Links between the Southern Oscillation Index and Hydrological Hazards on a Tropical Pacific Island

River floods and hydrological droughts (low stream water resources) are a recurrent problem in different parts of Fiji, causing disruption and hardship for many rural communities. These extremes in fluvial behavior are associated with large seasonal variability in rainfall, generated by intense tropical storms in the wet season and prolonged rain failure in the dry season. Such conditions are linked to the influence of El Nino/Southern Oscillation (ENSO) in the Southwest Pacific. The Southern Oscillation Index (SOI) is the climatic measure of the strength of ENSO activities and shows good correspondence with (1) tropical cyclone flood magnitude and (2) critically low stream discharges after a 2-month time lag, in two of Fiji's main river systems. If ENSO conditions become more frequent or sustained in the future as some climate models suggest, then the SOI will be a useful tool for projecting in advance the severity of hydrological hazards, which can assist in disaster mitigation and management