Issued 5 February 2007
Heavy rain eases drought, but deficits remain
During January, rain of tropical origin extended heavy falls across central and parts of eastern and southern Australia. These were sufficient to remove short to medium-term rainfall deficiencies, but much of Queensland, NSW, Victoria and northern Tasmania remain affected by severe deficits. In addition, a few regions in northern Australia have had a poor start to their wet season, with serious short-term deficiencies having developed in patches of the northern NT, Cape York Peninsula and southeast Queensland.
13-month rainfall deficiencies
For the 13-month period from January 2006 to January 2007, serious to severe rainfall deficiencies affected a large part of southeast Queensland centred on about Charleville, much of the southern half of NSW, Victoria, northern and eastern Tasmania, southeastern SA and a coastal strip in WA from Carnarvon to Albany. Record low falls occurred along Tasmania’s north coast as well as in parts of the east of that State. It was also the driest such period on record in the mountainous regions of northeast Victoria and southeast NSW extending into parts of the southwest slopes, central tablelands and central-west, and in a few patches along the southwest coast of WA.
The worst of the deficiencies are likely to remain for some time. For example, if they were to be removed by the end of April, falls over the next three months would need to be in the highest 10% of the historical record over many areas, or at record high levels in some instances. A similar situation exists even if we consider six-month falls (Feb-July).
In comparison with the situation at the end of December, deficits were eased or removed in the southern NT, central and parts of eastern SA, the far west of both Queensland and New South Wales, and western Victoria. However, below average January totals resulted in deficiencies expanding across far East Gippsland and the southern and central NSW coasts.
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.
4-month rainfall deficiencies
For the 4-month period from October to January, serious deficiencies have developed across Cape York Peninsula between Cooktown and Weipa, as well as in a few patches of the northern NT near Roper River and Victoria River Downs. Furthermore, severe short-term deficits have emerged in the coastal zone between St Lawrence and Brisbane as well as over the Darling Downs, with record low falls for the period near Goondiwindi.
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