Soil moisture details are reported when there are periods of significant rainfall deficits.
Soil moisture data is from the Bureau's Australian Water Resources Assessment Landscape (AWRA-L) model, developed through the Water Information Research and Development Alliance between the Bureau and CSIRO.
See: Australian Landscape Water Balance.
What is drought?
Drought is a prolonged, abnormally dry period when the amount of available water is insufficient to meet our normal use. Drought is not simply low rainfall; if it was, much of inland Australia would be in almost perpetual drought. Because people use water in so many different ways, there is no universal definition of drought. Meteorologists monitor the extent and severity of drought in terms of rainfall deficiencies. Agriculturalists rate the impact on primary industries, hydrologists compare ground water levels, and sociologists define it by social expectations and perceptions.
It is generally difficult to compare one drought to another, since each drought differs in the seasonality, location, spatial extent and duration of the associated rainfall deficiencies. Additionally, each drought is accompanied by varying temperatures and soil moisture deficits.
Rainfall averages, variability and trends
- Average rainfall: How much rain do you expect?
- Rainfall variability: How consistent is rainfall in your area?
- Rainfall history: Check tables, graphs and data from your local weather station.
- Rainfall trends: Has your rainfall changed?
Lowest on record - lowest since at least 1900 when the data analysed begin.
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.
Above average rainfall for Western Australia eases deficiencies
Rainfall for January was below to very much below average for most of Queensland south of the Cape York Peninsula and across the northeastern third of New South Wales, reaching as far south along the coast as the Illawarra District. Monthly rainfall was also below average for most of Tasmania away from the east, and across southwestern and northwestern Victoria and adjacent areas just across the South Australian border.
Compared to the previous Drought Statement, deficiencies have increased in inland and western Queensland, and on the east coast of New South Wales between the Manning and Illawarra districts.
January rainfall was above average across much of the Cape York Peninsula in Queensland, the northern half and far southwest of the Northern Territory, Western Australia, western to central South Australia, and small parts of the Great Dividing Range in Victoria and southeastern New South Wales.
Rainfall in the Northern Territory and Western Australia was mostly associated with the passage of tropical cyclone Joyce during the first half of the month, and a slow-moving tropical low later in the month. Joyce's remnant low brought heavy rainfall along the west coast leading to daily rainfall records for January at many locations, including around Perth. This rainfall has eased deficiencies across Western Australia at both the 8- and 10-month timescales, although deficiences remain along the northwest coast.
8-month rainfall deficiencies
Above to very much above average January rainfall has alleviated rainfall deficiencies across the Pilbara and northwestern Western Australia.
In eastern Australia, below average rainfall in the last month has increased the size and severity of deficiencies in Queensland and on the east coast of New South Wales. Serious to severe rainfall deficiencies are in place in scattered areas of Queensland between the northwest and the central inland around Longreach and Charleville, and in an area of eastern New South Wales between the Illawarra and the southern end of the Northwest Slopes District, reaching Tamworth in the north and almost to Dubbo in the west.
Deficiencies also persist along the east coast of Tasmania despite a wet December and January. Deficiencies have also emerged in the far northwest of the State. At the shorter 3-month timescale, more widespread deficiencies are evident across western Tasmania.
10-month rainfall deficiencies
Following heavy rainfall associated with the passage of tropical cyclone Joyce, rainfall deficiencies have been alleviated across much of Western Australia, although deficiencies persist along the coast of the Pilbara and Gascoyne between about Karratha and Geraldton.
Meanwhile, below average rainfall for the east during January has exacerbated deficiencies in Queensland and on the east coast of New South Wales. In general, after a very wet start to the northern wet season in October, the remainder of the wet season to date (November 2017 to January 2018) has seen below average rainfall across large parts of Queensland.
With a lessening of deficiencies in the west, and an increase in the east, the monitored period has been changed from that commencing March 2017 to that commencing April 2017. As March 2017 saw very much above average rainfall across eastern Queensland and New South Wales, due in large part to tropical cyclone Debbie, and this very wet month was masking deficiencies in subsequent months in affected parts of New South Wales.
Serious or severe rainfall deficiencies are in place across large areas of western to central inland Queensland and a large area of eastern New South Wales between the Illawarra and the southern end of the Northwest Slopes District, reaching to the area around Tamworth in the north and around Dubbo in the west.
Soil moisture in the lower layer (from 10 cm to 100 cm deep) for January generally increased across the western half of Australia, and decreased across the eastern half, when compared to values for December.
Soil moisture was above average across much of Western Australia, although near average for the southeastern Kimberley and much of the southern Interior and the central third of the south coast. Soil moisture was also above average for parts of the west of the Northern Territory and the west of South Australia.
Lower-layer soil moisture was below average for most of the northern half of New South Wales and the central east, reaching as far south as the Illawarra, across northeastern South Australia, much of the east of the Northern Territory, and most of Queensland, but was near average for coastal southeast Queensland. Soil moisture was also below average for Tasmania, most of the western half of Victoria, and adjacent parts of southeast South Australia.
- January rainfall above to very much above average for the western half of Australia and parts of Far North Queensland
- Rainfall deficiencies have eased across Western Australia, but remain along the coast of the Pilbara and Gascoyne at the 10-month timescale
- Rainfall during January below average for most of Queensland south of the Cape York Peninsula, northeastern New South Wales, western to central Tasmania, and parts of western Victoria
- Rainfall deficiencies have increased in eastern Australia, with large areas of western and central inland Queensland and central eastern New South Wales affected
- Lower-layer soil moisture was below average for January across much of eastern Australia
Product code: IDCKGD0AR0