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 and Bogan Rivers, 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 | 1,329 millimetres (52 in) | 1,081 millimetres (43 in) | 1873 |
| Nyngan | 1,123 millimetres (44 in) | 817 millimetres (32 in) | 1879 |
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 Asian aerosols 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 gases 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.
Read more about this topic: 1950 Australian Rainfall Records
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