The Hunter Valley is one of the prominent geographical features of Eastern New South Wales, standing out as a tongue of lowland penetrating deeply from the coast into the highlands of the Great Dividing Range for a distance of about 125 miles.

The mean rainfall over the Hunter Catchment during the four months preceding the flood of February 1955, was approximately 150 per cent. of normal. This wet season was followed by rains of substantial proportion during the period 14th to 17th February 1955, when the mean rainfall for the Valley was 4.7 inches, with falls up to 11 inches in the upper reaches of the catchment. This rain was sufficient to cause a minor flood in the Hunter River at Maitland, where the river reached a height of 26 feet 3 inches at the Belmore Bridge gauge, and a major flood in the Williams River. Conditions at the time were warm and humid with scattered rains, evaporation was below normal, and, as a consequence, the soil throughout the catchment remained wet. The catchment was therefore well saturated, and, in the event of further heavy rains, the stage was set for major flood.