BAMOS Vol 31 No.2 June 2018 | Page 24

24 BAMOS Jun 2018 Charts of the Past with Blair Trewin 7 June 1954 The autumn of 1954 was a very dry period in much of southeastern Australia, something of an aberration in the very wet 1950–1956 period (including severe flooding in February 1954 on the north coast of New South Wales from a nearby cyclone). It was the fourth-driest autumn on record in New South Wales. A breakdown in this dry pattern came in the first week of June as a trough developed on the 3rd over inland Queensland and New South Wales and moved slowly to the east. Widespread rain fell on the 4th and 5th in the eastern inland, including 82 mm at Caiwarro, near Hungerford, on the 4th, and 71 mm at Hungerford itself on the 5th. Locally heavy falls also occurred closer to the coast as a low formed over eastern New South Wales on the 4th, with 94 mm at Stroud and 81 mm at Forster on the 5th. The generally light to moderate falls in inland New South Wales, including weekly totals of 25 to 50 mm over most of the grain belt, were agriculturally useful, although the winter ultimately proved also to be drier than average with consistent above-average totals not occurring until October. The low moved offshore on the 5th and then intensified rapidly as it moved southeast, before becoming near-stationary east of Tasmania on the 6th. This directed a moist southeast flow into Tasmania, leading to extremely heavy rainfall over the next two days in much of eastern Tasmania. The heaviest falls were in the Hobart area, with 215.9 mm at Kingston and 201.4 mm at the Hobart Waterworks Reserve on the 7th, but heavy rain also extended north along the east coast, with daily totals in excess of 100 mm extending north to St Helens, and 177.3 mm at St Marys. The Springs, on the slopes of Mount Wellington, had 311.1 mm over two days. Hobart city received 147.3 mm on the 7th, its second-wettest day on record, whilst the two-day total of 190.2 mm was a record. Records were also set at every timescale from three to seven days, and June 1954 went on to be Hobart’s third-wettest month on record with 238.3 mm. The heavy rains led to significant flash flooding in and around Hobart, with damage in the central city alone running to hundreds of thousands of pounds as the Hobart Rivulet reached its second-highest level on record (at the time). Water was 60 centimetres deep in City Hall. Flooding also affected other parts of the state; the far south of the state was cut off after a bridge over the Esperance River was washed out, and the Macquarie River at Ross also experienced major flooding. There were several substantial landslides in the Huon and Channel areas. One person died when they fell from a broken swing bridge into the swollen Derwent River. Power was lost to the entire state for a time, and phone services were also disrupted, whilst there was significant disruption to coastal shipping in high winds off the east coast. The low moved east on the 8th, with the rain clearing from eastern Tasmania. Falls continued in east Gippsland, with Cabbage Tree Creek ultimately receiving 141 mm over the two days to the 8th, although with dry antecedent conditions there was no significant flooding. Temperatures during the event were below average but not exceptionally so, with maxima on the 7th including 9.7 °C at Hobart, 8.6 °C at Canberra and 10.7 °C at Melbourne (which missed most of the rain, receiving just 12 mm over three days); snow fell on higher ground in the Alps and the Monaro, including 15 centimetres at Nimmitabel. On the other side of the continent, a blocking high over Western Australia brought a prolonged period of dry and cool weather to the southwest, including sequences of seven consecutive sub-zero nights at Bridgetown (a June record) and eight at Wandering. Synoptic chart for 1200 AEST, 7 June 1954