Rainfall deficiencies ease in Queensland but persist in other areas
Rainfall for March was very much above average across much of northern and eastern Queensland into southern parts of the Northern Territory, as well as much of Tasmania. A small area centred on the Mid North Coast of New South Wales also saw above average rainfall. Below average rainfall was recorded across much of the rest of southern Australia, with some areas of very much below average, decile 1 (lowest 10%), rainfall.
Compared to the previous Drought Statement, deficiencies have decreased in inland and western Queensland, and slightly decreased on the east coast of New South Wales between the Manning and Illawarra districts.
Much of the rain in Queensland was from a low at the start of the month, or tropical cyclone Nora toward the end of the month. These both brought heavy rainfall and caused flooding, but did help to ease longer-term rainfall deficiencies. The Weekly Rainfall Update provides commentary on the effect of recent rainfall on rainfall deficiencies each week.
Recent rainfall in Queensland has also decreased rainfall deficiencies in western Queensland that were reported in the previous Drought Statement for the 9 months starting in June 2017. Deficiencies for that period now largely resemble those for the 12 months starting in April 2017. There has been some expansion of deficiencies in South Australia due to the dry start to the year across the region, and this will now be monitored closely at shorter timescales as the southern wet season begins.
It has been a very dry start to the year across much of mainland southeastern Australia. The January to March period was the driest first quarter of the year for New South Wales as a whole since 1986. Areas of rainfall deficiency are present at this 3-month period across large areas of northwestern Victoria into southeastern South Australia and some central and western parts of New South Wales, with some areas having less than 25 mm of rainfall over the last three months. Whilst these deficiencies are at a climatologically drier time of the year for this region, the Bureau of Meteorology will monitor the situation closely for any further deficiencies as the southern cropping season begins.
12-month rainfall deficiencies
Above average March rainfall decreased rainfall deficiencies in inland and western Queensland, and slightly decreased rainfall deficiencies on the east coast of New South Wales between the Manning and Illawarra districts.
Serious to severe rainfall deficiencies remain across large areas of western to central and southern Queensland; in an area of eastern New South Wales affecting the Illawarra, Central Tablelands, Sydney, and Hunter regions; and in scattered pockets of northern and western New South Wales. Serious or severe deficiencies are also observed across the Flinders Ranges in South Australia, and a small area in eastern Victoria. Rainfall deficiencies remain generally similar along the west coast of Western Australia, but continue to develop along the coast of the South West Land Division with serious rainfall deficiencies in small scattered areas across the southwest.
Soil moisture in the lower layer (from 10 cm to 100 cm deep) for March increased over much of Queensland and Tasmania, and decreased over inland New South Wales and northwestern Victoria.
Soil moisture was above average across much of Western Australia, excluding western coastal areas, areas of the east and north of the Northern Territory, and much of Queensland, especially in the north.
Lower-layer soil moisture was below average for most of most of New South Wales (especially central and western regions), Victoria (especially in the northwest and most of Gippsland), southeastern South Australia, and western coastal areas of Western Australia.
- March rainfall was below average for large areas of southern mainland Australia
- Rainfall was above average for large parts of Queensland (particularly in the north), and much of Tasmania
- Rainfall deficiencies have decreased across western Queensland at the 12-month timescale, due to above average March rainfall
- Deficiencies persist with little change along the west coast of Western Australia and in eastern New South Wales at the 12-month timescale
- A very dry start to the year across much of mainland southeastern Australia
- Lower-layer soil moisture was below average for March across much of southeastern Australia
Product code: IDCKGD0AR0
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.
For the week to 17 April 2018, rainfall was recorded in the Kimberley and southern coast of Western Australia, in parts of the Top End and interior of the Northern Territory, and in an area to the west of Uluru. Rain also fell along much of the east coast and southern interior of Queensland, eastern and parts of northern New South Wales, most of Victoria, Tasmania, and southern South Australia.
During the first half of the week broad areas of low pressure extending across northern and central Australia generated thunderstorms and showers with moderate falls recorded about the Kimberley, central interior of Western Australia, Cape York Peninsula, Top End, and central parts of the Northern Territory. A moist, onshore flow produced showers along Queensland's central coast.
Early in the week, a cold front and surface trough tracked across southeastern Australia and produced light falls in Tasmania, southwestern Victoria and southeastern South Australia. A surface trough located over southwest Western Australia triggered shower activity with light falls recorded across the State's southern coast.
A low pressure system and upper level trough tracking over Tasmania generated thick middle level cloud and thunderstorms, and produced moderate falls in western Tasmania.
During the middle of the week, a pair of vigorous cold fronts tracked across southeastern Australia, and produced a cloudband with embedded thunderstorms and strong to gale force westerly winds. Moderate falls were recorded in southeastern South Australia, southern and northeastern Victoria, western and northern Tasmania, and elevated parts of the Snowy Mountains in New South Wales. A surface trough extending towards the fronts was located through inland Queensland and New South Wales, and triggered showers and thunderstorms; light to moderate falls were reported in northern and eastern parts of New South Wales; also across the southern and central interior, and east coast of Queensland. The passage of further troughs and cold fronts during the remainder of the week generated continuing moderate falls in western Tasmania, with light falls about southern and northeastern Victoria.
At the end of the week, a surface trough near the north Queensland coast produced showers with moderate to locally heavy falls recorded about the northern Cape York Peninsula and north tropical coast of Queensland.
Rainfall totals in excess of 100 mm were recorded in western Tasmania, and elevated areas of the Victorian Alps. The highest weekly total was 138 mm at Lake Margaret in western Tasmania.
Rainfall totals in excess of 50 mm were recorded at several locations in both the Darwin-Daly District in the Northern Territory and the Kimberley in Western Australia, a pocket of the north tropical Queensland coast, about the Mount Lofty Ranges in South Australia, at locations on the southern coast and in northeastern Victoria, and across the western half of Tasmania.
Rainfall totals between 10 mm to 50 mm were observed in parts of the northern Kimberley, and about the Top End, Gulf Country and central parts of the Northern Territory; along parts of Queensland's east coast and southern interior. Totals between 10 mm and 50 mm were recorded in southeastern Australia covering central southern and southeastern South Australia; southwestern, central and northeastern Victoria; about the ranges in southeastern New South Wales, and across most of Tasmania. Falls exceeded 25 mm in most of southwest Victoria and along the Great Dividing Range, and surrounding heavier falls in western and northern.
Small weekly totals, generally up to 10 mm, were recorded along the southern coast of Western Australia, to the west of Uluru, and across much of eastern New South Wales.
Little or no rainfall was recorded in Western Australia away from the Kimberley, central interior and south coast; most of South Australia except for agricultural regions; northwestern Victoria; most of western New South Wales and some areas along the coast; western and southern Queensland; and the Northern Territory away from the Top End, Gulf Country and central interior.
Impact of recent rainfall on deficits
The Drought Statement, issued on 5 April 2018, discusses rainfall deficits over Australia for the 12-month (April 2017–March 2018) period. Rainfall deficit maps are available for these periods as well as for standard periods.
The maps below show the percentage of mean rainfall that has been received for the rainfall deficit period for the 12-month periods ending 17 April 2018.
Rainfall for the period 1 April to 17 April 2018
Serious to severe deficiencies for the 12-month period affect areas of western, southern inland and central Queensland; an area of eastern New South Wales affecting the Illawarra, Central Tablelands, Sydney and Hunter regions; and in scattered pockets of northern and western New South Wales. Serious to severe deficiencies are present across the Flinders Ranges in South Australia, and a small area of coastal eastern Victoria. Deficiencies also persist along the west coast of Western Australia.
Rainfall in the last week made little difference to deficiencies in affected areas. Affected areas of Queensland and New South Wales have received between 30% to 60% of average rainfall for the period. Affected areas in Western Australia have received less than 40% of average, with some areas receiving less than 20% of average for the period.
Product code: IDCKGRWAR0