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For the 8 and 17-month periods ending 31st October 2008
Rainfall deficiencies expand in southeastern Australia
LINKS:
rainfall deficiencies definition
8-month rainfall deficiencies
17-month rainfall deficiencies
Below average October 2008 rainfall over Victoria, Tasmania, SA, southern and
western NSW, southeastern Queensland and the WA interior maintained, and in some cases increased, short and
long-term deficiencies in these areas. This was particularly evident in the short-term in parts of eastern Tasmania and
Victoria, with areas of lowest on record totals increasing.
For the 8-month period from March to October 2008, areas of serious to severe rainfall
deficiencies have persisted over much of Victoria (extending into southern NSW and the far southeast of SA), eastern
Tasmania and central and western SA extending into the WA interior. Below average October rainfall over central and
southeastern Australia resulted in a maintenance or increase of deficiencies in these areas. In particular, serious and
severe deficiencies have expanded over southwestern Victoria and SA. Areas of lowest on record expanded in the
far east of Victoria and adjoining south-eastern NSW between Orbost and Bombala and on the east coast of Tasmania
between Hobart and St. Helens. Significant areas of lowest-on-record rainfall have developed in central Gippsland around
Sale. The record dry start to spring across SA, and the third driest start to spring in Victoria, has contributed to the expansion
of areas of rainfall deficiencies across these states in recent months. The timing of these below average falls has placed severe
stress on farming activities in these regions.
Rainfall deficiencies for the 17-month period from June 2007 to October 2008 persisted over much of
SA, southern NT and also in parts of southern WA, far western parts of both Queensland and NSW, western and central Victoria and northern and
eastern Tasmania. The largest area of lowest on record rainfall for the period is in eastern Tasmania, with some small isolated areas of lowest on
record falls evident elsewhere, especially in SA. The anomalies are all the more remarkable given that they partly coincide with a La Niņa event.
La Niņa events are usually associated with above average rainfall across much of the eastern half of Australia rather than widespread rainfall
deficiencies. The areas of long-term deficiencies generally highlight areas that failed to receive good falls during the 2007/08 La Niņa event,
with large areas of deficiencies through central and southern parts of the country. Although some regions, especially in the northeast, saw
above average rainfall between November 2007 and February 2008, months of below average rainfall before and after this period have
dominated long-term anomalies, especially in southeastern and central parts of Australia.
There were only small changes in the areas of long-term deficiencies in October, with some increase in the area of serious and severe deficiency
over SA and Victoria. The area of lowest on record totals increased in number in SA and expanded in eastern Tasmania.
The deficiencies discussed above have occurred against a backdrop of decade-long rainfall deficits and record
high temperatures that have severely stressed water supplies in the east and southwest of the country.
The combination of record heat and widespread drought during the past five to ten years over large parts
of southern and eastern Australia is without historical precedent and is, at least partly, a result of climate change.
For more information go to a recent
Special Climate
Statement on the long-term drought in southern Australia "Long-term rainfall deficiencies continue in southern Australia while wet conditions dominate the south",
issued 10 October 2008. A dry October over much of southeastern Australia has, in many cases, increased the magnitude of the three and seven year records
at the stations identified in the statement, and more stations have set three-year records, especially in Tasmania.
Rainfall
deficiency maps for standard periods out to three years are
available.
Note: The terms used to describe rainfall in these
Drought Statements have the following meanings -
Serious deficiency
- rainfalls in the lowest 10% of historical totals,
but not in the lowest 5%
Severe deficiency
- rainfalls in the lowest 5% of historical totals
Lowest on record
- lowest since at least 1900 when the data analysed begin
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
For more information regarding this rainfall
deficiencies statement, please contact the following
climate meteorologists in the National Climate Centre:
Lynette Bettio on (03) 9669 4165
Blair Trewin on (03) 9669 4623
David Jones on (03) 9669 4085
External Sites Relating to Drought
The Bureau of Meteorology does not make formal drought declarations
as these are done by either the relevant State Governments or by the
Australian Government. The Australian Government Program is called
Exceptional Circumstances
and it is administered by the Federal Department of Agriculture,
Fisheries and Forestry (DAFF). General information about Australian
Government drought assistance is available at
http://www.daff.gov.au/droughtassist.
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