Cyclone Yali

Severe Tropical Cyclone Yali

Category 3 cyclone (Australian scale) Category 2 Tropical Cyclone (SSHWS)
Severe Tropical Cyclone Yali
Formed	March 18, 1998
Dissipated	March 27, 1998
Highest winds	10-minute sustained: 130 km/h (80 mph) 1-minute sustained: 165 km/h (105 mph)
Lowest pressure	965 mbar (hPa); 28.5 inHg
Fatalities	1 total
Damage	Minimal
Areas affected	Vanuatu, New Caledonia, New Zealand
Part of the 1997–98 South Pacific and the Australian region cyclone season

Cyclone Yali was one of seven severe tropical cyclones to develop during the 1997–98 South Pacific cyclone season. First forming on March 18, Yali gradually intensified under favorable conditions. Moving southwest, the storm attained hurricane-force winds on March 22. The next day, Yali attained peak intensity as a Category 3 cyclone on the Australian intensity scale. After turning towards the southeast, Yali began to weaken. By March 27, it had lost tropical characteristics, though the remnants were still tracked for a couple more days. Through its life, Yali posed a threat to several land masses. In its formative stage, Cyclone Yali brought flooding and extreme crop damage to Vanuatu. After brushing New Caledonia and Vanautu near peak intensity, the extratropical remnants of Severe Tropical Cyclone Yali brought effects to New Zealand. One person was killed and widespread power outages and damage were reported.

Meteorological history

Early on March 17, 1998, the United States Joint Typhoon Warning Centre started to monitor a tropical disturbance that had developed about 750 km (465 mi) to the northeast of Port Vila, Vanuatu.^[1] During that day convection over the low level circulation centre organized further before the JTWC issued a tropical cyclone formation alert on the system later that day.^[2] As the system quickly developed further the Fiji Meteorological Service's Nadi Regional Specialized Meteorological Centre (RSMC Nadi) subsequently started to monitor the system as a well defined area of low pressure early the next day.^[3][4]

At 1800 UTC March 19, Nadi remarked that the low had deepened into a Category 1 cyclone on the Australian intensity scale and was thus named Yali. Initially moving southwest, Tropical Cyclone Yali turned southeast in response to a strengthening monsoonal flow.^[4] Simultaneously, the JTWC announced that the storm had attained winds of 50 mph (80 km/h). Given the fact that Yali was in a region of warm sea surface temperatures and low wind shear, the agency predicted that the storm would intensify to a high-end Category 2 hurricane on the Saffir-Simpson Hurricane Scale.^[5] After passing west of Vanatu, this storm gradually intensified;^[4] by March 21, the JTWC reported that Yali had intensified into a Category 1 hurricane.^[5] The following day, Nadi estimated that Yali had become a Category 3 cyclone on the Australian intensity scale. Very early on March 22, Yali passed within 60 mi (95 km) west of Port Vila the next day. According to RMSC Nadi, Yali attained peak intensity of 80 mph (130 km/h) and a pressure of 965 mbar (28.5 inHg).^[4] Meanwhile, the JTWC reported that winds had attained 110 mph (175 km/h).^[5]

Shortly after its peak, thunderstorm activity began to decrease, and Yali started weakening. On March 22, the JTWC noted that winds had subsided to tropical storm status^[5] while winds soon dropped below Category 2 intensity.^[6] At around the same time, a mid-level subtropical ridge began to influence its motion, sending it to the west. As Yali moved to the southwest, the wind field became asymmetric. Based on Nadi data, by March 23, Yali was just east of Noumea, New Caledonia with winds of 50 mph (80 km/h). After passing south of New Caledonia, an upper-level low picked up the cyclone and induced cold air into the atmospheric circulation.^[4]

RMSC Nadi downgraded Yali into an extratropical cyclone and thus stopped issuing advisories. However, the JTWC continued to track it as it moved towards Australia, its remnants moving to the west and crossing 160°E on March 25. By the next day, Yali's center was less than 300 mi (480 km) east-northeast of Brisbane, Australia. Despite a brief revival of convection, on the morning of March 27, the JTWC released its final bulletin on Yali. At this time, the low was located around 300 mi (480 km) east-southeast of Brisbane. The remnants of Yali went under a transformation in the Tasman Sea and respectively deepened south of New Zealand. After passing the country and later the Antarctic Circle, the system merged with a trough.^[4]

Preparations, impact, and aftermath

Vanuatu

While Yali passed west of the Vanatu Islands, it came close enough to affect the isles of Tanna and Aneityum. Tanna saw about 60–70% of its crops destroyed and about 30% of its homes damaged by the storm.^[4] In Banana, vegetables and manioc crops, as well as fruit trees were entirely destroyed. In the atoll island of Aniwa, minor damage to houses and agriculture has been reported.^[7] Other places in Vanatu only received minor damage,^[4] though Yali caused heavy rainfall and flooding throughout the island group and affected residents in low-lying areas and close to river banks. Throughout the county, some damage was recorded to local buildings and banana plantations were destroyed. During the aftermath of the storm, several evacuation centers were opened on the mainland to victims who had left their homes during the storm. The Government of Vanuatu sought support from the local Red Cross and other relief groups.^[7] At peak intensity, Yali brushed Port Vila with 15 mph (24 km/h) winds (perhaps due to poor exposure of the instrument) and a peak pressure of 992 mbar (29.3 inHg).^[4]

New Caledonia

Between March 23 - 24, Cyclone Yali affected Southern New Caledonia, the Loyalty Islands and the Isle of Pines, as it passed just to the south of French Territory.^[3][8] Within the island nation some damage was reported with roofs of houses and trees uprooted.^[8] The Isle of Pines recorded a rainfall total of 137 mm (5 in) while wind gusts of 162 km/h (101 mph), 126 km/h (78 mph) and 101 km/h (63 mph) were reported in Cape N'Dua, Isle of Pines and La Roche.^[8]

New Zealand

Upon striking New Zealand as an extratropical storm, it caused high seas and flooding over South Island, Westport and Nelson.^[4] One fatality occurred when a youth was swept away into the ocean in New Plymouth.^[9] Trees were toppled, roofs were ripped off and power lines fell.^[4] In addition, another person had to be rescued in Waikato. Because of high winds, trees were downed, trucks were blown across roads, and buildings were left without roofs. Yali also caused air travel difficulties in Wellington,^[10] where a car was hit by a flying billboard. Tararuas recorded rainfall totals exceeding 4 in (100 mm). In addition, trees blown over by gales closed a major route between Nelson and Picton. High winds blew a roof in Hataitai. In Paraparaumu and Waikanae, a sudden period of heavy rain led to flooded basements. Due to a combination of rough seas and a high tide, a bay was flooded. Many inland roads became difficult to drive on and widespread power outages were reported. In all, only minor flooding was reported; the primary threat of Yali was high winds, not heavy rain. Due to the storm's rapid motion, the bulk of the rainfall fell within 12 hours.^[9]

See also

• Cyclone Les (1998)

References

External links

• World Meteorological Organization
• Fiji Meteorological Service
• Meteorological Service of New Zealand
• Joint Typhoon Warning Center

v t e Tropical cyclones of the 1997–98 South Pacific cyclone season 2 Lusi TD 03P 3 Martin 2 Nute 3 Osea 2 Pam 5 Susan 5 Ron 3 Katrina–Victor–Cindy 1 Tui 2 Ursula 2 Veli 2 Wes TD Unnamed TD Unnamed TD Unnamed 3 Yali 3 Zuman 1 Alan 1 Bart Book · Category · Portal · WikiProject · Commons