BAMOS Vol 31 No.3 September 2018 | Page 20

20 BAMOS Sep 2018 Charts of the Past with Blair Trewin 28 May 2000 Major low-elevation snowfalls have become rare in Australia in recent decades. One of the most notable events in the last 30 years—particularly so early in the cool season—occurred in late May 2000. A low-pressure system formed west of Tasmania on 26 May, then moved slowly southeast to be just south of Tasmania on the 28th. It then continued to drift slowly southeast into the Tasman. With strong high pressure to the west, southeast Australia was placed into a long-lived southwesterly airstream, particularly after a front crossed Victoria early on the 28th; not until 3 June did the flow ease. Cold air initially reached mainland Australia on the 26th. On the 27th the most significant cold occurred in South Australia, with light snowfalls on the higher parts of the Mount Lofty Ranges and Flinders Ranges, and record low May maximum temperatures at Clare and Mount Barker. This was also the coldest day of the event at Melbourne (with a maximum of 10.2 °C, the lowest in May since 1977), and in parts of the southeast inland, including a May record 8.0 °C at Deniliquin. The most significant part of the event occurred on the 28th. As the cold front crossed Victoria, snow fell to very low levels in places, particularly in areas north and east of Melbourne. Significant snow occurred as low as 250-300 metres in areas such as the upper Goulburn Valley around Alexandra and Yea, and in the state’s northeast, whilst light falling snow was observed in Melbourne suburbs. 30 centimetres of snow fell at Beechworth, the heaviest fall there in more than 30 years. With heavy snowfalls in areas which rarely experience them, falling trees were a major hazard, with two deaths reported. High winds also accompanied the cold, with gusts of 132 km/h at Mount Buller and 124 km/h at Fawkner Beacon in Port Phillip. During the day the snow extended to the New South Wales highlands. In Canberra, it was the heaviest snowfall since at least 1987 (and the last time to date that substantial snow has settled in the central city); the NRL match between the Raiders and the Wests Tigers was played in the snow. Low-level snow also extended into the Central Tablelands. The 28th was an especially cold day at higher elevations. The three lowest May maximum temperatures on record for Australia were set, led by −6.0 °C at Thredbo Top Station and −5.6 °C at Mount Hotham. Hunters Hill, at 980 m elevation west of Corryong, had its only sub-freezing maximum (−0.7 °C) in 26 years of data, whilst Canberra’s 4.3 °C was a May record and its coldest day in any month since 1966. At low elevations in southern New South Wales, temperatures generally fell short of the records set in 1977, the only comparable May event in recent decades. Whilst the most significant snowfalls ended on the 28th, the cold only moderated slightly, and in places the 30th was the coldest day of the whole event (including a May record of 4.6 °C at Bathurst). By then, deep southerly flow had pushed cold air far into northern Australia, with widespread frosts across Queensland which continued into early June. Frosts on 2–3 June on the Atherton Tableland were the most significant since 1984, with major crop damage. It failed to reach 30 °C anywhere in Australia in the six days from 30 May to 4 June, a sequence unprecedented in at least the last 60 years. Whilst heavy rainfall was not the event’s most notable feature, substantial falls still occurred in much of the southeast. Totals from 27–31 May were generally 50–100 mm in western Tasmania and over the ranges in Victoria (locally exceeding 100 mm in the Yarra Ranges), 25–50 mm in southern Victoria and southeast South Australia, and 10–25 mm ov