Australia Weather News

It's mad to think that the humble difference between a nail and a screw played a central part in Darwin's undoing when Cyclone Tracy struck.

It helped set off a domino effect that virtually dismantled every house in Darwin, flattening them like they were made out of cardboard.

More than 60 people lost their lives and those who survived it have lived with the deep scars of the memory.

The most destructive cyclone in Australia's recent history overturned the lives of the people who lived through it.

Fifty years on, it has also fundamentally changed the rule book for building homes in Australia, with every wall across the country showing the fingerprints of Tracy.

But, more pertinently, experts say we are still learning lessons about housing as climate change elevates the risk of natural disasters in Australia.

The night Darwin changed forever

Joy Cardona is one of the tens of thousands of people who spent that fateful Christmas fearing for her life as the city she'd known and loved got torn apart.

At 18 years old, she'd spent the evening of Christmas Eve at a friend's birthday party — blissfully ignorant of just how bad things were about to get.

But when she left the restaurant by 10pm, it was clear something monstrous was looming.

"The wind was howling, the sky was eerie, it was orangey, it was pale, it was grey. It was like a monster movie," she says.

"Then the wind just picked me up because I was very light. Luckily, one bloke grabbed me and pulled me down."

Joy spent the night huddled in her home with her 18-month-old daughter and partner, deafened by the terrifying shriek of metal scraping along the ground.

"The tin roofs were the dangerous ones. They were flying in there like missiles," she says

"I heard this crackling and I thought, 'What's that?'

"And I ran and grabbed my daughter out of the cot just in time when the wind, when her whole bedroom window went flying into her cot — glass was everywhere.

"We knew we were in danger, then."

For thousands of people in Darwin like Joy, nothing would ever be the same after that night.

"Everybody that night prayed as one, one group of people, because you were praying to something," she said.

When daylight came on Christmas morning, Darwin was unrecognisable.

"Like, like an atom bomb had gone off, debris everywhere," she remembers.

"Trees were just uprooted. There was, people crying. There's people who had blood on them, you know. Like, what? What did we just get hit by? What the hell?"

The scenes of the demolished Darwin were something that, 50 years on, have left a mark on cyclone engineer Geoff Boughton, too.

A student at the time, he was based on Croker Island — a remote island 250km north-east of Darwin — which was also impacted by the fierce winds of Tracy, though not to the same extent.

He became part of the crew who stayed to clean up in the aftermath.

"There was nothing left. No trees, no birds, no families, and it was eerily quiet," he says.

"You'd, you'd drive along these quiet, empty, desolate streets and you'd smell something, every time it was either a fridge or a pet.

"Yeah, it wasn't a hoot. It wasn't a fun place to be."

Warnings were ignored

Though the extent of the damage may suggest otherwise, the residents of Darwin had been warned about Tracy.

But it hit Darwin at a time when it was vulnerable, complacent and distracted by the holidays.

Just three weeks earlier, the Bureau of Meteorology (BOM) had predicted another cyclone would hit Darwin but it never arrived — giving many residents a "false sense of security, if not a tendency to disregard negative forecasts", according to a BOM blog.

But even with the perfect amount of immediate pre-cyclone preparation, much of the damage could not have been avoided.

Tracy hit Darwin bang-on.

Its howling winds — measuring up to 217 kilometres per hour before the Bureau's wind equipment broke — crawled through the city at snail's pace, allowing time for it to do its worst.

Sixty-six people died — most killed by flying debris or crushed under their homes.

All communications, power, water and sewerage were cut off.

And 90 per cent of houses in Darwin were damaged to the point they were "uninhabitable", leaving over 30,000 people with no choice but to evacuate.

Joy Cardona and her daughter were sent to Perth.

"It was the saddest, heartbreaking, most devastating thing I've ever had to do," she says.

"I didn't know anything else but Darwin."

It was clear to everyone that something had gone terribly wrong with Darwin's housing.

What emerged from the catastrophe fundamentally changed the way we built houses all around the country.

Tracy changes the rule book

Cyclone Tracy never lost its grip on Geoff Boughton, who is now a senior cyclone engineer with the James Cook University Cyclone Testing Station.

"It was quite some time before I could hear a Christmas carol without tearing up," he says.

"But it also gave me a fire in my belly to improve things for buildings."

He says Cyclone Tracy led to some of the biggest reforms the Australian house-building industry has ever had to face.

And much of it had to do with the "tin roof missiles" that Joy had seen from her bedroom window.

Nearly every house in Darwin lost its roof — particularly when something like a window or door was broken — setting off a "chain reaction" of destruction.

"You think of the houses right at the outside of Darwin, they lose their roofs, they crash into the next row, they lose their roofs, they crash into, you get this snowball of debris," Geoff says.

It was a failure that ultimately came back to the way houses were built at the time.

Until then, most houses in Australia — and elsewhere in the world — were constructed according to rules based on experience.

"The housing industry at that stage was viewed as a craft industry, 'this is the way we build houses, this is what we have to do to stop the roof from falling in,'" Geoff says.

"And not too many builders had paid attention to what we have to do to stop the roof from blowing away."

The strength of materials had also played a role, with many cracking and breaking amid the violent winds.

Within just three months, a long list of recommendations was being filtered into the rebuild of Darwin, to try to stop Tracy's destruction from ever happening again.

One of the most significant changes to building from that point on was that all buildings in Darwin, including houses, needed to be structurally engineered for wind — something only the larger buildings had done up until that point.

"When a window breaks, it doubles the load on the roof, and that was unappreciated before that," Geoff says.

"That was a very significant change in the way we build buildings."

It promoted large-scale training courses to be rolled out around the country to help educate builders about the change.

It even saw a big promotion for the humble roofing screw.

"So, in the past, roofing had been nailed together, and nails you can pull out with a hammer, and so they could be pulled out by the wind," he says.

"Whereas screws lock themselves into the timber and are much, much harder to pull out. That, that kind of detail, a tiny little thing, was really important in holding buildings together."

Fast forward to today, and Tracy's impact has spread far beyond the footprint of Darwin.

Soon after, the changes to building were adopted in other regions at significant risk from tropical cyclones. 

And by the 2000s, the lessons of Tracy were being built into the walls of every house in Australia, thanks to the introduction of the Building Code of Australia — now called the National Construction Code.

"Every single house that is built today benefits from what we have learned in Cyclone Tracy, and a whole bunch of other cyclones since," Geoff says.

The lessons we didn't learn

The swift response to building design in the aftermath of Cyclone Tracy is a testament to the way Australians come together in the face of adversity, according to Geoff Boughton.

Even still, he and others say there is always more we can learn.

James Cook University adjunct professor George Walker, who led the damage investigation of Cyclone Tracy, said it showed how disasters could affect whole communities.

"It was not the death toll that made it one of Australia's worst disasters — by comparison, over 3,500 were killed by road accidents in Australia in the same year and nearly 20,000 died from the COVID pandemic," he says.

"It was the loss of functionality of the Darwin community and the consequent socio-economic impact on its inhabitants and the nation which made it a catastrophe."

Dr Walker says this issue of "community resilience" has still not been addressed in the building standards of today, which are primarily designed to protect life.

However, in June 2024, Commonwealth and State Ministers agreed that "climate resilience" should be included as an objective of the Australian Building Codes Board from 2025, which Dr Walker says is an important step.

"In the 50th year of the occurrence of Cyclone Tracy, it is a fitting response to an unrecognised lesson that in retrospect should have been learned from it," he says.