Australia is prone to drought partly because of its geography. Our continent spans the latitudes of the subtropical high pressure belt. This is an area of sinking, dry, stable air and usually clear skies. The far north and south of the country come under the influence of reasonably regular rain-bearing systems for at least part of the year. The east coast is normally well watered by moisture from weather driven by the Tasman and Coral seas. However, over most of the country rainfall is low and erratic. Even in the wetter areas, very dry years can disrupt normal activities and lead to water shortages.
Of all the climate challenges to afflict Australia, drought is one of the most feared, and costly. Major droughts, such as that of 1982–83, and the Millennium drought of 1997–2010 can have a significant impact. Apart from crop failure and stock losses, droughts set the scene for bushfires, dust storms, and land degradation.
The Federation drought was one of Australia’s worst droughts. It began in the mid-1890s with the most extreme conditions in late 1901 and 1902.
The 6 years leading up to Federation, in January 1901, saw intermittent dry spells over most of the country, particularly in 1897 and 1899. Over most of Queensland, dry conditions were virtually unbroken from 1897. Most other parts of the country had reasonable rain in 1900 and early 1901, but by spring 1901 very dry weather had set in across eastern Australia.
By August 1902, heavy sheep and cattle losses were reported from Queensland. Rivers in western Queensland dried up, and the Darling River at Bourke virtually ran dry. Further south, towns near the Murray River such as Mildura, Balranald and Deniliquin—then dependent on the river for transport—suffered badly. The national wheat crop was all but lost, with close to the lowest yields of the century.
The drought began to break in mid-December with heavy general rain in Victoria, and more after Christmas. Rains extended to New South Wales and southern Queensland, while northern Queensland had reasonable falls from December onwards.
The 1914 to 1915 drought, although relatively short, was one of the most memorable, primarily due to the failure of the national wheat crop with the rare occurrence of severe drought conditions occurring simultaneously in southeastern and southwestern Australia.
The first signs of drought became evident in 1913. Rainfall in western Victoria, areas of South Australia and central Tasmania, was well below average in the normally wet April–July period. There were timely rains in early spring but the following year saw a strong El Niño.
The year 1914 started off very hot, and southern Victoria suffered from widespread bushfires in February and March. Good rains fell over most of eastern Australia in March and April. But after that extremely dry conditions set in over the southern half of the country. Except in coastal New South Wales, drought became widespread and severe between July and October. May through October 1914 remains the driest such period on record across large areas of the southern States.
Rivers throughout southeastern Australia fell to extremely low levels. The Murray River at Echuca fell to its lowest level ever recorded to that time, with just 2% of its normal flow by December. Downstream of Swan Hill the Murray was reduced to a series of stagnant pools.
By the end of October, the national wheat crop was a total failure. In southwestern Australia less than half the normal rain fell during the critical May–October period. This led to complete crop failure in some districts, and the lowest Western Australian wheat yield of the century. It is unusual for severe drought to hit the major cropping areas of southwestern and southeastern Australia in the same year.
Spring 1914 was also exceptionally warm in the eastern States. October in Victoria, and November in New South Wales, set records for monthly temperature anomalies for any month. These were not broken until the 21st century. In 1914 New South Wales saw its warmest year of the 20th century. It remains the warmest year on record in a few parts of the Riverina and northern Victoria.
Rain in the eastern States in November and December replenished farm dams and generated some grass growth, but dry weather returned to most areas early in 1915. It was not until autumn 1915 that there were drought-breaking rains. These occurred in South Australia, Tasmania, and most of Victoria in April, and in New South Wales in May. Even then, the May rain was too late for strong pasture growth because of cold weather. The drought lasted until July in southern Queensland, and to the end of the year in northern and central Queensland. Coastal New South Wales, which had been largely unaffected in 1914, had a very dry year in 1915, with many northern coastal areas having their driest year on record.
As in the Federation drought, dry conditions were seen frequently from 1937 to 1945 over eastern Australia. Compared with the Federation and Millennium droughts, the World War II drought had more breaks. However, it also had more periods of intense dryness.
Conditions deteriorated in 1937 over New South Wales, Victoria, much of Queensland and parts of Western Australia. Isolated parts of New South Wales, notably the central west, had record-low rainfall.
Despite 1938 being a La Niña year, conditions worsened substantially. Drought intensified in New South Wales and Victoria. It also spread to eastern South Australia and the grain-growing areas of southwest Australia. In Victoria, an extremely dry six-month spell started in August. Forests became tinder-dry, leading to the disastrous Black Friday bushfires of January 1939.
Relief came with heavy rain in late February 1939 over Victoria, South Australia and New South Wales. Rains were generally good over eastern and central Australia for the remainder of 1939. The 1939 rains were only a brief respite. Dry weather set in again in December, and 1940—a strong El Niño year—was one of the driest years of the century over most of southern Australia. By August 1940, the Nepean Dam in New South Wales was empty; water restrictions were imposed in Brisbane in October. In the west, Perth had its driest year of the 20th century. The drought eased slightly in the southeastern States in November, and more emphatically in January 1941, when heavy rain fell.
The second half of 1941 was again very dry along the eastern seaboard, with water restrictions imposed in Sydney from September. Fortunately, 1942 was a year of good general rain, but this was followed by an even worse 1944. 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 River had stopped flowing along most of its course, and by January, the Hawkesbury was dry at North Richmond. By April 1945, most Victorian water storages were empty. The Murray had stopped flowing at Echuca, and Adelaide faced water shortages. There were water restrictions as far north as Townsville. Dust storms occurred in South Australia, northern Victoria and southern New South Wales on many days in the summer of 1944–45. The drought finally ended in the southern States in winter 1945, enabling a good wheat crop that year. It continued into 1946 in southern Queensland and northern New South Wales (where in some regions, 1946 was the worst year of all). It wasn’t until 1947 that significant general rains ended the long drought.
The decade from 1957 was generally dry, and comparable with the droughts of 1895 to 1903 and 1937 to 1945 in area and severity. Large areas of central Australia, and to a lesser extent, northern Australia, were affected between 1957 and 1964. The odd years in this period tended to be worse, with some relief in the intervening even years. Eastern Australia suffered less, up to 1964, but was greatly affected from 1965 to 1968.
Towards the end of 1964, drought had developed over northwestern New South Wales, and extended to most of the country in 1965. Only Western Australia and the far north were unaffected. The first six months of 1965 were particularly dry over the eastern States, central Australia and South Australia. Canberra received just 26 mm (9% of average rainfall) between January and May. There were rains in South Australia between July and September, but hot, dry conditions returned in October. New South Wales and Queensland received temporary relief in December, before another hot, dry interlude over New South Wales. That ended with good rain in March 1966. The 1964 to 1966 period was especially dry in northern, inland New South Wales.
The trend for even years to be generally wetter continued. There were above-average rains in the second half of 1966 over most of central and eastern Australia, except in the far north and western Tasmania. Record August rains provided timely relief over inland pastoral districts of Queensland. In Tasmania a dry end to 1966 set the scene for disastrous fires early in 1967.
Intense drought returned to southeastern Australia in 1967. The first six months were the driest January–June period in the 20th century over large areas of Victoria, southeastern South Australia, and northern and eastern Tasmania. Unseasonal dust storms affected South Australia in late May, and again in late July. By now, parts of southwestern Victoria were being declared drought areas. In Melbourne and Adelaide, 1967 remains the driest year in more than 160 years of records. In contrast, it was very wet on parts of the east coast, and repeated east coast lows in June caused severe beach erosion along the Gold Coast.
The drought began to break early in 1968. There were heavy rains in early January over northern South Australia, and over the rest of that State, except the southeast, in mid-January. By March, useful rain had fallen in most areas. However, drought lingered in southern and eastern Victoria until significant rainfall in late April and May. Most of Australia had useful rainfall in 1968, except the New South Wales coast from Newcastle southwards. Sydney and Eden registered their lowest annual totals for 80 years. Severe spring bushfires affected the Blue Mountains and other areas around Sydney, before general rain in December finally ended the drought there.
For rainfall deficiencies, of up to one year, and their overall impact, the 1982 to 1983 drought was one of Australia’s most severe in the 20th century.
This drought was associated with a very strong El Niño event. In March 1982, reasonable rains were widespread. However, southern Western Australia, experienced an exceptionally dry autumn. With the coming of winter, intense drought became established in most areas east of a line from Alice Springs to Ceduna, in South Australia. Clear skies and low atmospheric moisture levels were accompanied by frequent severe frosts in June and July. Very dry conditions persisted through spring over eastern Australia, except in coastal areas of northern New South Wales. Extensive areas experienced record or near-record low rainfall from April to December.
The coincidence of drought in Australia and a major El Niño event and the increased global observing capability available due to satellites, led to an increase in research, understanding, and communication around the connection between El Niño (and La Niña) and the Australian climate.
By November, dry soil in northwest Victoria was blown away as dust, and water restrictions were imposed in Melbourne. On 24 November the earliest Total Fire Ban in 40 years was proclaimed in Victoria. The upper Murrumbidgee River became a chain of waterholes. By year's end reservoirs fell to levels not known for many years. The wet season failed in much of the Northern Territory and north Queensland, with record-low summer rainfall in some areas. What little rain there was often fell on bare earth and without follow-up, and was therefore of little use. Only northeastern New South Wales and southeastern Queensland truly escaped the drought, although the agricultural areas of Western Australia were less severely affected than the eastern States.
The lowest point was reached in February 1983, with record-low rainfall in parts of Tasmania, and virtually none in Victoria. Southeast Tasmania experienced bushfires on the 1st and 8th, and dust storms swept Victoria on the 8th. The Ash Wednesday fires devastated Victoria and South Australia on the 16th. In far eastern Victoria, fires burned unchecked for most of the month, which was unusual at the time.
Relief came at last in March. An intense low pressure system developed over northwestern Australia on the 12th. Over the next week it drifted eastward with heavy rain and flooding. It then tracked south over New South Wales and Victoria, reaching Tasmania by the 23rd. Substantial rain fell over almost all the drought area, with many record March totals. Abundant follow-up rains in April and May signified the end of the drought.
Between 1997 and 2009 much of southern Australia experienced a prolonged period of dryness. Conditions were particularly severe in the densely populated southeast and southwest. The Murray–Darling Basin and virtually all the southern cropping zones were severely affected. In contrast, it was a wet period in many parts of northern and outback Australia.
A feature of the drought was a long period without major wet episodes. While 2002 and 2006 were the only years which were severely dry over large areas, there were very few periods of sustained above-average rainfall. This prevented water storages from recovering. Melbourne had 13 consecutive years of below-average rainfall from 1997 to 2009. The early stages of the drought were largely confined to Victoria and Tasmania, but from 2001 onwards it extended to most remaining areas of eastern Australia south of the tropics, as well as to the southwest. All capital cities except Darwin were affected by persistent, or periodic, drought episodes.
The Millennium drought was essentially a cool-season drought in southern mainland Australia. It was coupled with warm-season (November to March) rainfall that was above average in most parts, and unusually high in tropical areas. For Tasmania, the dry conditions were present year-round, but were even stronger during the warm season.
The effects of poor rainfall during the cool season were cumulative. The drought took hold through increasing impacts over a series of years. There was long-term drying of vegetation, landscape and drawdown on water resources. For example, Melbourne water storages dropped from 97.5% in October 1996 to only 33% by June 2010. In 2006, inflows into the Murray system fell to the lowest on record. Only irrigation releases kept the river flowing, unlike in the droughts in the first half of the 20th century.
This was perhaps the first major Australian drought that interacted significantly with the slower influence of climate change. Temperatures were much hotter than previous droughts. For example, 2005, 2006, 2007 and 2009 all saw annual average temperatures in the Murray–Darling Basin higher than anything seen previously. Higher temperatures can increase the intensity of drought conditions though higher evaporation and the impact on the health of animals and vegetation. Temperature extremes peaked during the heatwave and bushfires in early 2009. This culminated in the loss of 374 lives in Victoria and many more over the larger southeast in the heatwave leading up to Black Saturday. There were 173 lives lost in the fires.
Rainfall changes due to climate change may have also affected this drought. Both southwest and southeast Australia have seen substantial drying during April to October in recent decades. This includes the wetter parts of the Murray–Darling Basin stretching into southern Queensland. The trend to drier seasons may have played a role in the Millennium drought by limiting recovery between acute dry years.
About this information: taken from Recent rainfall, drought and southern Australia's long-term rainfall decline.
After a particularly wet winter and spring in 2016 over much of Australia, conditions turned dry in 2017. Rainfall in most of the Murray–Darling Basin was substantially below average in 2017, 2018 and 2019. Though these years saw the most widespread dry conditions, in some parts of the country, such as western Victoria and western Queensland, dry conditions had been observed during 2012–15.
This was a situation with no clear historical precedent. Very dry conditions in the cool season were followed by only a limited recovery in the October–December period in 2017 and 2018. This meant record-low rainfalls over various multi-year periods. The 2019 cool season was comparably dry to those of 2017 and 2018, and saw extreme dry conditions continue to the end of the year.
The three years from January 2017 to December 2019 were the driest on record for any 36-month period starting in January, when averaged over the Murray–Darling Basin and New South Wales. Average rainfall for the Murray–Darling Basin was more than 100 mm lower than the second driest period (January 1965 to December 1967). New South Wales received around 170 mm less rainfall than the next driest period. That was recorded during the Federation drought, the 36 months from January 1900 to December 1902. Other areas affected by longer-term rainfall deficiencies include:
The most extreme rainfall deficiencies over multi-year periods occurred in the northern half of New South Wales. This is the reverse of the situation during the Millennium drought, when the most extreme rainfall deficiencies were in the southern basin with more modest deficits in the north.
Other notable areas with multi-year rainfall deficiencies were Gippsland in eastern Victoria, and eastern Tasmania. In Gippsland, the most extreme deficits focused on a region extending from about Sale to Lakes Entrance. In this area, 2019 was the third successive year of below-average rainfall. While it was not as dry as 2017 and 2018, the continuing below-average rainfall allowed multi-year deficits to accumulate. The east coast of Tasmania also had rainfall that was substantially below average over this period.
A notable feature of the rainfall deficiencies of these three years is that they were especially concentrated in the cooler seasons. Rainfall for April—September was far below average in each of 2017, 2018 and 2019 in most of New South Wales. The situation was the same in Queensland south of the Tropic of Capricorn. All three April−September periods ranked in the 10 driest on record for the Murray–Darling Basin and for New South Wales
One of the strongest positive Indian Ocean Dipoles on record was a substantial contributor to the dry conditions in the second half of 2019. The Southern Annular Mode (SAM) was also in a persistent negative phase for much of the period from September to December (following a marked sudden stratospheric warming over the Antarctic in early spring), resulting in anomalous westerly flow over southern Australia. In spring and early summer, a negative phase of the SAM is typically associated with warm and dry conditions in New South Wales and Queensland.
Across Australia as a whole, spring 2019 saw the highest fire weather danger as measured by the Forest Fire Danger Index (FFDI, a common measure of fire weather conditions), with record high values observed in areas of all States and Territories. The hot conditions further combined with the dry landscape and strong winds to produce dangerous fire weather conditions during December 2019 into early January 2020.
About this information: summarised from Special Climate Statement 70 update-drought conditions in Australia and impact on water resources in the Murray–Darling Basin
Special Climate Statement 72 Dangerous bushfire weather and heat in spring 2019
Special Climate Statement 73 Extreme heat and fire weather in December 2019 and January 2020
Text on 20th-century droughts is adapted from Drought, Dust and Deluge (Bureau of Meteorology, 2004).
Maps of rainfall percentiles were extracted from the AWAP Climate dataset. http://www.bom.gov.au/climate/austmaps/about-rain-maps.shtml