Gough Whitlam flew into Darwin a few days after killer cyclone Tracy exploded across the city in the early hours of Christmas Eve 1974.
The PM wore two grim expressions—one as the extent of the damage and lives lost unfolded and the other, perhaps, from the realisation that this federal government city was dreadfully unprepared, built entirely without proper structural building codes.
The city’s entire infrastructure was the commonwealth’s responsibility, with a large proportion of its houses built and owned by the federal government and occupied mostly by government employees.
The associated construction and maintenance activities were the responsibility of the Department of Housing and Construction.
Commemorations continue this month, 50 years after an event that killed 66 people and caused $837 million in damage, about $7.69 billion in 2025 terms. It destroyed more than 70% of Darwin’s buildings, including 80% of houses, and left more than 25,000 out of the 47,000 inhabitants of the city homeless before landfall and required the evacuation of over 30,000 people, of whom many never returned.
A small, developing, easterly storm that would become cyclone Tracy, was originally expected to pass clear of the city, but it turned towards it early on December 24.
After 10 pm, the damage became severe, with wind gusts reaching 217 kph before the instruments failed. The anemometer at the Darwin Airport control tower had its needle bent in half by the strength of the gusts.
Darwin residents were celebrating Christmas, and they didn’t immediately acknowledge the emergency, partly because they had been alerted to the earlier cyclone Selma, which passed west of the city but did not affect it in any way.
Two months after the disaster, Whitlam announced the creation of the Darwin Reconstruction Commission. It took 3.5 years to rebuild the city. More than 2500 homes were built or repaired by the time it officially ended in mid-1978.
The resulting evacuation of most of the population was the largest ever conducted in Australia. It had long- lasting social effects on many of those who experienced it, but although still the subject of controversy, it is difficult to see how they could have been looked after if they had stayed in Darwin.
This was Tracy’s real tragedy, and the government resolved that it would never happen again. Without this resolve, it is questionable whether the impact on building design and construction would have been as great as it was. It also had a major impact on the insurance industry, although not nearly as great as it could have been.
Darwin was rebuilt using more stringent standards and ‘cyclone codes’ that met all regulations for bracing.
This, and similar instances of extreme wind and storm conditions, hammer home the importance of being prepared for the worst with proper construction design.
The regular appearance of tropical cyclones in Australia’s northern regions and the occurrence of many ‘freak’ storms underlines the need to place more emphasis on structural wood fasteners in the building and repair of structures in disaster-prone areas.
A well-built conventional timber frame structure tied together with engineered structural wood fasteners and anchored to an adequate foundation will withstand the major effects of cyclones. This type of construction demonstrates remarkable resistance to high winds when each component is proper fastened to the other.
We are familiar with the saying that a chain is only as strong as its weakest link, and the weakest link in construction is the inadequate fastening of structural components.
Even where building codes are faithfully followed there have been instances where some parts of the building have been securely connected, but for a variety of reasons, other parts have been neglected.
The essential basis for a storm-resistant construction is that everything must be anchored down from the foundation to the roof. Building codes have been developed and adopted throughout Australia to provide minimum standards in design, construction and use of material in building.
Most storm damage to structures is caused initially by the failure of joint fastenings—not structural or finish materials. A roof may not be anchored sufficiently, a wall may come loose at the floor, and extreme winds may move houses off their foundations or overturn them.
In almost every case, the outstanding factor causing major damage or complete destruction is the lack of suitable anchorage of the whole structure to the ground.
The havoc often resulting from forces release by cyclones can be minimised by well-known and generally proven construction practices which are applicable to all types of construction.
Such storm-resistant construction is quite feasible without any substantial increase in initial construction costs.
The timber industry and the manufacturers of various types of wood fasteners have long recognised the need for special fasteners to provide a more superior anchorage of members. Special structural wood fasteners have been developed and tested which serve the purpose of tying all building components together.
The fasteners consist of metal shapes which are pre-punched for easy nailing and their proper use results in increased shear resistance of the wood building components.
The industry has the necessary technology to build in a storm-resistance manner. This knowledge is now available to everyone involved in the building industry.
The necessary educational efforts will result in improved building practices for residential construction and repair which have not been required nor specified in the past.
Cyclonic winds usually are not damaging to structures, except windows and roofing, until the wind velocities exceed 160 kph. The most severe damage is cause when foundations fail, or when the structure is torn loose from its foundation.
The next more severe damage results from roof failures, caused by improper tries between the structure and the roof. Even where walls are well constructed and only the roof goes, it leaves the interior exposed to heavy rainfall causing major damage to furniture and fixtures.
Not all damage can be eliminated, but a very substantial percentage of it can be avoided with the simple and inexpensive principles that can be applied to building construction.
These principles consist of ensuring that good foundations are provided and that the structure is not only securely tied together but to the foundation as well.
