The Eastern Seaboard (ESB) of Australia is a distinct climate entity, with little relationship between rainfall in this area and the major drivers of rainfall elsewhere in Australia such as the El Niño-Southern Oscillation (ENSO). One potential cause is the influence of East Coast Lows (ECLs), major coastal weather systems that can produce a significant proportion of rainfall in this region. In this article, a novel approach is used to separate the ECL component of rainfall on the ESB from other sources of rainfall. This method is used to quantify the influence of ECLs on rainfall in this region, with ECLs responsible for 23% of rainfall in the ESB and 40% of widespread heavy rain events. While ECLs are particularly important in the southern ESB and during the cool season (May-October) they can occur in any month, particularly in northern areas of the ESB. ECLs are identified as a significant factor in the weakened relationship between ENSO and rainfall in the ESB, particularly in southern parts; however, these are not the only factor, with local topographic effects also likely to play a role.

The strong relationship between eastern Australian winter–spring rainfall and tropical modes of variability such as the El Niño–Southern Oscillation (ENSO) does not extend to the heavily populated coastal strip east of the Great Dividing Range in southeast Australia, where correlations between rainfall and Niño-3.4 are insignificant during June–October. The Indian Ocean dipole (IOD) is found to have a strong influence on zonal wind flow during the winter and spring months, with positive IOD increasing both onshore winds and rainfall over the coastal strip, while decreasing rainfall elsewhere in southeast Australia. The IOD thus opposes the influence of ENSO over the coastal strip, and this is shown to be the primary cause of the breakdown of the ENSO–rainfall relationship in this region.

East Coast Lows (ECL), strong low pressure systems off the east coast of Australia, can cause severe rain and flooding in this highly-populated region, in addition to strong winds, heavy seas and coastal erosion. While some databases of such events have been previously compiled, this paper discusses a new database developed using an objective low tracking scheme and MSLP reanalysis data between 1950 and 2008, which can be maintained and updated with relative ease on an ongoing basis. The database is verified in comparison to previous subjective ECL analyses, with a particular focus on detection of ECLs associated with significant wind and rain events, and used to develop a climatology of ECLs between 1950 and 2008.

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East Coast Lows are an important weather system that can produce severe wind, wave and rainfall events along the eastern seaboard of Australia. While a number of databases of these systems have been produced, this information has historically not been readily accessible to potential users outside the research sec-tor. This paper details the development of a new product, Maps and Tables of Climate Hazards on the Eastern Seaboard (MATCHES), that bridges this gap. It combines a new database of East Coast Lows with weather impacts across the eastern seaboard. Through use of user-defined impacts thresholds and an intuitive front-end interface, this new tool provides an easy way to link East Coast Lows with their weather impacts.