbances forming in the region were designated with a sequential number suffixed by the letter F. In addition, the United States Military's Joint Typhoon Warning Center unofficially monitored parts of the basin during the season, where any systems judged to have achieved tropical storm strength or greater received a number suffixed with the letter P. RSMC Nadi and TCWC Wellington both use the Australian Tropical Cyclone Intensity Scale, and measure wind speeds over a period of ten minutes, while the JTWC measures sustained winds over a period of one minute which can be applied to the Saffir–Simpson hurricane scale. Seven named storms formed or moved into the South Pacific basin during the 2010–11 season, the strongest of which was Severe Tropical Cyclone Wilma in late January.
Seasonal outlooks
Ahead of the cyclone season, RSMC Nadi, TCWC Wellington, the Australian Bureau of Meteorology, the New Zealand National Institute of Water and Atmospheric Research and various other Pacific Meteorological services, all contributed towards the Island Climate Update tropical cyclone outlook that was released during October 2010. The outlook took into account the moderate-strong La Niña conditions that had been observed across the Pacific and analogue seasons that had La Niña conditions occurring during the season. The outlook called for a normal or above average number of tropical cyclone occurring during the season, with nine to twelve named tropical cyclones, to occur between 135°E and 120°W compared to an average of nine. At least three of the tropical cyclones were expected to become category 3 severe tropical cyclones, while one was expected to become a category 4 severe tropical cyclone. In addition to contributing towards the Island Climate Update outlook, RSMC Nadi and the BoM issued their own seasonal forecasts for the South Pacific region. The BoM issued 2 seasonal forecasts for the South Pacific region between 142.5°E – 165°E and one for the Eastern Southern Pacific region between 165°E – 120°W. They noted that the western region had a 79% chance of being above average activity with seven to eight tropical cyclones expected to form, compared to an average of five tropical cyclones. The eastern region had a 33% chance of being above average with five to six tropical cyclones predicted, compared to an average of seven tropical cyclones.Within their outlook RSMC Nadi predicted that between seven and nine tropical cyclones, would occur within the basin compared to an average of around 8.9 cyclones. They also reported that the tropical cyclone genesis trough was expected to be located within the Coral Sea area near to and to the west of the International Date Line. This was based on the expected and predicted ENSO conditions, and the existence of the Pacific warm pool of sub-surface temperature anomalies in this region. The Island Climate Update outlook assessed the risk of a tropical cyclone affecting a certain island or territory. As the tropical cyclone genesis trough was expected to be located within the Coral Sea area near to and to the west of the International Date Line, normal or slightly above normal activity was expected for island nations within the Coral Sea. It was also predicted that the risk of tropical cyclones affecting island nations located to the east of the International Date Line would be reduced during the season. It was predicted that Papua New Guinea, Vanuatu, New Caledonia, New Zealand and the Solomon Islands had an elevated chance of being affected by a single or multiple tropical cyclones. Fiji and Tonga were predicted to have a near normal chance, while other island nations had a low or reduced chance of being affected by a tropical cyclone.
Seasonal summary
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17 tropical disturbances developed during the 2010–11 South Pacific tropical cyclone year, with 14 developing into tropical depressions and 8 becoming tropical and severe tropical cyclones.
Systems
Tropical Depression 01F
The first tropical cyclone of the season, Tropical Depression 01F, was first identified on November 24 well to the west of Fiji. Little strengthening was anticipated to occur as the system slowly tracked towards the south-southeast. The following day, after an abrupt relocation to the southwest, the disturbance was assigned with the identifier 01F while situated near Vanuatu. Gradually strengthening, the disturbance was upgraded to a tropical depression on November 25 after a slight increase in convection. Situated along the eastern edge of an upper-level trough, the depression tracked towards the east-southeast and would keep this general motion for several days. Though situated over warm waters, estimated to be, persistent wind shear prevented the system from becoming organized.The system later relocated into a region less favorable for tropical cyclogenesis on November 27 but continued to strengthen and become better organized. Despite attaining gale-force winds, the depression was not classified as a tropical cyclone as these winds were located roughly 110 km from its center. During the afternoon of November 28, the depression attained a minimum barometric pressure of 999 hPa. Gradual weakening took place over the following few days as the system tracked southward. By November 30, the depression was declassified as a tropical cyclone and was last noted on December 1 near the International Date Line.
On November 26, a tropical cyclone alert was issued for Fiji as the depression was expected to bring heavy rains and strong winds to the region. Flooding was anticipated in low-lying areas and if further intensification took place, more significant damage would be expected. The alert was later raised to a cyclone warning as the system neared the country. All warnings associated with the depression were discontinued on November 29 as it moved away from Fiji. The system brought gusty winds and heavy rains to the islands of Vatulele and Kadavu, though no damage occurred.
Tropical Cyclone Vania
During January 5, RSMC Nadi reported that Tropical Disturbance 03F had developed, about to the northeast of Nadi, Fiji. Over the next few days the disturbance gradually developed further before RSMC Nadi classified it as a tropical depression early on January 9. On January 11, the Joint Typhoon Warning Center initiated warnings on the system and monitored it as Tropical Cyclone 05P. On the Next day, RSMC Nadi upgraded the depression into a Category 1 tropical cyclone and named it "Vania". Later that day, RSMC Nadi reported that Vania had intensified into a Category 2 tropical cyclone. Early the next day, RSMC Nadi upgraded Vania into a Category 3 severe tropical cyclone. Later that day, RSMC Nadi reported that Vania started weakening and downgraded it into a Category 2 tropical cyclone. Subsequently, it was downgraded to a category 1 tropical cyclone on January 14. On January 15, JTWC issued their final warning on the system. Soon, issuing their final advisory, RSMC Nadi downgraded Vania into a Tropical Depression.In Fiji, heavy rains associated with the initial disturbance brought significant flooding to many islands. Several roads were temporarily shut down due to rising waters, though no homes were affected. Although the center of Vania continued to move away from Fiji, the storm's outer bands brought continued rainfall to the country. As the storm passed through Vanuatu, winds of 140 km/h affected Tafea Province, and contact with this group of islands was lost. Many buildings were damaged and trees were felled. The National Disaster Management Office of Vanuatu enacted a 156.6 million vatu relief plan for Tafea Province, with the vast majority of funds going to food items. Within 24 hours of the storm's arrival in New Caledonia, a large magnitude 7.0 earthquake struck the Loyalty Islands within the archipelago. Media reported that extreme wind gusts up to were felt in the region. A boy died from heart attack after the dual strike of a tsunami warning from an earthquake and a red cyclone alert. Damage totaled to $11 million.