Cyclone Wasa–Arthur

Category 4 South Pacific cyclone in 1991

Severe Tropical Cyclone
Wasa–Arthur
Wasa near its peak intensity on 7 December
Meteorological history
Formed3 December 1991 (1991-12-03)
Dissipated18 December 1991 (1991-12-18)
Category 4 severe tropical cyclone
10-minute sustained (FMS)
Highest winds165 km/h (105 mph)
Lowest pressure940 hPa (mbar); 27.76 inHg
Category 3-equivalent tropical cyclone
1-minute sustained (SSHWS/NPMOC)
Highest winds195 km/h (120 mph)
Overall effects
Fatalities2 confirmed
Damage$60 million (1991 USD)
Areas affectedFrench Polynesia
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Part of the 1991–92 South Pacific cyclone season

Severe Tropical Cyclone Wasa–Arthur was the first major tropical cyclone to affect French Polynesia and Tahiti since the 1982–83 season. The system was first noted on 3 December 1991, as a shallow tropical depression that was embedded within the monsoon trough, to the north of the Cook Island: Rarotonga. Over the next couple of days the system gradually developed further, before it was classified as a tropical cyclone and named Wasa on 5 December. The following day, as it performed a small clockwise loop, the system strengthened further and acquired hurricane-force winds. After completing the loop, Wasa moved southwards before it peaked in intensity during 8 December, with sustained wind speeds of 165 km/h (105 mph). Over the next few days the system started to weaken as it passed through the French Polynesian Society Islands, and became the first major tropical cyclone to affect French Polynesia since 1983.

During 12 December, Wasa passed through the French Polynesian Austral Islands and passed directly over Tubuai, before it degenerated into a tropical depression later that day. However, gale-force winds remained associated with the depression, before the system turned towards the east-northeast and entered into warmer waters near the Tuamotu Islands. On 14 December, Wasa regenerated into a tropical depression and was renamed Arthur. During that day, the system gradually intensified before it reached its secondary peak intensity with sustained wind speeds of 95 km/h (60 mph). The following day, the system maintained its peak intensity, as it moved through the uninhabited Acteon group of islands, before it started gradually weaken the next day. Arthur degenerated into a shallow depression during 17 December, before it was last noted during the next day as it dissipated to the north of the Pitcairn islands.

Tourists on the island of Bora Bora were evacuated to a local church, after Wasa–Arthur had swept high seas into tourist bungalows. Overall the system caused an estimated US$60 million in damage within French Polynesia, with the majority of the damage done between 9 and 12 December. The system destroyed or damaged several homes, a variety of crops and damaged several public buildings, hotels, roads and power installations, with the worst affected islands being Bora Bora and Tubuai. On Rurutu island, Moerai harbour was destroyed by a cyclonic swell generated by the system, while the local school and police station were destroyed by high waves. Two people were killed after torrential rainfall from the system caused a mudslide on the island of Moorea, during a night of torrential rain the day after Wasa had made its closest approach to the island. The French Government incurred costs of about FF68 million including FF53 million for the efforts of the French Military. The French Polynesian Government subsequently borrowed FF55 million and built up a fund from local banks of about FF1.5 billion, to help with the reconstruction. The name Wasa was later retired, from the list of tropical cyclone names by the World Meteorological Organization.

Meteorological history

Map plotting the storm's track and intensity, according to the 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
circle Tropical cyclone
square Subtropical cyclone
triangle Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression