Tropical cyclones in the South Pacific: impacts on island communities

Impacts on island communities

Tropical cyclones produce extreme weather conditions over warm oceans, and can be particularly damaging for small Pacific islands. But their physical effects are not all destructive. This article describes how such storms form, looks at their negative and positive impacts and considers how climate change may affect their nature. It is relevant to topics on hazards and climate

James P. Terry

A flood in the Sigatoka River in Fiji during Cyclone Mick in December 2009 has pushed vegetation debris high up against the old bridge (now broken and abandoned) near Sigatoka town

Tropical storms are called cyclones in the South Pacific (Table 1), hurricanes in the North Atlantic and typhoons in the North Pacific oceans. They are intense low-pressure systems that form in tropical latitudes, mostly between 5° and 20°, where warm ocean waters (above 26.5°C) extend over a large area. The initiation and development of a cyclone is called tropical cyclogenesis.

To begin with, a low-pressure cell forms by convection caused by the thermal imbalance between the warm tropical ocean and the cool upper atmosphere. Moist air is drawn inwards as convection intensifies and strong winds are generated, converging into the centre. The warm ocean provides heat and moisture to fuel the system.