NANCY

History

Tropical Cyclone Nancy began as a cluster of monsoonal cloud over the central Coral Sea, first identified as a tropical low on 26 January 1990. The disturbance initially tracked in a parabolic arc towards the equator, gradually becoming better organised as an amplifying upper-level trough opened strong outflow channels above it. By 31 January the low had acquired sufficient structure to be classified as a Category 1 tropical cyclone and was named Nancy by the Brisbane Tropical Cyclone Warning Centre, at a position northeast of New Caledonia.

Steered by complex upper-level troughing, Nancy turned first southward and then southwestward, heading directly towards the South East Queensland coast. It reached its peak intensity early on 1 February as a Category 2 system, with a minimum central pressure near 975 hPa and maximum ten-minute sustained winds of roughly 100 km/h; gusts in excess of 130 km/h were recorded. Through 1 and 2 February the cyclone moved slowly and erratically just offshore, passing within about 180 km of the Sunshine Coast and Gold Coast without the centre crossing the coast. Encountering cooler water and increasing vertical shear, Nancy weakened and completed extratropical transition on 4 February off northern New South Wales. The remnant low retained a deep surface centre as it traversed the southern Tasman Sea, finally dissipating west of New Zealand on 8 February.

Despite remaining offshore, Nancy's outer rainbands delivered torrential rainfall to the coastal ranges south of Brisbane, with some stations recording up to 530 mm in 24 hours, including 132 mm in a three-hour period. The resulting flash flooding was severe across the Gold Coast hinterland, the Nerang River catchment and northern New South Wales. Four people drowned in floodwaters — among them a canoeist swept away in a swollen creek near Canungra — although some accounts place the toll at five. The system's slow offshore movement also produced damaging seas, storm surge and extensive beach erosion from the Sunshine Coast to Tweed Heads, along with road closures and power failures around Brisbane and Moreton Bay.

Sources: Bureau of Meteorology report Wikipedia