Summary
Tropical Cyclone Esau was the fourth cyclone to affect the Vanuatu group during the 1991-92 season, closely following Daman a week and a half earlier. Esau was also the second cyclone to affect the Solomon Islands.
Tropical cyclone Esau developed from a shal- low depression which formed about 370 km northeast of northern Vanuatu on 24 February. The depression was part of an active monsoon trough extending from northern Australia through Vanuatu and eastwards to Samoa.
The system initially drifted southwestward towards northern Vanuatu under the influence of a northeasterly steering flow, making a clockwise loop over the island of Espiiitu Santo as it under went further organisation. Tropical cyclone Esau was named at 0700 UTC 26 February whilst located just east of Espiritu Santo, and by 1800 it had moved southwest, clear of the Vanuatu group.
Esau then accelerated on a westward track on the northern side of an intense subtropical ridge. With decreasing vertical shear, the cyclone intensified at a steady rate; by 28 February sustained winds had reached hurricane force near the centre, which was located about 550 km west of Espiritu Santo. Between 1800 UTC 28 February and 1200 UTC 29 February, the system attained peak intensity of 50 m/s and executed a second, larger, clockwise loop. At this stage in its development, Esau exhibited a distinctly symmetrical cloud signature with a well-defined eye. At the northern most point of its trajectory,
Esau was about 260 km south of Bellona and Rennell Islands in the Solomon group and these islands were within the estimated radius of gale-force winds.
From 1 March, tropical cyclone Esau started to move steadily southeastwards and weaken under the influence of a northwest steering flow ahead of a developing upper trough. The system moved away from the Solomon Islands and returned to within 450 km of southern Vanuatu on 4 March before turning south towards New Caledonia. By this stage, the eye had filled with cloud and the overall cloud structure had become distorted. Sustained winds close to the centre were estimated to be 40 m/s when it struck central parts of New Caledonia overnight on 4 March, crossing the coast not far from Ponerihouen. Passage over a mountainous island barrier and increasing verti- cal wind shear combined to further weaken the cyclone. On 5 March, winds decreased below huRricane force as the cloud signature became much less organised and upper clouds became sheared off to the south of the low-level centre. With further southward movement, the system under- went extratropical transition over the cooler waters of the Tasman Sea and eventually passed over the North Island of New Zealand with much reduced intensity.
Tropical cyclone Esau directly affected three countries in its path through the southwest Pacific. Gale-force winds at Bellona and Rennell Islands in the Solomon group destroyed several houses and caused some food crop damage due to flooding. On New Caledonia, which bore the brunt of hurricane-force winds, one woman was drowned. In addition, buildings were damaged and roads blocked.
Track and intensity
