HELEN

History

Severe Tropical Cyclone Helen developed from a monsoon low in the north-western Coral Sea on 28 February 1974. The system organised quickly, and on 1 March it was named Helen by the Bureau of Meteorology's Brisbane Tropical Cyclone Warning Centre while located roughly 150 km east of Cape Melville.

Tracking west-southwestward, Helen made an initial crossing of the eastern coast of Cape York Peninsula and traversed the peninsula overland as a weakened low-pressure system before emerging into the eastern Gulf of Carpentaria. The warm, shallow waters of the Gulf allowed rapid reorganisation, and between 3 and 5 March Helen intensified into a Category 3 severe tropical cyclone as it moved steadily westward, passing north of the Sir Edward Pellew Group and Groote Eylandt. At its peak the central pressure fell to approximately 965 hPa, with maximum sustained winds of about 130–140 km/h and gusts near the core exceeding 180 km/h.

Steering then turned the cyclone west-northwestward, taking it across the eastern Top End coastline near Nhulunbuy and onward toward Darwin. Helen made its second landfall near Darwin on 7 March, bringing damaging winds and torrential rain to the city, before moving inland toward the Victoria River district and weakening into a broad inland rain depression on 8 March.

Darwin and surrounding Top End communities bore the brunt of the impact. Hundreds of houses suffered structural roof damage, trees were brought down extensively, light industrial buildings were destroyed, and power and water supplies were interrupted for several days. The cyclone's long overland passage produced persistent heavy rainfall that caused severe flooding in river systems including the Adelaide, Mary and Daly. The Stuart Highway and regional roads were inundated, isolating Darwin by road for close to a week. One death was attributed directly to floodwaters, with several injuries and damage running into millions of dollars.

Helen's passage proved an important warning for Top End emergency authorities about the vulnerability of Darwin to severe cyclones — a lesson underlined just nine months later when Cyclone Tracy devastated the city on Christmas Eve 1974.

Sources: Bureau of Meteorology report Wikipedia