For the 1, 8 and 13-year periods ending 31 March 2010
Issued on 8 April 2010
Short-term deficiencies eased in east but long-term rainfall deficits remain
Above average rainfall continued across eastern Australia during March 2010. For the Murray-Darling Basin (MDB) averaged as a whole, it has been the seventh wettest start to the year since records began in 1900, while Victoria has had its wettest start to the year since 1974. While recent rainfall has cleared a number of short-term rainfall deficiencies across eastern Australia, on time-scales longer than two years, serious deficiencies remain, and to alleviate these would require above average rainfall for a sustained period. This is especially true for the very long-term deficiency periods of 8 and 13 years. Rainfall has been below average across much of southwest and southeast Australia since 1997, whilst central and southern parts of the MDB have experienced below average rainfall since 2002.
12-month rainfall deficiencies
Above average falls along the southwestern WA coast in March 2010 generally missed the areas of greatest rainfall deficiency described in the previous drought statement. For the 12-month period from April 2009 to March 2010, serious to severe rainfall deficiencies remain evident over much of the central WA coast reaching inland, covering much of the Pilbara and Gascoyne districts, where they have intensified to some extent. Serious to severe rainfall deficiencies also remain evident over the Southeast Coastal and Great Southern districts, with a small area of lowest-on- record for the period located near Esperance.
8-year rainfall deficiencies
For the 8-year period from April 2002 to March 2010 (96 months), much of southeastern Australia is covered by severe rainfall deficiencies. Around 95% of Victoria has received rainfall in the lowest 10% of historical totals when considered over such a time period. The southeastern corner of Queensland is also covered by serious to severe rainfall deficiencies when considered over this time period; recent rains have not been enough to remove deficiencies. Serious to severe deficiencies also remain in central to eastern coastal districts of SA, large areas of Tasmania, especially in the north, and in a large area covering the southwest coast and adjacent inland regions of WA.
13-year rainfall deficiencies
The 13-year period from April 1997 to March 2010 (156 months) shows rainfall deficiencies covering much of the same area, but less of the central parts of the MDB. Most notable are the large areas of lowest on record for this period: large parts of the WA southwestern coast, western Tasmania, and large areas in Victoria received lowest on record rainfall for the 13-year period.
Whilst recent rains in eastern Australia have provided, in many cases, short-term relief, sustained periods of above-average rainfall are needed to remove these very long-term deficiencies. These long-term deficiencies have taken place against a background of well above average temperatures including Australia's warmest decade on record. Further information on exceptional rainfall and temperature events across Australia can be found in the Special Climate Statements.
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