Number of Drought Years 1900 to 2006 Per 10 year period. Graph 1: Number of Drought years per Decade

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1 Dry Spells and Drought Years in the South Eastern Australian Cropping Regions 1900 to Ian Holton, Holton Weather Forecasting Pty Ltd (Phone: ) 12th October 2006 The current bad drought of 2006, the bad drought of 2002, when combined together with the poor rainfall and hot Spring of 2004, bring many to the question. Is drought becoming more frequent and severe in the South Eastern Australian cropping regions? To answer the first part of the question, as regards frequency of drought, we need to view the 1900 to 2006 period in some detail. Here we are defining a drought in the Southern Australian cropping regions as a Growing Season in which the rainfall was in the vast majority of the cropping regions of South Australia, Victoria and Southern New South Wales were included in the Below Average to Well Below Average Rainfall Decile Categories. Years as such were: 1902, 1911, 1913, 1914, 1919, 1927, 1928, 1929, 1937, 1938, 1940, 1944, 1946, 1957, 1959, 1967, 1972, 1976, 1977, 1982, 1994, 2002, and this current year, Let s look at this drought year sequence on a graph. Number of Drought Years 1900 to 2006 Per 10 year period to to to to to to to to to to to 06 Drought Number Graph 1: Number of Drought years per Decade It becomes quite obvious from the drought graph and drought figures, that if there is any higher drought frequency period in the South Eastern Australian Cropping Regions, it was the 1910 to year period, when the average number of drought years per decade was almost three years in any 10 year The answer to the second part of the question, re severity, is a much harder question to answer. The severity of the drought includes extra factors, such as, how wet or dry was the preceding year? How much stored soil moisture was present at the start of the drought?, how hot were the temperatures for the year?, how windy was the year?, how much evaporation took place for the year?, how advanced were cropping techniques and equipment at the time?, how frosty was the year?, etc. Looking at just rainfall alone, the 1902, 1914, 1940, 1944, 1967, 1982, 2002, and 2006 drought years stand out as, perhaps, the most severe of the drought years. But in reality, bad droughts that have occurred at the end of a sequence of dry (not necessarily drought years) have bitten the hardest into the agricultural community. This type of dry year sequence followed by a major drought occurred in: 1895 to 1901, culminating in the major 1902 drought: 1911 to 1913, culminating in the 1914 major drought: 1924 to 1928, culminating in the 1929 drought: 1937 to 1946, a 10 year dry period with only 2 reasonable years sandwiched in between, & with major droughts in 1940 and 1944: 1965 to 1966 dry period, culminating in the 1967

2 drought: and the current 2002 to 2004 dry period, culminating (we hope & pray!) in the 2006 major drought. Again it can be seen that the most frequent of these dry periods ending in a major drought were in the 1910 to 1949 forty-year So, we can fairly safely say that drought has NOT become more frequent in the South Eastern Australian cropping regions in recent times. We can also say that the worst type of dry/drought scenario, ie dry periods, followed by a major drought has NOT become more frequent in the South Eastern Australian cropping regions in recent times. As to whether this current 2006 drought is the most severe that we have had since In my opinion it is arguably close to being so...but, then I will leave you with some quotations and web references from some earlier drought years that may temper at little my and your opinion on the current 2006 major drought situation: "The year 1902 was one of appalling drought in eastern Australia. Whenever strong winds blew, desiccated soil was whipped into great dust clouds. On the worst day, Wednesday 12 November, northwesterly gales caused exceptional dust storms to sweep across three states. The winds caused considerable damage in their own right...in some towns, "balls of fire" were reported. At Boort in central Victoria they reportedly fell into paddocks and streets, with showers of sparks as they struck the ground. In Chiltern and Deniliquin the balls were blamed for setting fire to buildings..." Short Extract: Courtesy of the Bureau of Meteorology: Other interesting newspaper clippings from the 1902 Drought dust & fireball event :Another example of very high prices resulted from the 1914 drought that affected most Australian States. This severe drought led to virtually no wheat being available for export from Australia in The low production and low stocks, yet increased demand from Australia and overseas, caused wheat prices to increase sharply. Price Risk Management for Australian Broad acre Farmers: some observations Agribusiness Review - Vol Paper 2 ISSN Camels crossing the Murray River, Mildura 1914 Drought Photo: The World War II droughts By April 1944, northern Victoria was carting water, and failure of the winter-spring rains led to failure of the wheat crop. As the drought extended into 1945, large rivers virtually dried up. By December 1944 the Hunter had ceased to flow along most of its course; by January the Hawkesbury was dry at North Richmond. By April 1945, most Victorian water storages were empty, the Murray had ceased to flow at Echuca, and Adelaide faced water shortages. As far north as Townsville were water restrictions. Dust storms raged in South Australia, northern Victoria and southern NSW on many days in the summer of The drought finally ended in the southern States in winter 1945, ensuring a good wheat crop, but continued into 1946 in southern Queensland and northern NSW (in some parts, 1946 was the worst year of the lot!). It wasn't until 1947 that significant general rains effectively ended the long drought. Courtesy Bureau of Meteorology: Full Text can be viewed at In the severe drought of , restrictions were introduced relating to the use of fixed sprinklers and hoses, as well as washing cars and filling swimming pools and fountains. People used buckets to water their gardens, but even this practice was later restricted A dry history: Melbourne Water

3 Photo: A dust-storm rolls across Mildura, Victoria, at the height of the severe drought in south-eastern Australia. Photo courtesy of the Foto-fella Don Turvey and The Mildura and District Historical Society Inc. Author s Note: Historic Growing Season Laminated Rainfall Posters from 1900 to 1999 inclusive, which clearly show all the past drought years, can be obtained from Holton Weather Pty Ltd. Details can be found at Click on the Products Cloud Symbol. A dry decade across the Agricultural areas of South Australia: October 1996 September 2006 Adapted by South Australian Climate Services Centre Bureau of Meteorology Ten-Year Rainfall Deficits October 1996 to September 2006 has been a notably dry decade for the agricultural region of South Australia, along with other parts of southern and eastern Australia. In contrast, much of central and tropical Australia has seen above average accumulated rainfall for the same Figure 1 shows a large area through the South East of South Australia and into Victoria recording its lowest 10-year accumulated rainfall on record (since 1900), while rainfall totals over parts of Eyre Peninsula for the same period have been in the lowest 10% of records. The most extreme low rainfall anomalies Australia-wide over the period occurred in an area around Melbourne, where falls during the last 10 years have widely been about 20% below the long-term average, and 10% below those of any other 10-year period in recorded history. A characteristic feature of the driest areas during this decade is not that there has been a run of exceptionally dry years but rather that there has been a lack of any sustained wet periods. Only two years have recorded significant rainfall deficits: 2002 when very much below average annual totals (ie in the lowest 10% of records) were experienced over most of South Australia and 1997 when parts of the South East recorded very much below average yearly totals. Widespread above average annual falls were limited to year 2000, with some isolated pockets receiving above average rainfall in one other year during the Above average falls are those in the top 30% of records (but not in the top 10%). October 1996 is taken as the starting point for this statement, as September 1996 was the last in a sequence of months with above-average rainfall in the driest hit areas in South Australia and Victoria. An extended dry period such as this has the potential to impact on long term water storage and ground water recharge. Compounding these recent rainfall deficits, the accumulated rainfall totals for the decade preceding were just average. See Figure 2. This earlier period included 1992, one of our wettest years, and 1994 one of our driest in the agricultural region. The dry conditions have continued in 2006, with below average rainfall for the January-September period over most of South Australia and very much below average totals in the Southeast (Fig 3). Winter falls were in the lowest 10% over most of the agricultural region (Fig 4) and very low rainfalls in September and October-to-date have extended the dry conditions.

4 Temperatures since 1996 In addition to being very dry, the last 10 years have been a very warm Average daytime maximum temperatures over the period have been particularly high, and have been the highest on record over all of eastern South Australia (Figure 3). In most of the region maximum temperatures have been 0.5 to 1.0 C above the average, with a few locations exceeding 1.0 C. The situation has been more patchy for overnight minimum temperatures. While some areas have had their warmest 10-year average overnight minimum temperatures, locations in the South East have been below average. Further Information: The following climate meteorologists in the National Climate Centre Dr David Jones ( ), Dr Blair Trewin ( ) or Beth Curran/ Bruce Brooks at the Climate Services Centre SA (ph ) can be contacted about this statement. Maps of recent rainfall and temperature and seasonal outlook information are available from the Bureau s website at Table 1 Record Mean annual rainfalls for October to following September for stations having 90 years of record. Station number Station name Mean annual rainfall, (mm) Long-term mean annual rainfall (mm) Second lowest 10 year mean annual rainfall (mm) and Third lowest 10 year mean annual rainfall (mm) and Fourth lowest 10 year mean annual rainfall (mm) and South Australia Darke Peak* ( ) 346 ( ) 346 ( ) Wirrabara Forest ( ) ) 592 ( ) Crystal Brook ( ) 352 ( ) 353 ( ) Hahndorf ( ) 768 ( ) 777 ( ) Keith ( ) 426 ( ) 428 ( ) Tintinara* ( ) 425 ( ) 429 ( ) Lucindale ( ) 523 ( ) 525 ( ) Nhill ( ) 366 ( ) 368 ( ) Horsham ( ) 403 ( ) 404 ( ) Melbourne ( ) 574 ( ) 590 ( ) * for stations with only 80 years of record. Figures

5 Figure 1. Australian rainfall deciles for the 10 year period October 1996 to September Figure 2. The preceding 10-year (October September 1996) accumulated rainfall, showing average rainfall accumulations over most of the Southeast and Eyre Peninsula. Figure Rainfall anomalies for the 9 month period to 30 September. Figure 4. Rainfall anomalies for Winter 2006 showing lowest on record in the South East. Figure 5(a). Maximum temperature deciles for the decade 1996 to Figure 5(b). Minimum temperature deciles for the decade 1996 to 2006.