Cyclone Nancy
Cyclone Nancy was the second in a series of four severe tropical cyclones in February 2005 in the Cook Islands. Nancy developed on February 10 from a low pressure area and organized rapidly to a small, but intense tropical cyclone. After an explosive intensification of the cyclone reached Category 4 according to the Australian scale, with ongoing, ten-minute wind speeds [Note 1] of 175 km / h and a minimum air pressure of 935 hPa in the course of the following day the storm wind shear weakened emerging rapidly. He transistierte on February 17 in an extratropical cyclone, which was absorbed shortly thereafter by Cyclone Olaf.
In the Cook Islands, which have already been hit by Cyclone Meena early February cyclone Nancy taught at major damage. Several homes were damaged on the islands and destroyed, torn down power lines and fallen trees broke the power and blocked roads. From the coastal areas of flooding were reported. As a result of the impact of the storm, the World Meteorological Organization has the name Nancy removed from the list of names of tropical cyclones and replaced by Nat.
Storm History
Cyclone Nancy was born on February 10 from a vast area of low pressure within the monsoon trough northeast of Samoa. First, the system remained nearly stationary in an area with weak currents control, low level wind shear and high water temperatures above 30 ° C. On February 11, amplified a trough for a short time the wind shear in the area of the system and its twin, which nearby precursor system to cyclone Olaf. On February 12, at 6:00 UTC clock, the outflow of the system had improved and a small area of deep atmospheric convection developed over the center of circulation. During the day, the Regional Specialized Meteorological Centre ( RSMC ) in Nadi, Fiji, the system to a Category 1 cyclone on the Australian scale classified high and gave him the name Nancy, as it is around 485 km eastern north-east of Pago Pago in American Samoa was. At that time, the Joint Typhoon Warning Center ( JTWC ) also had begun with the issue of storm warnings and led the system, called 18P.
The storm was hiking in the early morning of February 13 first slowly to the northeast, before he turned off ¨ because of a subtropical ridge northeast of the system to the southeast. Rain bands developed near the circulation center, as the storm of explosive intensification underwent. Around 12:00 UTC clock the storm reached the status of a severe tropical cyclone, as the ongoing ten-minute wind speeds around 120 km / h and reached a small, irregularly shaped eye trained. The JTWC assessed the intensity of the cyclone, however, to clock at 0:00 UTC on 14 February is much weaker. At this time, reported Pearl Harbor one-minute sustained winds of 95 km / h, which corresponds to a weak hurricane of Category 3 of Saffir -Simpson Hurricane Scale.
On February 14, at 12:00 UTC Clock Nancy reached its maximum intensity with ten-minute wind speeds of 175 km / h and a central pressure of 935 hPa. ( The JTWC took the peak intensity with continuous one-minute wind speeds of 230 km / h. ) Increased forward speed to the southeast and wind shear to what Nancy weakened. Early in the morning of the 15th February, the cyclone moved directly across Manuae. The slowdown continued further, when a trough approached from the southwest. On 16 February, the winds reached gale force only. Nancy turned as a result of Fujiwhara effect in interaction with the more northerly cyclone Olaf to the southwest.
Strong wind shear, which was in connection with the discharge of Cyclone Olaf, led to the complete associated with Nancy convection was shifted to the southwest on February 16. In the early 17th February Nancy transistierte in an extratropical cyclone. At this time, the system came under the responsibility of the Tropical Cyclone Warning Centre ( TCWC ) in Wellington. Shortly thereafter, Nancy was absorbed by the greater circulation of cyclone Olaf. However, the TCWC in Wellington watched Nancy yet to 12:00 clock UTC on February 18, even as a standalone system.
Differences between the warning centers s
The RSMC Nadi used ten-minute sustained wind speeds, while the Joint Typhoon Warning Center for its primarily directing the organizations of the United States used the warnings based on one-minute wind speed criteria of the National Hurricane Center. The conversion factor between the two methods was set at 1.14. The greatest intensity was determined by RSMC Nadi for cyclone Nancy 175 km / h with ten-minute wind speeds, which corresponds to 205 km / h at one-minute wind speeds. The peak intensity determined the JTWC with 230 km / h, equivalent to 205 km / h at a ten minute observation.
Preparations
After assigning a name on February 13, a storm warning for American Samoa was triggered. During the day the storm warnings and strong wind warnings were extended to four states in the region, Samoa, Tuvalu, Tokelau and the Cook Islands. On 14 February, cyclone warnings for the southern Cook Islands and on February 14, a tropical cyclone alert which a declared for the southern Cook Islands. In addition, a strong wind warning was issued for Niue, during the day this has been extended to Wallis and Futuna. On February 15, hurricane warnings were declared for the southern Cook Islands, moved as a cyclone Nancy over the archipelago.
Already by the effects of the cyclone Meena previously startled just a week, the people of the Cook Islands followed the warnings and brought in emergency shelters. Coastal areas where the coast guard has been damaged or destroyed by Meena, particular attention was paid to the warning centers, which exhorted the people living in the nearby residents to seek shelter. Even tourists were brought from hotels in one of the six shelters on the islands. In broadcasting, the population was asked all day to get to safety and had shifted their staff in readiness the authorities. On Rarotonga eight emergency shelters were provided. For particularly low-lying areas the residents were evacuated because it was believed that the sea flooded these areas. The schools on the islands were closed before the arrival of the cyclone until the storm had passed. Many of the islands in the South Pacific were due to the rapid succession of four cyclones in a critical situation.
Impact and consequences
The cyclone Nancy caused significant damage in the Cook Islands. On Atiu, the communication links were completely interrupted because the power lines were torn down on the island. On the island peak gusts of 241 km / h were measured. Four houses were destroyed and at least 80 trees uprooted, so the roads were all impassable. At several houses, the roofs were covered and the roads were covered by rubble and torn down coconuts. On the islands, heavy rains came down. Numerous trees were uprooted by the storm on Manuae and Mauke. There are four houses were destroyed on Mitiaro held three houses the storm was not. Also on this island were all the roads blocked by fallen trees.
On Rarotonga damaged high waves due to the cyclone several bridges. Also, schools, churches and restaurants were pulled by wind gusts of up to 150 km / h in affected. Fifteen temporary shelters that were built after the passage of cyclone Meena, Nancy cyclone destroyed. The strongest winds were measured in the southern parts of the island chain, a gust of wind on Mangaia reached 259 km / h In some places, the seasonal crop was completely destroyed by the cyclone.
Due to the effects of four solid cyclones asked the Cook Islands for international help. A total of 7.87 million U.S. dollars ( 2005, adjusted for inflation 9,757,735 U.S. dollars) were placed on assistance available. The Red Cross emergency supplies such as blankets, tents and lanterns available, the Pacific Forum provided assistance in the form of food, fuel and logistical support to the value of $ 32,000, the Government of the People's Republic of China was 19,200 U.S. dollars and the United Nations Development programs $ 32,000. Through the Australian Agency for International Development and New Zealand Aid total of 862 570 U.S. dollars have been applied, including in the form of fuel, tents and financial resources. The Australian Government provided equipment worth 128,000 U.S. dollars available and the French government sent military personnel with supplies and tents. The European Union has provided € 200,000 available.
As Nancy caused significant damage in the Cook Islands, the name was removed from the name list A for the South Pacific and replaced by Nat. (Also Meena, Olaf and Percy. ) The other three cyclones impact in the region, were deleted and replaced by time, Olof and pita.