BETSY

History

Severe Tropical Cyclone Betsy was a long-lived system that affected several Pacific island nations in January 1992. Its origins lay in an equatorial westerly wind burst in early January, which strengthened low-level westerly flow on the northern flank of the Southern Hemisphere monsoon trough east of New Guinea. Convection associated with the burst gradually organised, and late on 5 January a tropical depression formed within the monsoon trough west of Tuvalu. The Joint Typhoon Warning Center began issuing advisories early on 6 January, designating the westward-moving system Tropical Cyclone 11P. With a steadily more symmetrical cloud pattern, strong upper-level outflow and weak vertical wind shear, the depression reached category 1 intensity, and the Fiji Meteorological Service named it Betsy late on 6 January.

Betsy then took an erratic south-southeasterly course as it interacted with a mid-level trough. It intensified further on 7 January beneath a strong upper-level anticyclone to its north and developed an eye, passing roughly 95 km east of Anuta in the Solomon Islands, where an automatic weather station recorded winds of 85–100 km/h, and about 160 km east of Tikopia. A ridge building to the southeast and upper-level easterlies turned the cyclone onto a south-southwesterly track. Betsy reached severe tropical cyclone status, category 3 on the Australian scale, during 8 January, its peak intensity.

The cyclone crossed central Vanuatu early on 9 January, with the eye passing over or very near Ambrym and Malakula between 00:00 and 05:00 UTC. Vanuatu was the worst affected country, experiencing gale, storm and hurricane-force winds between 7 and 9 January. On 10 January the Vanuatu Government formally requested international assistance; a French Gardian and an Australian Orion conducted aerial damage surveys the following day, ahead of a donor meeting on 12 January. Betsy then affected New Caledonia on 9–10 January, passing about 195 km north of the Belep Islands, with gales reaching as far south as Nouméa. Heavy swell caused flooding and minor damage in northern Tuvalu, while squally westerlies around Kiribati and Nauru were blamed for five deaths.

Sources: Bureau of Meteorology report Wikipedia