WANDA

History

Tropical Cyclone Wanda began as a low pressure area southwest of Willis Island in the Coral Sea on 20 January 1974, forming in the wake of Tropical Cyclone Vera, which had drifted away from the region in the preceding days. The low developed slowly as it tracked east-southeast, moving away from the Queensland coast. On 23 January it turned onto a south-southwest heading and steadily organised, earning the name Wanda on 24 January.

Wanda reached Category 2 strength before crossing the Queensland coast just north of Double Island Point, passing over Fraser Island later on 24 January with a central pressure of about 997 hPa. Once inland the system deteriorated quickly to a tropical low, drifted southwest and dissipated on 25 January.

Although structurally weak, Wanda proved one of the most destructive systems in Queensland's history because of its rainfall and its influence on the monsoon trough, which it drew far to the south. Southern Queensland's catchments were already saturated after an exceptionally wet spring and three weeks of near-continuous rain, and Wanda's moisture pushed the Brisbane, Bremer and Stanley River systems past their limits. Heavy rain began over Brisbane early on 25 January, with 642 mm recorded in a 36-hour period. The Brisbane River burst its banks on 27 January, during the Australia Day weekend, and flood levels peaked at 6.6 m on the Port Office gauge at 2:15 am on 29 January.

Ipswich, Beenleigh and the Gold Coast were also inundated, with the Nerang River flooding cutting the Gold Coast off from Brisbane and around 2,000 people evacuated from riverside and canal homes. Roughly 6,700 to 8,000 homes were flooded and some 13,000 properties affected, with the central business district badly hit. A landslide at Corinda extended 1.6 km into Oxley, forcing evacuations and later demolitions. The partly completed tanker Robert Miller broke its moorings at Kangaroo Point and nearly dammed the river before being secured. Sixteen people died, around 300 were injured, and damage eventually totalled more than A$980 million in 1974 values. The disaster prompted flood mitigation to be built into the design of Wivenhoe Dam.

Sources: Bureau of Meteorology report Wikipedia