Severe Tropical Cyclone Gabrielle was a severe tropical cyclone that devastated parts of the North Island of New Zealand and affected parts of Vanuatu and Australia in February 2023. It is the costliest tropical cyclone on record in the Southern Hemisphere, with total damages estimated to be at least NZ$13.5 billion (US$8.4 billion), of which the cost of insured damage is at least NZ$1.65 billion (US$975 million). The total cost in the Hastings District alone is estimated to surpass NZ$2 billion (US$1.25 billion). It was also the deadliest cyclone and weather event overall to hit New Zealand since Cyclone Giselle in 1968, surpassing Cyclone Bola in 1988. The fifth named storm of the 2022–23 Australian region cyclone season, and the first severe tropical cyclone of the 2022–23 South Pacific cyclone season, Gabrielle was first noted as a developing tropical low on 6 February 2023, while it was located on the south of the Solomon Islands, before it was classified as a tropical cyclone and named Gabrielle by the Bureau of Meteorology. The system peaked as a Category 3 severe tropical cyclone before moving into the South Pacific basin, then rapidly degenerated into a subtropical low on 11 February 2023.
Norfolk Island was placed under a red alert as Gabrielle approached, while heavy rain and wind warnings were issued across the North Island of New Zealand. Existing states of emergency in Auckland and the Coromandel due to recent floods were extended, and new states of emergency were declared in other areas. The cyclone impacted New Zealand from 11 to 17 February, with a national state of emergency being declared on 14 February 2023. All states of emergency had been lifted by 14 March.
Meteorological history
On 5 February, the Australian Bureau of Meteorology (BoM) reported that Tropical Low 14U had developed within a monsoonal trough of low pressure over the northeastern Coral Sea, about to the southeast of Honiara in the Solomon Islands. During that day, the system passed near or over Rennell Island in the Solomon Islands as it moved westwards into the Australian region from the South Pacific basin. At this stage, the system was located within a favourable environment for further development with low vertical wind shear of and warm sea surface temperatures of . Over the next couple of days, the system gradually developed further as it moved south-westwards along a ridge of high pressure towards Queensland, Australia, before the United States Joint Typhoon Warning Center initiated advisories and classified it as Tropical Cyclone 12P during 8 February. At around the same time, the BoM reported that the tropical low had developed into a Category 1 tropical cyclone on the Australian tropical cyclone intensity scale and named it Gabrielle.
Gabrielle slowly drifted southwards while deep convection consolidated, and the cyclone was upgraded into a Category 2 tropical cyclone, while the JTWC upgraded Gabrielle to the equivalent of a low-end Category 1-equivalent cyclone with winds of . By 18:00 UTC on 9 February, the storm continued to intensify and soon became a Category 3 severe tropical cyclone. During 10 February as Gabrielle moved back into the South Pacific basin, the BoM reported that Gabrielle had peaked as a Category 3 severe tropical cyclone with 10-minute sustained windspeeds of . Gabrielle began to experience an increase in northwesterly vertical wind shear, the JTWC downgraded it to a Category 1-equivalent cyclone. On 10 February, Gabrielle moved into MetService's area of responsibility. The JTWC also discontinued warnings on the system around 21:00 UTC that day Gabrielle was downgraded to a Category 2 tropical cyclone by the MetService. During 11 February, after Gabrielle had passed directly over Norfolk Island, the BoM and MetService reported that Gabrielle had weakened into a deep subtropical low.
Effects
Melanesia
In Vanuatu, Malpoi, a village in the northwest of Espiritu Santo, was severely affected by landslides, mud, and the destruction of houses and gardens. The water supply was also contaminated. As their plantations were damaged by the landslide, chairman Allan Taman of Vanuatu's Santo Sunset Environment Network stated that the villagers may require long-term financial assistance. Some villagers in the disaster-affected areas were also forced to evacuate. In New Caledonia, strong swell warnings were put in place for 16 districts; 14 boats were damaged and one sank due to wind and swells, leading to an evacuation plan for the damaged ships.