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Cyclone Waka

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Severe Tropical Cyclone Waka
Category 4 severe tropical cyclone (Aus scale)
Category 3 tropical cyclone (SSHWS)
Cyclone Waka near peak intensity shortly after moving through Tonga
FormedDecember 19, 2001
DissipatedJanuary 2, 2002
Highest winds10-minute sustained: 185 km/h (115 mph)
1-minute sustained: 185 km/h (115 mph)
Gusts: 250 km/h (155 mph)
Lowest pressure930 hPa (mbar); 27.46 inHg
Fatalities1 indirect
Damage$51.3 million (2002 USD)
Areas affectedWallis and Futuna, Niue, Tonga; especially Vava'u, and New Zealand
Part of the 2001–02 South Pacific cyclone season

Severe Tropical Cyclone Waka (Fiji Meteorological Service designation: 03F, Joint Typhoon Warning Center designation: 07P) was one of the most destructive tropical cyclones to ever impact the South Pacific kingdom of Tonga. The precursor to Waka formed out of a near-equatorial trough in mid-December 2001. Remaining relatively weak, this system struggled to gain strength for more than a week. The storm gradually organized and attained tropical cyclone status on December 29. Rapid intensification took place shortly thereafter as Waka moved through several countries. The storm attained its peak intensity as a Category 4 severe tropical cyclone on December 31 with winds of 185 km/h (115 mph). Shortly thereafter, it passed directly over Vava'u, resulting in widespread damage. By January 1, 2002, the cyclone began to weaken as it underwent an extratropical transition which it completed the following day. The remnants of Waka persisted for several more days and were last noted near the Southern Ocean on January 6.

Throughout Waka's path, several countries were impacted by the storm; however, the most significant losses took place in Tonga. There, one person was killed and 104.2 million paʻanga ($51.3 million USD) was wrought in damage. Hundreds of structures and much of the nation's agriculture were destroyed. Winds in excess of 185 km/h (115 mph) battered Vava'u, destroying 200 homes in the island's largest city. In addition to infrastructural and public losses, the environment was also severely affected; a native species of bats lost roughly 80% of its population due to the lack of fruit. Following the storm, Tonga requested international aid to cope with the scale of damage. Due to the severity of damage, the name Waka was later retired and replaced with Wiki. According to a study by Janet Franklin (et al.), storms similar in intensity to Waka, on average, strike Tonga once every 33 years.[1]

Meteorological history

Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
Map key
Saffir–Simpson scale
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
triangle Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression

In mid-December 2001, at the end of a Madden–Julian oscillation phase, twin equatorial monsoonal troughs developed in the Northern and Southern Hemispheres. Although warm sea surface temperature in the region favored development, the southern trough developed substantially slower than the northern one.[2] On December 19, the southern component was classified as Tropical Depression 03F by the Regional Specialized Meteorological Centre in Nadi, Fiji (Fiji Meteorological Service); at this time the depression was situated just east of the Solomon Islands.[3] The northern component eventually developed into Typhoon Faxai, an extremely powerful Category 5 equivalent cyclone.[4] Unlike Faxai, the precursor to Cyclone Waka developed slowly, mainly due to moderate wind shear in the region. Moving southeastward, the system gradually became more organized.[2] On two occasions, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert; however, later cancelled them both times.[5] By December 27,[2] the system entered a region that favored significant development, featuring sea surface temperatures of 30 °C (86 °F) and low shear.[3] The following day, the JTWC classified the system as Tropical Depression 07P.[6]

Tracking towards the southwest in response to a mid-level ridge to the southeast, the depression quickly intensified, attaining gale-force winds on December 29. Upon doing so, it was upgraded to a tropical cyclone and given the name Waka. Shortly thereafter, the storm underwent rapid intensification;[2] roughly 24 hours after being named, Waka was upgraded to a severe tropical cyclone, attaining sustained winds of 120 km/h (75 mph).[7] During December 30, the centre of the storm brushed Wallis Island before turning towards the southeast and accelerating. Continuing to intensify, Waka passed directly over Niuafo'ou on December 31 with winds of 150 km/h (90 mph).[2] Later that day, the cyclone attained its peak intensity as a Category 4 severe tropical cyclone with ten-minute sustained winds of 185 km/h (115 km/h) and a barometric pressure of 930 mbar (hPa; 27.46 inHg).[2] The JTWC assessed the storm to have attained similar one-minute sustained winds upon peaking.[6] At this time, Waka displayed a well-defined, circular eye roughly 60 km (37 mi) in diameter. Shortly after attaining its peak intensity, the centre of Waka passed over Vava'u.[2]

Continuing into the new year, Waka gradually weakened on January 1, 2002 as it entered a less favorable region. As a result, convection was sheared away from the centre and its eyewall broke apart. Moving over decreasing sea surface temperatures, Waka began to undergo an extratropical transition, which it completed on January 2.[2] Tracking southeastward, the remnant cyclone briefly slowed over open waters before again accelerating to the southeast. Over the following few days, the system gradually weakened. By January 5, the cyclone's winds decreased below gale-force. The storm was last noted on January 6 near the Southern Ocean, at which time it had a pressure of 972 mbar (hPa; 28.7 inHg).[7]

Preparations and impact

Tonga

On December 30, just a day before Waka passed through Tonga, warnings were issued for numerous islands, including parts of Fiji and Samoa. Forecasts showed the storm passing directly over the low-lying Tongan capital of Nuku'alofa as a Category 3 cyclone.[8] Due to warnings from local media,[9] all New Year's Eve celebrations were canceled as residents and tourists boarded up their homes. All airports in the region were shut down and ferry service was suspended.[10] Many residents on the small island of Niuafo'ou, about 35 km2 (13.5 mi2) in size, evacuated to other islands prior to Waka's arrival.[11]

Infrared satellite image of Cyclone Waka passing directly over Vava'u on December 31

Moving through the islands of Tonga at peak strength, a few islands recorded hurricane-force winds; the city of Neiafu measured the strongest winds, peaking at 185 km/h (115 mph). In the southern islands, wind gusts up to 250 km/h (155 mph) were estimated to have impacted isolated communities. In the Haʻapai islands, sustained winds reached 100 km/h (65 mph) and gusted to 140 km/h (85 mph).[12] Heavy rains also fell during Waka's passage, amounting to over 200 mm (7.9 in) in Haʻapai.[13]

Initial reports from Nuku'alofa on December 31 indicated severe agricultural damage but little infrastructural losses.[14] Following the passage of Waka, communication with Niuas and Vava'u were lost.[15] According to local reports, nearly every tree in Neiafu had been downed by high winds and much of the island was sandblasted. Numerous homes were destroyed and those that were left standing lost their roofs.[16] According to the Red Cross, about 200 homes in the city were severely damaged or desroyed.[17] Throughout Vava'u, roughly 90% of the island's crops were destroyed, including essential food crops such as taro, yams and bananas. In Ha'apai, one person died from cardiac arrest as brought on by the storm. Numerous roads were blocked by fallen trees, power and water supplies were also interrupted to most residents. Severe damage also took place on Niuatoputapu where coastal homes were impacted by Waka's storm surge and several structures lost their roofs.[13] In one instance, a yacht was brought onshore by the surge and crashed into a restaurant, destroying both.[18]

According to damage surveys, 13 of the country's islands sustained damage;[19] 470 homes and six schools were destroyed and hundreds more were damaged.[20][21] In terms of monetary losses, damage from Cyclone Waka amounted to 104.2 million paʻanga ($51.3 million USD)[22][23] In addition to infrastructural and public damage, the environment sustained catastrophic losses. Throughout Tonga, a native species of flying foxes (bats; Pteropus tonganus) was vastly impacted by Waka. Compared to pre-cyclone population levels, 79.8% (±9.9%) of the species was killed across six islands. This was due to widespread destruction of their natural food source, which decreased by 85% (±11.8%) following Waka. Trees across Vava'u were completely defoliated,[19] although only 6.6% were killed,[1] leaving no food for the bats. The greatest decline in bats was on Utula'aina Island at 95.7%; A'a Island sustained the highest decrease in plants bearing food at 100%. Six months after the storm, the bat population in Vava'u was still only 20% of the pre-storm level.[19]

Elsewhere

Prior to impacting Tonga, Cyclone Waka caused significant damage in Wallis and Futuna and Niue. On Wallis Island, one home was destroyed and 50% of the banana crop was lost. A wind gust of 126 km/h (78 mph) and swells up to 7 m (23 ft) were recorded in Wallis. Niue received more significant damage, experiencing a storm surge of 8 m (26 ft) and sea spray up to 100 m (330 ft) inland. Numerous fallen trees and power lines blocked roads and left southern areas of the island without power for roughly six hours.[3]

After moving through the Tongan islands, the remnants of Waka brought large swells, estimated up to 2.5 m (8.2 ft), to the North Island of New Zealand. Thousands of residents and tourists were in the region following the New Year's holiday. Meteorologists warned that the oceans would be increasingly dangerous and advised people not to venture into the water. Every lifeguard in Whangamata was called in to assist in keeping and estimated 8,000 people out of the water. Former lifeguards were also called in to aid in this.[24] Although most people stayed within a designated swimming area, several rescues had to be made.[25] Rip currents also pulled 38 people out to sea in Mount Maunganui Main Beach; all were quickly rescued by lifeguards.[26]

Aftermath

Zoomed in track of Cyclone Waka between December 29 and January 1

Within a day of Cyclone Waka's passage in Tonga, the Government of New Zealand deployed an aircraft to survey the scale of damage and reestablish contact with the Tongan Islands.[16] On January 2, the head of Tonga's Disaster Office announced that they would likely need international assistance to recover from the storm.[27] Due to the substantial damage to agriculture, food shortages were expected to impact the region in the near future.[13] By January 7, the Red Cross began sending supplies to Tonga. Hundreds of tents and tarpaulins were brought in by an Australian AC-130 to help with the recovery process.[28] On January 12, a New Zealand aircraft carrying US$700,000 worth of supplies flew to the area to deliver aid.[29] An additional US$700,000 was given in relief funds to repair damage wrought by the storm. Of this, US$500,000 would be used to repair schools that were damaged or destroyed and the remaining US$200,000 would be used for emergency lighting, cooking and food supply recovery.[20][30]

Further funds came from the United States, which offered US$25,000 by mid-January.[31] The French Polynesian assembly in Tahiti also provided US$770,000 worth of relief supplies and aid.[32] The main industry of Tonga, tourism, was devastated by the storm as no tourists were allowed to travel to the region for at least two weeks after Waka's passage.[33] The Government of Tonga requested a total of US$39.2 million in international aid, most of which was dedicated to rehabilitation. Medical supplies and personnel were later deployed by the World Health Organization.[34] About 180 people were given assistance in rebuilding their homes by the Church World Service in mid-March.[35] Owing to the severity of damage wrought by the cyclone, the World Meteorological Organization retired the name Waka following its using and replaced it with Wiki.[36]

See also

References

  1. ^ a b Janet Franklin, Donald R. Drake, Kim R. McConkey, Filipe Tonga and Leslie B. Smith (2004). "The Effects of Cyclone Waka on the Structure of Lowland Tropical Rain Forest in Vava'u, Tonga". Journal of Tropical Ecology. 20 (4). Cambridge University Press: 409–420. doi:10.1017/S0266467404001543. Retrieved December 4, 2010.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ^ a b c d e f g h Jonty D. Hall (2004). "The South Pacific and southeast Indian Ocean tropical cyclone season 2001-02" (PDF). Australian Meteorology Magazine. 53 (4). Queensland Regional Office, Bureau of Meteorology, Australia: 285–304. Retrieved December 5, 2010.
  3. ^ a b c Gary Padgett (May 24, 2002). "Monthly Tropical Weather Summary for December 2001" (TXT). Typhoon 2000. Retrieved December 4, 2010.
  4. ^ Joint Typhoon Warning Center (2002). "2001 Annual Tropical Cyclone Report" (PDF). United States Navy. Retrieved December 5, 2010.
  5. ^ Gary Padgett (January 21, 2002). "Monthly Tropical Cyclone Tracks for December 2001" (TXT). Typhoon 2000. Retrieved December 5, 2010.
  6. ^ a b Joint Typhoon Warning Center (2003). "Tropical Cyclone 07P (Waka) Best Track" (TXT). United States Navy. Retrieved December 5, 2010.
  7. ^ a b "Best Track Data for 1967-2006" (XLS). Tropical Cyclone Warning Centre in Wellington, New Zealand. 2007. Retrieved December 5, 2010.
  8. ^ Agence France-Presse (December 30, 2001). "Severe cyclone bearing down on South Pacific islands". ReliefWeb. Retrieved December 2, 2010.
  9. ^ Agence France-Presse (December 31, 2001). "South Pacific cyclone intensifies - Tonga at risk". ReliefWeb. Retrieved December 2, 2010.
  10. ^ Paul Yandell (January 1, 2002). "Tonga battens down as Cyclone Waka roars in". The New Zealand Herald. {{cite news}}: |access-date= requires |url= (help)
  11. ^ "Cyclone Waka heads out into Pacific after lashing Tonga". The Dominion. January 2, 2002. {{cite news}}: |access-date= requires |url= (help)
  12. ^ "Cyclone Waka Batters Tonga". The Press. January 2, 2002. {{cite news}}: |access-date= requires |url= (help)
  13. ^ a b c East-West Center (January 3, 2002). "Damage from Cyclone Waka to Vava'u runs in millions of Pa'anga". ReliefWeb. Retrieved December 2, 2010.
  14. ^ United Nations Office for the Coordination of Humanitarian Affairs (December 31, 2010). "Tonga - Tropical Cyclone Waka OCHA Situation Report No. 1". ReliefWeb. Retrieved December 2, 2010.
  15. ^ Agence France-Presse (January 1, 2002). "Tongas northern group hit by cyclone - heavy damage feared". ReliefWeb. Retrieved December 2, 2010.
  16. ^ a b Deutsche Presse Agentur (January 1, 2002). "New Zealand Air Force sending plane to check Tonga cyclone damage". ReliefWeb. Retrieved December 2, 2010.
  17. ^ Reuters (January 3, 2002). "Red Cross seeks food aid after Tonga cyclone". ReliefWeb. Retrieved December 2, 2010. {{cite web}}: |author= has generic name (help)
  18. ^ Paul Yandall (January 2, 2002). "Battered Tonga struggles to mop up". The New Zealand Herald. {{cite news}}: |access-date= requires |url= (help)
  19. ^ a b c Kim R. McConkey, Donald R. Drake, Janet Franklin and Filipe Tonga (2004). "Effects of Cyclone Waka on flying foxes (Pteropus tonganus) in the Vava'u Islands of Tonga". Journal of Tropical Ecology. 20 (5). Cambridge University Press: 555–561. doi:10.1017/S0266467404001804. Retrieved December 4, 2010.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  20. ^ a b "New Zealand to give Tonga 700,000 dollars for cyclone relief". Radio New Zealand International. January 8, 2002. {{cite news}}: |access-date= requires |url= (help)
  21. ^ Emily McKenzie, Biman Prasad and Atu Kaloumaira (May 2005). "Economic Impact of Natural Disaster on Development in the Pacific". Australian Agency for International Development. Retrieved December 3, 2010.
  22. ^ Centre for Research on the Epidemiology of Disasters (2010). "International Disaster Database: Disaster List". Retrieved December 3, 2010.
  23. ^ United Nations Office for the Coordination of Humanitarian Affairs (January 23, 2002). "OCHA Situation Report No. 2". Center for International Disaster Information. Retrieved December 5, 2010.
  24. ^ "Cyclone whips up surf scare on beaches". The New Zealand Herald. January 4, 2002. {{cite news}}: |access-date= requires |url= (help)
  25. ^ Josie Clark (January 5, 2002). "Big waves create busy day for lifeguards". The New Zealand Herald. {{cite news}}: |access-date= requires |url= (help)
  26. ^ "38 swimmers rescued off Mt. Maunganui Beach". The New Zealand Herald. January 5, 2002. {{cite news}}: |access-date= requires |url= (help)
  27. ^ Australian Broadcasting Corporation (January 2, 2002). "Tongan authorities assess damage from cyclone Waka". ReliefWeb. Retrieved December 2, 2010.
  28. ^ Francesca Mold (January 7, 2002). "Tonga picks up the pieces left by Cyclone Waka". The New Zealand Herald. {{cite news}}: |access-date= requires |url= (help)
  29. ^ "New Zealand air force drops off relief supplies to cyclone-hit Tonga". BBC. January 12, 2002. {{cite news}}: |access-date= requires |url= (help)
  30. ^ "NZ offers $ 700,000 to Tonga". The Press. January 9, 2002. {{cite news}}: |access-date= requires |url= (help)
  31. ^ Pacific Islands Broadcasting Association (January 17, 2002). "Tonga: US donates $25k for cyclone relief". ReliefWeb. Retrieved December 3, 2002.
  32. ^ Pacific Islands Broadcasting Association (January 21, 2002). "Tahiti approves US$770,000 Tonga aid package". ReliefWeb. Retrieved December 3, 2010.
  33. ^ Paul Yandall (January 3, 2002). "NZ ready with food for Tonga". The New Zealand Herald. {{cite news}}: |access-date= requires |url= (help)
  34. ^ United Nations Office for the Coordination of Humanitarian Affairs (February 6, 2002). "Tropical Cyclone Waka OCHA Situation Report No. 3". ReliefWeb. Retrieved December 3, 2010.
  35. ^ Church World Service (March 18, 2002). "CWS helps vulnerable families rebuild cyclone-destroyed houses in Tonga". ReliefWeb. Retrieved December 3, 2010.
  36. ^ "Tropical Cyclone Operation Plan for the South Pacific and South-East Indian Ocean" (PDF). World Meteorological Organization. 2008. Retrieved December 5, 2010.
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