The Winter Storms of June 1967

TROPICAL CYCLONES

Tropical cyclones are possibly the most feared of the weather phenomena to affect Australia. From the earliest days of settlement in tropical Australia, their destructive winds, torrential rains, storm surges, and wild seas have inflicted a heavy toll on communities and travellers in their paths. As they move into higher latitudes or track inland, they lose contact with the warm tropical oceans necessary to sustain them, and weaken; but even weakening storms can be highly disruptive, flooding the inland and buffeting communities.

A maritime peril
Cyclones’ chief fury are expended over the tropical coastal regions and adjacent oceans. The worst ever cyclone-related disaster in Australia’s history occurred in March 1899, when over 300 people were killed in what became known as the Bathurst Bay Hurricane. Early in the 20th century, cyclones extracted a heavy toll at sea, as large vessels were lost with all on board. But while cyclones will always have the potential to take lives, heavy death tolls are now less likely in Australia thanks to the watchful eye of satellites, and enhanced warning and communication capabilities.

“The circuitous route of the cyclone of February/March 1956. This cyclone affected the Australian mainland for 17 days, traversing virtually the whole Western Australian coastline.”

Cyclone definition and frequency
A "tropical cyclone" is a tropical low pressure system intense enough to produce sustained gale force winds (at least 63 km/h). A "severe tropical cyclone" produces sustained hurricane force winds (at least 118 km/h), and corresponds to the hurricanes or typhoons of other parts of the world. In the average cyclone season, 10 tropical cyclones develop over Australian waters, of which six cross the coast, mostly over northwest Australia (between Exmouth and Broome), and northeast Queensland (between about Mossman and Maryborough).

Map showing average annual frequency of tropical cyclones in the Australian region. (courtesy of Jon Gill, Bureau of Meteorology)

Naming the beast
The practice of naming cyclones, first introduced by the colourful Queensland Government Meteorologist Clement Wragge in the late 19th Century, lapsed with his retirement in 1902, but was re-introduced by the Bureau of Meteorology in 1963. Initially, cyclones were given female names, but in keeping with the spirit of "equal opportunity" that emerged in the 1970s, Australian cyclones were allocated both male and female names from 1975.

East coast lows
Some low pressure systems outside the tropics can match tropical cyclones in strength and destructive power. One type, so-called "east coast lows", develop near the coast between southern Queensland and Tasmania, mainly between autumn and spring. These systems can intensify very rapidly, and are capable of generating violent gales, in some cases approaching hurricane intensity. One powerful system in June 1967 caused extensive erosion of Gold Coast beaches. Drawing moisture from the relatively warm Tasman Sea, these systems can also produce intense, flooding rains; a noteworthy example being the storm that brought Sydney to a standstill in August 1986.

“Synoptic chart for the storms of late June 1967. The tight gradient indicates very strong winds; the long “fetch” of these strong winds across the oceans off eastern Australia resulted in huge swells that greatly damaged Gold Coast beaches.”

cyclone | storm | drought | flip side | flood | temperature | fire