Severe Tropical Cyclone Ula
Ula at peak intensity southeast of Vanuatu on January 10
Meteorological history
FormedDecember 26, 2015
ExtratropicalJanuary 12, 2016
DissipatedJanuary 16, 2016
Category 4 severe tropical cyclone
10-minute sustained (FMS)
Highest winds185 km/h (115 mph)
Lowest pressure944 hPa (mbar); 27.88 inHg
Category 4-equivalent tropical cyclone
1-minute sustained (SSHWS/JTWC)
Highest winds220 km/h (140 mph)
Lowest pressure933 hPa (mbar); 27.55 inHg
Overall effects
Missing1 (presumed dead)
DamageMinimal
Areas affected
IBTrACS
Part of the 2015–16 South Pacific cyclone season

Severe Tropical Cyclone Ula was a powerful and long-lived tropical cyclone during late December 2015 and mid-January 2016. It originated from a tropical disturbance on December 26, 2015, east of the Solomon Islands. Moving generally east, development was initially slow and the system finally reached cyclone strength—having gale-force winds—on December 30. The newly christened Tropical Cyclone Ula turned sharply south and rapidly intensified, attaining hurricane strength the following day. A shift to the southwest brought the system close to the northern islands of Tonga on January 2, 2016. It subsequently brushed several islands in the Lau Group of Fiji before weakening. Nearly degrading to a tropical depression, Ula turned to the northwest and regained strength. After turning back to the southwest, it achieved its peak intensity as a Category 4 on the Australian scale with winds of 185 km/h (115 mph) on January 10. Thereafter, the storm bypassed Vanuatu to the southeast and New Caledonia to the east as it accelerated southward.

Throughout its existence, Ula affected several nations but its effects were largely limited, with only localized areas reporting damage. Dozens of structures were damaged or destroyed in Tuvalu while crops in Tonga, Fiji, and Vanuatu were impacted. No fatalities have been attributed to the storm, though one person was swept out to sea in American Samoa and was not found. Residents across the Lau Islands of Fiji required food security due to crop losses.

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 late December 2015, a long-lived and powerful westerly wind burst triggered the formation of a tropical disturbance in the south Pacific, along with its twin in the central North Pacific, which became Tropical Depression Nine-C.[1] On December 26, 2015, Fiji Meteorological Service (FMS) began monitoring the poorly-organized tropical disturbance, dubbed 05F, to the east of the Solomon Islands. Tracking east, the system struggled to develop within a highly sheared environment.[2] By December 29, the system was centered roughly 230 km (145 mi) northeast of Pago Pago, American Samoa, and had developed a low-level circulation accompanied by persistent convection.[3] Development hastened throughout the day, with banding features forming and upper-level outflow becoming established over the system.[4] The system soon acquired gale-force and the FMS upgraded the system to a tropical depression at 21:00 UTC.[5]

Ula moved to the south and eventually west as the system intensified. By January 2, Ula had attained hurricane strength as the storm was upgraded into a Category 2 Tropical Cyclone. Ula has subsequently attained a preliminary peak intensity at Category 3 tropical cyclone status, equivalent to Category 2 hurricane status. Ula weakened afterwards, only to re-intensify to category 3 status again the next day. By January 7, however, Ula turned northwest, slowed and dropped to tropical cyclone status. With the unfavorable conditions, Ula remained at that status for three days. On January 10, Ula rapidly re-intensified to a peak intensity of 115 mph (ten-minute sustained) or 140 mph (one-minute sustained) winds. This constituted as peak intensity and Ula was upgraded to category 4 severe tropical cyclone status, and the Joint Typhoon Warning Center upgraded Ula to a category 4 cyclone. Ula kept category 4 status for 24 hours before an abrupt weakening to a tropical depression. By 12:00 UTC on January 12, Ula transitioned into an extratropical cyclone.[6]

Preparations and impact

Tuvalu and American Samoa

Cyclone Ula near Fiji's Lau Islands on January 3

Early in the storm's existence, Ula produced winds up to 100 km/h (62 mph) across Tuvalu, uprooting trees and leaving 40 homes and 10 businesses damaged, some beyond repair[7][8] Thirty families required evacuation.[8] Waves of 3 to 4 m (9.8 to 13.1 ft) also battered the islands, whose highest elevation is only 4.6 m (15 ft).[9] A fisherman went missing in Faleasao, American Samoa, after being swept out to sea by large swells. After 72 hours, fruitless search efforts were called off.[10]

Tonga

On January 1, Tongan Prime Minister ʻAkilisi Pōhiva preemptively declared a state of emergency for the Vavaʻu and Haʻapai islands.[7] Eleven shelters were opened, with 390 seeking refuge in them.[11] Flights across the nation were suspended for the duration of the storm.[12] Strong winds up to 150 km/h (93 mph) downed trees, power lines, and tore roofs from homes, with Vava'u suffering the brunt of the damage.[7] Overall damage was limited, however, and the previously issued state of emergency was lifted on January 6.[13]

Fiji

After brushing Tonga, Fiji's Lau Islands were in the path of Ula. Officials across the small islands advised residents to move to higher ground and seek shelter in sturdy buildings.[14] Boat services across the Yasawa Islands were temporarily suspended.[15] Though the cyclone passed close to a few islands, damage was relatively limited. Corrugated iron roofs were blown off some structures on Ono-i-Lau and Kabara.[16] Two homes were destroyed on Vatoa.[17] Power and water supplies were temporarily disrupted.[18] Crops also sustained significant damage,[16] with 50 percent lost across the Lau Islands,[19] prompting the Fijian Government to provide a month's-worth of food rations to residents across 13 villages.[20] General relief supplies, including disaster kits, medicine, and water purifying tablets, were also distributed to Ono-i-Lau, Ogea, Fulaga and Kabara.[21] The cyclone's outer bands caused flooding in northern provinces, including Ba.[22] Rainfall was largely beneficial to the nation, particularly for the Western Division, which was in the midst of a drought.[23]

Vanuatu and New Caledonia

Vanuatu's southernmost province of Tafea was placed on alert in advance of Ula's approach.[24] The province was devastated by Cyclone Pam in March 2015, but reported to be prepared to endure another storm. Residents were urged to evacuate and fishermen were advised to return to port.[25] The storm ultimately remained far enough away to cause only limited damage,[24] primarily to agriculture on Aneityum and Futuna islands.[26] Alerts were temporarily raised for Maré Island, New Caledonia; Ula eventually passed harmlessly to the east of the island.[24]

See also

Notes

    References

    1. ↑ Derek Wroe; Sam Houston (December 13, 2018). Hurricane Pali (PDF) (Report). Tropical Cyclone Report. Honolulu, Hawaii: Central Pacific Hurricane Center. Retrieved July 4, 2019.
    2. ↑ Tropical Disturbance Summary For area Equator to 25S, 160E to 120W (Report). Fiji Meteorological Service. December 26, 2015. Archived from the original on December 26, 2015. Retrieved January 11, 2016.
    3. ↑ Significant Tropical Weather Advisory for the Western and South Pacific Oceans. Joint Typhoon Warning Center (Report). United States Navy. December 29, 2015. Archived from the original on December 30, 2015. Retrieved January 11, 2016.
    4. ↑ Significant Tropical Weather Advisory for the Western and South Pacific Oceans. Joint Typhoon Warning Center (Report). United States Navy. December 29, 2015. Archived from the original on December 30, 2015. Retrieved January 11, 2016.
    5. ↑ Gale Warning 024 (Report). Fiji Meteorological Service. December 29, 2015. Archived from the original on December 30, 2015. Retrieved January 11, 2016.
    6. ↑ Gale Warning 126 (Report). Meteorological Service of New Zealand Limited. January 12, 2016. Archived from the original on January 12, 2016. Retrieved January 12, 2016.
    7. 1 2 3 "Tonga takes stock after Cyclone Ula creates widespread damage". stuff.co.nz. January 3, 2016. Retrieved January 11, 2016.
    8. 1 2 "Tuvalu recovering but could face new storm". Radio New Zealand International. December 31, 2015. Retrieved January 11, 2016.
    9. ↑ "Tuvalu battered by heavy rains, strong winds as Pacific island nations brace for Cyclone Ula". Australian Broadcasting Corporation. December 31, 2015. Retrieved January 11, 2016.
    10. ↑ "Missing man in American Samoa named". Radio New Zealand International. January 6, 2016. Retrieved January 11, 2016.
    11. ↑ "No casualties in Vava'u after TC Ula". Matangi Tonga. Nuku'alofa, Tonga. January 2, 2016. Retrieved January 11, 2016.
    12. ↑ "Local MP says Tonga escapes major damage from Ula". Radio New Zealand. January 2, 2016. Retrieved January 11, 2016.
    13. ↑ "State of Emergency lifted in Tonga after cyclone does little". Radio New Zealand. January 6, 2016. Retrieved January 11, 2016.
    14. ↑ "Fiji's Lau group prepares for Cyclone Ula". Radio New Zealand. January 2, 2016. Retrieved January 11, 2016.
    15. ↑ Repeka Nasiko (January 5, 2016). "Boat services on hold amid strong winds". Fiji Times. Archived from the original on March 4, 2016. Retrieved January 11, 2016.
    16. 1 2 "Cyclone Ula causes minor damage in Fiji". Radio New Zealand. January 4, 2016. Retrieved January 11, 2016.
    17. ↑ Nasik Swami (January 5, 2016). "NDMO: Two houses destroyed in Vatoa". Fiji Times. Archived from the original on March 4, 2016. Retrieved January 11, 2016.
    18. ↑ "Worst over for Fiji's Lau islands". Radio New Zealand. January 4, 2016. Retrieved January 11, 2016.
    19. ↑ "Cyclone damage assessment for Tonga, Niue on alert". Radio New Zealand. February 17, 2016. Retrieved February 17, 2016.
    20. ↑ Keresi Nauwakarawa (January 11, 2016). "Food ration for villages in Lau". Fiji Times. Archived from the original on March 4, 2016. Retrieved January 11, 2016.
    21. ↑ Mere Naleba (January 7, 2016). "Relief supplies". Fiji Times. Archived from the original on March 4, 2016. Retrieved January 11, 2016.
    22. ↑ Shayal Devi (January 8, 2016). "Heavy rain, flash flooding in Sarava". Fiji Times. Archived from the original on March 4, 2016. Retrieved January 11, 2016.
    23. ↑ Shayal Devi (January 8, 2016). "Rain brings relief". Fiji Times. Archived from the original on March 4, 2016. Retrieved January 11, 2016.
    24. 1 2 3 "Vanuatu given all clear as Cyclone Ula moves south". Radio New Zealand. January 11, 2016. Retrieved January 11, 2016.
    25. ↑ "Vanuatu's Tafea province feeling effects of Ula". Radio New Zealand. January 10, 2016. Retrieved January 11, 2016.
    26. ↑ Catherine Graue (January 13, 2016). "Vanuatu communities coping after Cyclone Ula". Pacific Beat. Australian Broadcasting Corporation. Retrieved February 21, 2016.
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