CYCLONE TRACEY, CHRISTMAS 1974

The year 1974 started with tropical cyclone Wanda bringing torrential rain and flooding to Brisbane. It ended with another major Australian population centre being devastated by a cyclone. If Maitland epitomised flooding in Australia, and Ash Wednesday or Black Friday, bushfires, then Tracy comes most readily to Australian minds when cyclones are mentioned.

By world standards, Tracy was a small but intense tropical cyclone at landfall, the radius of gale force winds being only about 50 km. The central pressure of 950 hPa was close to the average for such systems, but the winds were unusually strong. The anemometer at Darwin Airport recorded a gust of 217 km/h before the instrument was destroyed.

Tracy was first detected as a depression in the Arafura Sea on 20 December 1974. It moved slowly southwest and intensified, passing close to Bathurst Island on the 23rd and 24th. Then it turned sharply east-southeastward, and headed straight at Darwin, striking the city early on Christmas Day. Warnings were issued, but - perhaps because it was Christmas eve, and perhaps because no severe cyclone had affected Darwin in many years - many residents were caught unprepared. But even had there been perfect compliance, the combination of extremely powerful winds, and the loose design of many buildings at that time, was such that wholesale destruction was probably inevitable anyway. Forty-nine people were killed in the city and a further 16 perished at sea. The entire fabric of life in Darwin was catastrophically disrupted, with the majority of buildings being totally destroyed or badly damaged, and very few escaping unscathed. The total damage bill ran into hundreds of millions of dollars.

The devastation inflicted on Darwin by cyclone Tracy in December 1974. (Photo courtesy of the Department of Foreign Affairs and Trade).

As usual in such disasters, many communication links failed, but enough survived to let the world know of the catastrophe, and relief measures were soon under way. An airlift involving both civilian and military aircraft was swiftly organised, while many residents chose to drive out. Within several weeks, three-quarters of Darwin's population had left.

This was not the first time Darwin had been severely damaged by a cyclone: it was badly mauled in both January 1897 and March 1937. But as a result of Tracy, much more attention was given to building codes and other social aspects of disaster planning. Darwin was rebuilt and now thrives as one of our most important gateways to Asia.

The route tropical cyclone Tracy took, arriving in Darwin early on Christmas Day, 1974. Each date indicates the position of 10am local time.