1950 Australian rainfall records
Encyclopedia
The 1950 rainfall records for the Australia
n states of New South Wales
and Queensland
reported probably the most remarkable record high rainfall totals ever recorded anywhere in the continent. Averaged over both of these states, 1950 is clearly the wettest year since adequate records became available circa 1885. Queensland recorded a statewide average rainfall of around 1125 millimetres (44.3 in) as against a mean since 1885 of around 640 millimetres (25.2 in), whilst New South Wales recorded around 930 millimetres (36.6 in) as against an instrumental mean around 520 millimetres (20.5 in). Australia's wettest town, Tully
also recorded its highest annual rainfall total in 1950 with a phenomenal 7898 millimetres (310.9 in)
and generally very cool conditions further south. A major cyclone in the third week of January gave substantial rain to most of New South Wales and caused high winds that killed seven people, but it was not until February that the pattern of abnormal rainfall over NSW and Queensland became firmly established.
Especially heavy rainfall occurred over the southwest of New South Wales (extending into most of Victoria
) during February, but it was in March, normally at the end of the wet season, that the heaviest rainfall occurred. The monsoon trough, which is normally situated around Cape York Peninsula, moved to a latitude near Boulia
. At the beginning of that month some of the worst flooding on record occurred over the Barron
and Herbert River
s, and with a major tropical cyclone
following the contour of the Queensland coast for over a week from 4 to 11 March and then moving inland, the heavy rain extended deep into the interior of Queensland and even to that part of South Australia
northeast of the Flinders Ranges
. The flood on the Diamantina River
was measured as the highest ever recorded, and Windorah on the lower Cooper
recorded for the entire month 442 millimetres (17.4 in), which is about 145 percent of its mean annual rainfall. Most pastoral areas were described as having a "superabundance of feed" and losses of sheep in the Lake Eyre Basin
due to blowfly strike were as serious as experienced in the frequent droughts characteristic of the basin's extraordinarily variable climate.
With the interaction with a cold front mid-month, the heavy rainfall shifted southward to the Murrumbidgee River
basin. In three days, Canberra
received 150 millimetres (6 in) and the heavy rain continued over southeastern New South Wales and adjacent Victoria until the end of the month. Major flooding – unusual for this time of year – occurred on all rivers draining from the Australian Alps
and over the South Coast
. By the time the rain eased after further heavy falls early in April, Canberra had had its second wettest month on record. Over the North Coast up to Brisbane
and inland to the Darling Downs, however, March rainfall had been below normal.
In these regions, however, the moist easterly flow of March continued to bring heavy rainfall later in April; however, in much of western and far southern New South Wales April was very dry. The continuing rain, aided by falls near Lake Eyre that prevented the rivers drying up, allowed the lake to begin filling during that month to the astonishment of many people who had seen the lake during the dry era from 1922 to 1938
and concluded that the lake could never fill with water.
From the second week of June to the end of winter, the weather patterns became quite unusual. Strong high-pressure systems over Tasmania
and Victoria were virtually constant and allowed moist easterly air to flow consistently over New South Wales and Queensland. Combined with a series of upper-level lows lifting the moisture, this caused remarkably heavy rain except over the extreme south of New South Wales, where it was dry and the ski season
extremely poor. June 1950 was Sydney
's wettest month on record with 643 millimetres (25.3 in), whilst at Dorrigo on the edge of the coastal escarpment, over 1400 millimetres (55.1 in) fell in the last three weeks of the month and 624 millimetres (24.6 in) on the 24th alone. Even at normally dry Longreach, 160 millimetres (6.3 in) fell for June and 140 millimetres (5.5 in) for July. Most extraordinary, however, was on the Central Coast of Queensland, where Bowen received over 400 millimetres (15.7 in), or twenty times its normal July rainfall.
Owing to the moist easterly flow, temperatures for the winter were remarkably mild. At Inverell
, the mean minimum for July was 6 °C (43 °F), which is as much as 6°C above normal and an incredible 10°C (18°F) higher than had been recorded just four years previously.
The consequences of this heavy rain falling on saturated catchments with absolutely no drying westerly winds was disastrous. Most rivers on the coast of New South Wales, and many further inland, reached record levels. Food shortages were particularly prevalent in Sydney and surrounding cities, and railways and roads were repeatedly cut as each successive storm flooded all major rivers. Vegetable
crops on the Hawkesbury River were hardest hit, with most being completely destroyed and prices skyrocketing.
Except for a central portion of New South Wales, August was fairly dry. However, the continued absence of frost
or westerly winds meant that at the end of winter catchments were still extremely wet. With the Southern Oscillation Index firmly established as strongly positive after a couple of years near zero, it was clear that further heavy rain was always imminent.
Wheat crops in all of Queensland and all but the Riverina
in NSW, which had needed some fine weather to finish, were almost completely destroyed by the excessive rainfall. Many farmers had no crop at all because of rust
and many other crops were fed to cattle
as their quality as grain was extremely poor.
The continued rain and mild conditions (warm in the south, cool in the tropics) led to an outbreak of Murray Valley encephalitis which killed 19 people during the subsequent summer. It had the remarkable positive, however, of allowing the first curbs to the rabbit
plague in Australia via myxomatosis
, which had not spread in the dry era since 1922 because of the absence of standing water for mosquito
es to breed.
December was very wet in the north, with many rainfall records in the Georgina River
basin, but was hot and dry in New South Wales except around Tibooburra in the far northwest. Between Sydney and Dubbo it was the first drier-than-normal month since 1949.
Although record rainfall occurred over about two-thirds of New South Wales and half of Queensland, the most remarkable rainfalls occurred over the central inland of New South Wales. At many stations in the basins of the Macquarie
and Bogan River
s, the 1950 annual rainfall are as much as 250 millimetres (10 in) higher than that of the second-wettest year in a record of around 130 years:
Some stations show similar differences in 1974 (central Australia) and 2000 (Northern Territory
, Kimberley and Pilbara). However, it is probable that by then global warming
and possibly Asia
n aerosol
s were influencing Australia's climate and thus these are not natural variability, which the record 1950 rainfalls above undoubtedly are.
Using a normal distribution one can estimate the return period
of 1950-level annual rainfall for the Dubbo region as around 375 years, or about three times the length of instrumental rainfall data. For areas even a little further west, however, the skewness
is too high to use this method, but there can be little doubt that the return periods are similar. Excluding records post-1968, when enhanced greenhouse gas
es has undoubtedly impacted Australian rainfall beyond (admittedly generally high) natural variability, there are no other totals over a substantial area that compare for improbability of being repeated.
The extreme absence of westerly winds meant that unlike 1956, 1973 and 1974, the year 1950 was not uniformly wet over Australia: indeed, in much of Tasmania and Western Australia the anticyclonic control associated with the moist airflow over New South Wales and Queensland produced unusually dry conditions. (A remarkable statistic associated with this is that, although the fourth wettest year averaged over Australia, 1950 had a higher proportion of Australia in the lowest 10 percent than 68 out of 106 other years since 1900.
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n states of New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
and Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
reported probably the most remarkable record high rainfall totals ever recorded anywhere in the continent. Averaged over both of these states, 1950 is clearly the wettest year since adequate records became available circa 1885. Queensland recorded a statewide average rainfall of around 1125 millimetres (44.3 in) as against a mean since 1885 of around 640 millimetres (25.2 in), whilst New South Wales recorded around 930 millimetres (36.6 in) as against an instrumental mean around 520 millimetres (20.5 in). Australia's wettest town, Tully
Tully, Queensland
Tully is a small town in Queensland, Australia, adjacent to the Bruce Highway approximately south of Cairns by road and north of Townsville. At the 2006 census, Tully had a population of 2,457....
also recorded its highest annual rainfall total in 1950 with a phenomenal 7898 millimetres (310.9 in)
First four months
The year 1950 opened quite quietly over Australia, with a relatively inactive monsoonMonsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
and generally very cool conditions further south. A major cyclone in the third week of January gave substantial rain to most of New South Wales and caused high winds that killed seven people, but it was not until February that the pattern of abnormal rainfall over NSW and Queensland became firmly established.
Especially heavy rainfall occurred over the southwest of New South Wales (extending into most of Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
) during February, but it was in March, normally at the end of the wet season, that the heaviest rainfall occurred. The monsoon trough, which is normally situated around Cape York Peninsula, moved to a latitude near Boulia
Boulia, Queensland
Boulia is a town in Central West Queensland, Australia. It is located approximately by road south of Mount Isa, and lies on the Burke River, which was named after the explorer Robert O'Hara Burke who passed through the area with the Burke and Wills expedition in 1860. The township was gazetted in...
. At the beginning of that month some of the worst flooding on record occurred over the Barron
Barron River (Queensland)
The Barron River is located on the Atherton Tableland inland from Cairns in Northern Queensland, Australia. With its headwater at Lake Tinaroo, it is more than 165 km long and has a catchment area of approximately 2138 km².-History:...
and Herbert River
Herbert River
The Herbert River is a river located in Far North Queensland, Australia. The southernmost of Queensland's wet tropics river systems, it is named after Robert George Wyndham Herbert , the first Premier of Queensland...
s, and with a major tropical cyclone
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
following the contour of the Queensland coast for over a week from 4 to 11 March and then moving inland, the heavy rain extended deep into the interior of Queensland and even to that part of South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
northeast of the Flinders Ranges
Flinders Ranges
Flinders Ranges is the largest mountain range in South Australia, which starts approximately north west of Adelaide. The discontinuous ranges stretch for over from Port Pirie to Lake Callabonna...
. The flood on the Diamantina River
Diamantina River
The Diamantina River is a river in south west Queensland and the far north of South Australia. Rising north-west of Longreach in the Swords Range, it flows in a south-westerly direction through central Queensland and the Channel Country to form the Warburton River at its confluence with the...
was measured as the highest ever recorded, and Windorah on the lower Cooper
Cooper Creek
Cooper Creek is one of the most famous and yet least visited rivers in Australia. It is sometimes known as the Barcoo River from one of its tributaries and is one of three major Queensland river systems that flow into the Lake Eyre Basin...
recorded for the entire month 442 millimetres (17.4 in), which is about 145 percent of its mean annual rainfall. Most pastoral areas were described as having a "superabundance of feed" and losses of sheep in the Lake Eyre Basin
Lake Eyre Basin
The Lake Eyre basin is a drainage basin that covers just under one-sixth of all Australia. The Lake Eyre Basin is the largest endorheic basin in Australia and amongst the largest in the world, covering about 1,200,000 square kilometres, including much of inland Queensland, large portions of South...
due to blowfly strike were as serious as experienced in the frequent droughts characteristic of the basin's extraordinarily variable climate.
With the interaction with a cold front mid-month, the heavy rainfall shifted southward to the Murrumbidgee River
Murrumbidgee River
The Murrumbidgee River is a major river in the state of New South Wales, Australia, and the Australian Capital Territory . A major tributary of the Murray River, the Murrumbidgee flows in a west-northwesterly direction from the foot of Peppercorn Hill in the Fiery Range of the Snowy Mountains,...
basin. In three days, Canberra
Canberra
Canberra is the capital city of Australia. With a population of over 345,000, it is Australia's largest inland city and the eighth-largest city overall. The city is located at the northern end of the Australian Capital Territory , south-west of Sydney, and north-east of Melbourne...
received 150 millimetres (6 in) and the heavy rain continued over southeastern New South Wales and adjacent Victoria until the end of the month. Major flooding – unusual for this time of year – occurred on all rivers draining from the Australian Alps
Australian Alps
The Australian Alps are the highest mountain ranges of mainland Australia. They are located in southeastern Australia and straddle the Australian Capital Territory, south-eastern New South Wales and eastern Victoria...
and over the South Coast
South Coast, New South Wales
The South Coast refers to the narrow coastal belt from Sydney in the north to the border with Victoria in the south in the south-eastern part of the State of New South Wales, Australia. It is bordered to the west by the coastal escarpment of the Southern Tablelands, which is largely covered by a...
. By the time the rain eased after further heavy falls early in April, Canberra had had its second wettest month on record. Over the North Coast up to Brisbane
Brisbane
Brisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...
and inland to the Darling Downs, however, March rainfall had been below normal.
In these regions, however, the moist easterly flow of March continued to bring heavy rainfall later in April; however, in much of western and far southern New South Wales April was very dry. The continuing rain, aided by falls near Lake Eyre that prevented the rivers drying up, allowed the lake to begin filling during that month to the astonishment of many people who had seen the lake during the dry era from 1922 to 1938
Climate change in Australia
Climate change has become a major issue in Australia due to drastic climate events since the turn of the 21st century that have focused government and public attention. Rainfall in Australia has increased slightly over the past century, although there is little or no trend in rainfall in northeast...
and concluded that the lake could never fill with water.
Second four months
May and the first week of June saw a relatively typical winter circulation over most parts of Australia. However, the tendency of strong frontal depressions to move inland combined with generally weak anticyclones meant that temperatures were generally mild, whilst a major low pressure system off the south coast gave that region further flooding rains.From the second week of June to the end of winter, the weather patterns became quite unusual. Strong high-pressure systems over Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
and Victoria were virtually constant and allowed moist easterly air to flow consistently over New South Wales and Queensland. Combined with a series of upper-level lows lifting the moisture, this caused remarkably heavy rain except over the extreme south of New South Wales, where it was dry and the ski season
Skiing
Skiing is a recreational activity using skis as equipment for traveling over snow. Skis are used in conjunction with boots that connect to the ski with use of a binding....
extremely poor. June 1950 was Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
's wettest month on record with 643 millimetres (25.3 in), whilst at Dorrigo on the edge of the coastal escarpment, over 1400 millimetres (55.1 in) fell in the last three weeks of the month and 624 millimetres (24.6 in) on the 24th alone. Even at normally dry Longreach, 160 millimetres (6.3 in) fell for June and 140 millimetres (5.5 in) for July. Most extraordinary, however, was on the Central Coast of Queensland, where Bowen received over 400 millimetres (15.7 in), or twenty times its normal July rainfall.
Owing to the moist easterly flow, temperatures for the winter were remarkably mild. At Inverell
Inverell, New South Wales
Inverell is a town in northern New South Wales, Australia, situated on the Macintyre River. It is also the centre of Inverell Shire. Inverell is located on the Gwydir Highway on the western slopes of the Northern Tablelands. It has a temperate climate...
, the mean minimum for July was 6 °C (43 °F), which is as much as 6°C above normal and an incredible 10°C (18°F) higher than had been recorded just four years previously.
The consequences of this heavy rain falling on saturated catchments with absolutely no drying westerly winds was disastrous. Most rivers on the coast of New South Wales, and many further inland, reached record levels. Food shortages were particularly prevalent in Sydney and surrounding cities, and railways and roads were repeatedly cut as each successive storm flooded all major rivers. Vegetable
Vegetable
The noun vegetable usually means an edible plant or part of a plant other than a sweet fruit or seed. This typically means the leaf, stem, or root of a plant....
crops on the Hawkesbury River were hardest hit, with most being completely destroyed and prices skyrocketing.
Except for a central portion of New South Wales, August was fairly dry. However, the continued absence of frost
Frost
Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...
or westerly winds meant that at the end of winter catchments were still extremely wet. With the Southern Oscillation Index firmly established as strongly positive after a couple of years near zero, it was clear that further heavy rain was always imminent.
Last four months
September continued mild with rainfall ranging from nil in western NSW to again very heavy around Dubbo and Nyngan, but October and November, with cold air continually interacting with moist easterly winds, saw a return to the extreme wet conditions of June and July. In these two months Dubbo received a total of 420 millimetres (16.5 in) of rain and the flooding of March returned to the reprieved southeastern areas of New South Wales. By the end of October a large number of stations had already exceeded annual records set in the 1890s.Wheat crops in all of Queensland and all but the Riverina
Riverina
The Riverina is an agricultural region of south-western New South Wales , Australia. The Riverina is distinguished from other Australian regions by the combination of flat plains, warm to hot climate and an ample supply of water for irrigation. This combination has allowed the Riverina to develop...
in NSW, which had needed some fine weather to finish, were almost completely destroyed by the excessive rainfall. Many farmers had no crop at all because of rust
Rust
Rust is a general term for a series of iron oxides. In colloquial usage, the term is applied to red oxides, formed by the reaction of iron and oxygen in the presence of water or air moisture...
and many other crops were fed to cattle
Beef cattle
Beef cattle are cattle raised for meat production . The meat of cattle is known as beef. When raised in a feedlot cattle are known as feeder cattle. Many such feeder cattle are born in cow-calf operations specifically designed to produce beef calves...
as their quality as grain was extremely poor.
The continued rain and mild conditions (warm in the south, cool in the tropics) led to an outbreak of Murray Valley encephalitis which killed 19 people during the subsequent summer. It had the remarkable positive, however, of allowing the first curbs to the rabbit
Rabbit
Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world...
plague in Australia via myxomatosis
Myxomatosis
Myxomatosis is a disease that affects rabbits and is caused by the Myxoma virus. It was first observed in Uruguay in laboratory rabbits in the late 19th century. It was introduced into Australia in 1950 in an attempt to control the rabbit population...
, which had not spread in the dry era since 1922 because of the absence of standing water for mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
es to breed.
December was very wet in the north, with many rainfall records in the Georgina River
Georgina River
The Georgina River is the north-westernmost of the three major rivers of the Channel Country in western Queensland that flow in extremely wet years into Lake Eyre.-Geography:...
basin, but was hot and dry in New South Wales except around Tibooburra in the far northwest. Between Sydney and Dubbo it was the first drier-than-normal month since 1949.
Evaluation
The extremely widespread flooding that resulted from record rains and unusually low evaporation caused at least 26 deaths on the North Coast during the winter.Although record rainfall occurred over about two-thirds of New South Wales and half of Queensland, the most remarkable rainfalls occurred over the central inland of New South Wales. At many stations in the basins of the Macquarie
Macquarie River
The Macquarie River is one of the main inland rivers in New South Wales. Its headwaters rise in the central highlands of New South Wales near the town of Oberon. The river travels generally northwest past the towns of Bathurst, Wellington, Dubbo, Narromine, and Warren to the Macquarie Marshes...
and Bogan River
Bogan River
The Bogan River is an inland river in the central west of New South Wales, Australia.This river rises at Goonumbla, 19 kilometres north-west of Parkes and flows in a generally north-north-westerly direction past Tottenham, Peak Hill and through Nyngan. The Bogan River is about 590 km in length...
s, the 1950 annual rainfall are as much as 250 millimetres (10 in) higher than that of the second-wettest year in a record of around 130 years:
| Station | 1950 rainfall | Rainfall of second-wettest year |
Records begin in |
|---|---|---|---|
| Dubbo | 1329 millimetres (52 in) | 1081 millimetres (43 in) | 1873 |
| Nyngan | 1123 millimetres (44 in) | 817 millimetres (32 in) | 1879 |
Some stations show similar differences in 1974 (central Australia) and 2000 (Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
, Kimberley and Pilbara). However, it is probable that by then global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
and possibly Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n aerosol
Aerosol
Technically, an aerosol is a suspension of fine solid particles or liquid droplets in a gas. Examples are clouds, and air pollution such as smog and smoke. In general conversation, aerosol usually refers to an aerosol spray can or the output of such a can...
s were influencing Australia's climate and thus these are not natural variability, which the record 1950 rainfalls above undoubtedly are.
Using a normal distribution one can estimate the return period
Return period
A return period also known as a recurrence interval is an estimate of the interval of time between events like an earthquake, flood or river discharge flow of a certain intensity or size. It is a statistical measurement denoting the average recurrence interval over an extended period of time, and...
of 1950-level annual rainfall for the Dubbo region as around 375 years, or about three times the length of instrumental rainfall data. For areas even a little further west, however, the skewness
Skewness
In probability theory and statistics, skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable. The skewness value can be positive or negative, or even undefined...
is too high to use this method, but there can be little doubt that the return periods are similar. Excluding records post-1968, when enhanced greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...
es has undoubtedly impacted Australian rainfall beyond (admittedly generally high) natural variability, there are no other totals over a substantial area that compare for improbability of being repeated.
The extreme absence of westerly winds meant that unlike 1956, 1973 and 1974, the year 1950 was not uniformly wet over Australia: indeed, in much of Tasmania and Western Australia the anticyclonic control associated with the moist airflow over New South Wales and Queensland produced unusually dry conditions. (A remarkable statistic associated with this is that, although the fourth wettest year averaged over Australia, 1950 had a higher proportion of Australia in the lowest 10 percent than 68 out of 106 other years since 1900.