Issued 4 December 2006
Drought intensifies over eastern and southern Australia
rainfall deficiencies have been gradually spreading over eastern and southern Australia during 2006, but the situation has taken a distinct turn for the worse from August, with a near total failure of the late-winter and spring rains. In the historical record dating from 1900, it was the driest August to November period averaged across SA, the second driest averaged over the Murray Darling Basin, the third driest across Australia and the fourth driest for Victoria. Rainfall deficits have also developed over parts of the tropics as evidence of a poor start to the northern wet season.
It has also been remarkably warm over this period as well, with mean maximum temperatures being the highest on record (for the post-1950 era) averaged over Australia, Victoria, SA, WA and the Murray Darling Basin. Over NSW and the NT maximum temperatures were the second highest on record.
Rainfall deficits are also evident over other agriculturally sensitive periods during 2006: the period since May has been very dry across much of southern and western WA (as well as in the southeast of the country), while for the period beginning in January, southeastern Australia (including Tasmania), southeast Queensland and a coastal strip in southwest WA are affected by severe rainfall deficiencies.
4-month rainfall deficiencies
For the 4-month period from August to November, generally severe rainfall deficiencies covered most of the southern two-thirds of SA, all of Victoria, northern and eastern Tasmania, most of NSW west of a line from Bega to Tamworth to Bourke, much of Queensland’s western half, pockets along the south coast of WA and large areas in the northern half of the NT. Significant regions have had their driest August to November on record - especially over central SA extending into the far northwest of NSW and far southwest of Queensland, and also the tablelands and western slopes between the ACT and Dubbo in NSW. Record low totals also occurred around Esperance in southern WA.
7-month rainfall deficiencies
For the 7-month period from May to November, severe rainfall deficiencies cover most of western and southern WA, although average to above average rainfall during November caused a modest decrease in the extent and intensity of the deficits in comparison with the situation at the end of October. Also experiencing deficits for this period are SA southeast of a line from Ceduna to Marree, Victoria (apart from East Gippsland), much of NSW west of the Divide and south of about Tamworth, the southeast inland of Queensland centred on about Miles, and northern and eastern Tasmania. Numerous small regions, mainly near the coast, have registered record low totals for this period.
11-month rainfall deficiencies
Since the start of the year, i.e. the 11-month period from January to November, serious to severe rainfall deficiencies affect southeast Queensland away from the coast, much of the southern half of NSW west of the ranges, Victoria (apart from far East Gippsland), northern and eastern Tasmania, southeastern SA and a coastal strip in WA from Carnarvon to Albany. In addition, parts of the interior between Bourke and Alice Springs also have deficiencies for this period. Record low falls are analysed along Tasmania’s north coast and in the mountainous regions of northeast Victoria and southeast NSW, extending into parts of the southwest slopes.
The deficiencies discussed above have occurred against a backdrop of multi-year rainfall deficits that have severely stressed water supplies in the east and southwest of the country.
Lowest on record - lowest in the historical analysis, which runs from 1900.
Severe deficiency - rainfalls in the lowest 5% of historical totals.
Serious deficiency - rainfalls in the lowest 10% of historical totals, but not in the lowest 5%.
Very much below average - rainfalls in the lowest 10% of historical totals.
Below average - rainfalls in the lowest 30% of historical totals, but not in the lowest 10%.
Average - rainfalls in the middle 40% of historical totals.
Above average - rainfalls in the highest 30% of historical totals, but not in the highest 10%.
Very much above average - rainfalls in the highest 10% of historical totals.
Product Code IDCKGD0AR0