However, an east coast cyclone on 24 and 25 May set in motion a sequence of low pressure systems that produced almost continuous rainfall over southern and western Tasmania that extended occasionally to the rest of the island, especially on the third and fourth of June when falls reached 70 millimetres (2.8 in) for two days in Hobart and 60 millimetres (2.4 in) in Swansea.
These systems produced only localised flooding, but when a strong frontal system that had produced extremely heavy rain in the far south of Western Australia with record daily falls at Manjimup[2] moved rapidly eastwards and intensified, rainfall over Tasmania, which had been consistent ever since the beginning of the month, intensified to the extent of general falls of over 8 inches (200 mm) on the highlands and 3 inches (80 mm) on the southeast coast during the three-day period ending 17 June, a day after the King's Birthday holiday[3] On ground that was already saturated, rivers in the south of Tasmania reached almost unprecedented levels, for instance it is estimated that the Huon reached flows as large as 4,000m3/s,[4] larger than the flow of the Sepik River in New Guinea, whilst the flood on the Derwent was the highest of the twentieth century and not exceeded since at least the 1870s at around 3,500m3/s.
[4][5] At Butler's Gorge, hydroelectric operations were completely washed out[6] and it was notable that without energy for heating in most homes during wet weather with maxima around 10 °C (50 °F) there were no deaths,[6] in part because Lake St. Clair stored enough water to reduce the level of the Derwent by four feet.
[5] Most of southern Tasmania's hop crop was completely lost (replanting was not possible for some time afterwards due to extreme soil erosion in the valley), and it is estimated that over a thousand prime beef cattle drowned in the Huonville district.
Washaways, along with destruction of the state's hydroelectricity infrastructure, meant that only one of the scheduled buses could reach Queenstown from Hobart and it took over a day and a half beyond the usual time to do so.