1955 Hunter Valley floods

The flood overwhelmed rivers on both sides of the Great Dividing Range, creating an inland sea the size of England and Wales.

Worst hit was the inland city of Maitland, which is sited precariously on low-lying land on the Hunter, and which on this occasion was completely inundated by floodwaters.

Heavy rain owing to the influence of La Niña had been occurring over the catchment of the Hunter River since October 1954[1] when, on 23 February 1955, an extremely intense monsoonal depression developed over southern Queensland and north-east New South Wales and moved southwards.

[1][2] The very strong and extremely moist northeasterly airflow meant that over the basin of the Hunter and parts of the Darling River, rainfall amounts for a 24‑hour period were the highest since instrumental records began around 1885.

In Dubbo, four thousand residents were evacuated as the main street was under more than a metre of turgid, muddy water,[1] and the same thing occurred all along the Macquarie River, and at Gilgandra, a third of the buildings were completely destroyed.