East coast lows

Winter storms

Rain in Sydney

Some of the more intense low pressure systems outside the tropics are capable of matching the power and destructive potential of many tropical cyclones. In a class by themselves in this regard are the class of cyclones known as "east coast lows", which as their name implies, develop near the east coast between southern Queensland and Tasmania. They are most common off New South Wales, where on average one develops each year, in winter or the transition seasons. Such systems can intensify very rapidly (pressure falls of 24 hPa within 24 hours are not uncommon). They are capable of generating violent gales, at their worst approaching hurricane intensity. One powerful system in June 1967 was noteworthy for the extensive erosion of Gold Coast beaches. Drawing moisture from the relatively warm waters of the Tasman Sea, these systems can also produce intense, flooding rains; a noteworthy example was the system that brought Sydney to a standstill in August 1986. East coast lows have in fact been responsible for many of the major flood episodes on east coast river systems - severe flooding in eastern Victoria in June 1998 being a recent example. The systems are a normal part of the climate of eastern Australia, and have been hitting the east coast at least since European settlement. One of the earliest descriptions of an east coast low, in June 1820, can be found in the log book of Captain Phillip King, who charted extensive portions of the Australian coastline between 1818 and 1822.

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