‘Silent killer’ heatwave in 2009 a deadly wake-up call for Australia

The streets are deserted. An eerie silence hangs over the suburbs.

More than half a million households have lost power, trains are being cancelled, some rail lines have buckled.

Residents are sheltering in their homes, the blinds drawn. Hundreds of people will die, quietly, behind closed doors.

This is not the start of a post-apocalyptic movie.

Actually, it’s Melbourne in 2009.

In the last week of January, a heatwave settled over Australia’s south-east, locking in endless days and nights of soaring temperatures.

What unfolded over the following two weeks was the deadliest natural disaster in Australia’s recent history. Yet, most people don’t know the full scale of what happened. It was overshadowed by another catastrophe hot on its heels.

Since 1900, heatwaves have killed more people in Australia than floods, fires, and all the other disasters put together.

And with the climate warming, we’re likely going to see more in the future.

This heatwave was really a wake-up call for Australia and a harsh reminder of just how deadly extreme heat can be.

John Nairn was a manager at the Bureau of Meteorology in South Australia in 2009.

“I was a bike commuter to work. And the heat coming off the roads was phenomenal. You really, really didn’t spend much time on those paved areas if you could possibly help it. Even as I rode through the parklands, it was still searingly hot,” he says.

A large high-pressure system parked itself over the Tasman Sea at the same time as there was an intense tropical low and a cyclone spinning off the north-west coast of Western Australia. Together, they funnelled hot tropical air through to the country’s south-east.

“So that’s the worst possible scenario for a heatwave,” Dr Nairn says.

In the first few days, temperatures soared to record highs across large parts of Tasmania, becoming responsible for seven of the eight highest temperatures recorded there at the time.

Parts of South Australia and Victoria reached their highest maximum temperatures in 70 years.

But, as Dr Nairn explains, it wasn’t just the daytime temperatures that made it so extreme.

It was also the nights.

“I often tell people that the minimum temperature is much more important during a heatwave than the maximum,” he says.

“If you’ve got a high minimum, not only do you get little relief overnight, but it does mean that the temperature kicks in earlier in the day and rises to the higher temperature much sooner. And that high temperature will last well after sunset and continue to build.”

 One spot in the northern suburbs of Adelaide got to 41.7 degrees Celsius at 3am.

As the region sweltered, people looked for ways to cope.

Some moved their beds away from the walls that radiated the heat of the day late into the night.

They avoided cooking during the day, and air conditioners were cranked at full throttle in households lucky enough to have one, pushing electricity demand to record highs.

As a result, about half a million households lost power on the evening of January 30, and rolling blackouts were triggered in central and western Victoria.

Melbourne’s transport also withered under the intensity of the heat. On the third day of the heatwave, train tracks buckled as the metal expanded.

A third of the train services had to be cancelled, largely due to the failing air conditioning, exacerbated by the power blackouts.

Even the BOM’s offices in Adelaide were struggling to cope.

Dr Nairn recalls the air conditioner failing, leading to fears that the supercomputer used for weather forecasting was going to shut down.

“Our techs came up with a brilliant solution and they stuck a sprinkler on top of our air-conditioning system so that we could pull in evaporatively cooled air into it before it started to cool it,” he remembers.

Heat and the body

It wasn’t just infrastructure breaking down. The human body can only withstand so much intense heat before it fails under the stress.

Amid the heat, hundreds of people were dying.

Inside Melbourne’s morgue, a cool and clinical space usually detached from the flurries of human activity and the weather outside, more and more bodies were being brought in.

“It’s a slow-burn realisation that the numbers are bigger than they would normally be,” says Rebecca Owen, who was managing the morgue at the Victorian Institute of Forensic Medicine during the heatwave.

“And there’s an awful lot of reports coming from hospitals or vulnerable people, elderly people.

“It wasn’t really until we literally were at capacity that you think, ‘Oh goodness, this isn’t going to go away anytime soon.'”

The morgue was at capacity, with bodies being stored off-site for the first time in its history.

Rebecca Owen and the team were even considering bringing in demountable cool rooms to plug at the car park.

Victorian and South Australian government reports found that the 2009 heatwave contributed to more than 400 deaths.

That makes it the deadliest natural disaster in modern Australian history, according to a 2011 research article published in Forensic Science International.

Extreme heat is often called the silent killer. It’s the deadliest of natural disasters.

According to the UN, 489,000 people die from extreme heat around the world each year, a number expected to rise as the planet warms.

But it doesn’t get as much attention as other disasters.

Part of this is because of the way heat kills.

According to Ollie Jay, a professor of heat and health at the University of Sydney, heat makes the body work harder to stay cool. The body sweats and blood is redirected away from the core towards the skin, putting extra stress on the body’s systems.

“That’s why people with heart disease are at more risk. It’s not because they overheat faster … it’s because the way in which their body is trying to defend body temperature, it places the extra strain on the body, which they can’t cope with,” he said.

As they witnessed in the Melbourne morgue in 2009, heat is especially dangerous for vulnerable and elderly people.

“Above the age of 65 or 75, that ability to sweat is quite blunted. So it means that the amount that you heat up … is going to be much higher,” Professor Jay explained.

Heat can also trigger more deaths due to fatigue, poor mental health and an increase in accidents.

But heat deaths rarely appear on a death certificate.

Instead, heat-related deaths are usually determined by how many extra deaths there were during a heatwave compared to a normal period, in what’s known as “excess deaths”.

The next disaster

There’s another reason why people don’t remember the 2009 heatwave.

On February 7, the final day of the heatwave, temperatures rocketed to record highs across 80 per cent of Victoria, ahead of a large cold front pushing across the country.

Geelong reached 47.4C, while Hopetoun, near the South Australian and Victorian border, hit 48.8C — believed to be the highest temperature ever recorded that far south anywhere in the world.

The cold front whipped up a deadly combination of strong winds and storms on a landscape that was already dry from the heatwave and a decade of drought.

It was the start of the Black Saturday Bushfires.

Whole towns were caught unprepared, trapped by towering flames.

More than 170 people died and thousands of homes were destroyed.

In the news, the heatwave was quickly forgotten as the horrific images of the fires took over front pages.

Melbourne’s morgue was already full.

The heatwave had exacted its toll and now another disaster was underway.

“I think sadly in many ways the bushfires kind of overtook the natural disaster that had happened the week beforehand. The heatwave in and of itself was a real tragedy,” Rebecca Owen reflects.

Preparing for extreme heat

It was an alarming wake-up call for Australia’s authorities, and since then Dr Nairn has watched as other countries have gone through the same.

In the years since, his work has focused on extreme heat, at the Bureau of Meteorology and later with the World Meteorological Organisation.

“The general story around the globe is until you’re really smacked in the face by one of these events, you’re probably not motivated sufficiently to actually change your systems and get ready for it,” he says.

Australia’s heatwave response has changed significantly since 2009.

There is now a national heatwave warning service, triggered based on temperature thresholds in the area, day and night-time temperatures, and what the usual temperatures have been over the past month.

From there, governments and community groups can enact heat action plans. Telephone centres reach out to vulnerable people with advice, emergency services prepare their responses, and community messaging around heat goes out.

“When we get to an extreme event, you’re actually seeing actions being taken to protect utilities such as power, water, traffic systems, transport,” Dr Nairn says.

Local governments and homeless shelters open up more cool areas for people to shelter out of the heat.

Beyond acute heat events, Australia’s cities are increasingly looking at ways to help reduce the urban heat island effect, which causes cities to be hotter than rural areas because of a lack of green spaces and the way heat gets trapped in built environments.

Melbourne now has “heat officers” who focus on ways to reduce the severity of extreme heat events in the city.