Författare: Steve Turton Adjunct Professor of Environmental Geography CQ

Severe Tropical Cyclone Zelia is bearing down on the northwest coast of Australia and is likely to make landfall early Friday evening.

It’s a monster storm of great concern to Western Australia. Port Hedland is the largest town in the firing line and also our busiest iron ore export port. Strong winds may extend to other areas along the coast, and inland to areas such as Marble Bar, Tom Price and Paraburdoo.

Even if Zelia doesn’t hit towns directly, it’s likely to cause a lot of damage. The Bureau of Meteorology predicts extremely dangerous sustained winds of around 205 kilometers an hour and wind gusts higher still, at 290km/h. That’s strong enough to flatten homes, trees, power lines and other infrastructure.

This is a category five cyclone, which is the most severe possible under the current scale. But as climate change worsens, authorities may need to add another category to the scale.

Bureau of Meteorology video explaining the threat of Tropical Cyclone Zeila.

Do we need a category 6?

Elsewhere in the world, tropical cyclones are called hurricanes or typhoons.

The severity of a tropical cyclone (or hurricane or typhoon) is ranked in categories from 1 (weakest) to 5 (strongest).

Category one involves maximum average wind speed of up to 88km/h, and strongest gusts up to 125 km/h. It typically causes negligible damage to homes but may damage crops, trees and caravans.

Category five, the most severe, is defined as “extremely dangerous”, causing widespread destruction of buildings and vegetation. These cyclones bring maximum average wind speeds greater than 200km/h and gusts greater than 279km/h.

However, on a warming planet, cyclones are expected to become more intense. It’s also making tropical cyclones and hurricanes intensify more quickly.

Some scientists have called for a category six for hurricanes, typhoons and cyclones with sustained wind speeds greater than 309km/h. They argue a new category is needed to communicate the risks associated with tropical cyclones fuelled by climate change.

Bureau of Meteorology video explaining the threat of Tropical Cyclone Zeila.

Climate change is feeding storms

It’s too early to say if Cyclone Zelia is directly caused, or fuelled, by climate change. However, research over the last 30 years has found a link between global warming and more intense tropical cyclones.

Globally, 2024 was Earth’s warmest year on record. Ocean heat content is increasing around most tropical seas, and other places where tropical cyclones are forming.
Warmer oceans, and a warmer atmosphere, both feed energy into tropical cyclones, making them more intense and fast-forming when conditions are favourable.

Zelia intensified from a category one into a five in just over 24 hours.

Australia is currently experiencing record-breaking sea surface temperatures. The area off the northwest coast has been up to 4-5°C above normal this summer.

Hurricane Milton, which struck the United States in October last year, also shows how climate change is making tropical cyclones worse. Amid very warm ocean temperatures, it intensified rapidly over the Gulf of Mexico to a category five hurricane.

We can expect more of these severe cyclones in future, if humanity keeps warming up the oceans and the atmosphere.

Hurricane Milton struck the United States in October last year.
Rebecca Blackwell/AP

Slow is not good

Climate change is slowing the forward motion of tropical cyclones over the ocean and land. That means they take longer to cross the coast and pass through an area – inflicting more damage from wind and storm surge, and dumping more rain.

The Bureau of Meteorology says Cyclone Zelia’s “forward speed” is quite slow, at 11km/h. So, heavy rain and the strong winds will persist for quite a few hours before and after it crosses the coast.

The strongest winds of a tropical cyclone are usually near the eye, but can extend for hundreds of kilometres. Sometimes, winds on opposite sides of the eye blow in different directions, causing destruction on the ground which damages buildings, infrastructure, farmland and the environment.

Conditions on the ground

At the moment around Port Hedland, winds are about 70-100km/h and rising. That’s gale force but not too alarming. Conditions will rapidly deteriorate into this afternoon, particularly to the east of Port Hedland.

The storm has already dropped a lot of rain. This has caused local flooding and cut rail lines. But there’s more to come.

The Bureau of Meteorology is also warning of a significant storm tide – when sea levels rise well above a typical high tide. This may lead to flooding and inundate coastal roads and properties.

The cyclone will continue to trek inland over the weekend, gradually weakening as it goes. People in mining and Indigenous communities hundreds of kilometres inland could experience strong winds, heavy rain and flooding.

The bureau is providing regular updates online. For those in the path of the cyclone visit www.emergency.wa.gov.au or download the Emergency WA app for the latest community alerts and warnings. Läs mer…

Record-breaking floods across north Queensland have now turned deadly, with one woman drowning while being rescued on Sunday morning. And the floodwaters are still rising, with rain set to continue.

Over the 48 hours to Sunday, there were reports of up to 1 metre of rainfall in parts of northeast Queensland. The torrential rain continues, particularly in the Herbert Coast region and north to around Tully.

Major flooding in northern Queensland rivers, as of 12.45pm February 2.
Bureau of Meteorology

Residents of Ingham and nearby towns, about 100km from Townsville, are witnessing flooding from the nearby Herbert River. This morning, it was at 15 metres and rising. With more heavy rain forecast for the next 24 hours, the Herbert River is likely to break the 1967 record of 15.2 metres later today.

Queensland Premier David Crisafulli – who grew up on his family’s sugar cane farm in Ingham – has said the floods will be a “once in a century” event for the town. To make matters worse, authorities say the town has lost power and an extended outage is likely.

The atmospheric factors behind these floods are very similar to recent floods in the region – and climate change is no doubt playing a role.

The flood level for the Herbert River at Ingham set in 1967 was 15.2 metres. It’s likely to be breached this afternoon (Sunday February 2).
Australian Bureau of Meteorology, CC BY

Where are the floods hitting?

For many people in Townsville – the largest city in Northern Australia – the unfolding emergency will bring back memories of the devastating February 2019 floods, which caused A$1.24 billion in damage. Residents have been asked to evacuate from several low-lying suburbs which were inundated in 2019.

Authorities in Townsville asked all residents in the low-lying black zone to evacuate by midday Sunday February 2. Floodwaters could reach second-storey heights in this zone. Residents in pink suburbs have been asked to be on standby.
Townsville Council, CC BY

It is too early to say if this flood event will be worse. Fortunately, water levels in the city’s Ross River Dam are much lower than 2019. Townsville Airport has recorded 545mm of rain over the past 48 hours, with many northwest suburbs recording much higher levels. The township of Rollingstone – 60km northwest of Townsville – recorded a whopping 702mm over the 24 hours to 9am Sunday.

Further north in the Cairns to Daintree region, residents are watching with concern, with many still raw after the record-breaking floods of December 2023.

In February 2019, floods devastated parts of Townsville. Insurers put the cost at A$1.2 billion.
Dan Peled/AAP

What’s behind these floods?

The ongoing 2025 extreme rainfall event, the 2019 Townsville floods and the 2023 Cairns and Daintree floods are remarkably similar in many ways.

What triggered each of these floods was prolonged heavy rain falling on the southeast flank of a stationary tropical low weather system. Normally, tropical lows bring wind and rain, but move through quite quickly. But in recent years, we have seen a tendency for these systems to stall, sitting in place over or near land and dumping huge volumes of rain.

Last week, the Bureau of Meteorology warned that five tropical lows were forming around northern Australia. Most tropical cyclones form from tropical lows embedded in the region’s monsoon trough, a large low pressure band which forms over summer and draws in warm, moist air from the adjacent tropical seas.

But significant rain events like this one don’t necessarily require a tropical cyclone. Slow-moving deep monsoon lows over land can also deliver huge amounts of rain and widespread flooding.

These atmospheric conditions allow intense rain bands to form between converging winds: warm, moist winds from the northeast and southeast winds originating from the Coral Sea. As the winds collide, they push the moist air up into the cooler parts of the atmosphere where it condenses and falls as torrential rain.

More extreme rainfall and higher frequencies of flooded rivers and flash floods around the world have a clear link to climate change and ongoing global heating.

The main drivers behind these events include warming of the atmosphere. For every 1°C of warming, the atmosphere holds 7% more water vapour. Recent research suggests this figure could be even higher for short duration rainfall.

Hotter oceans hold more energy, meaning they can also amplify the global water cycle when atmospheric conditions are suitable.

This year’s latest ever monsoon

This year, sea surface temperatures in the northwest Coral Sea are 1-2°C above average. Ocean temperatures have risen because of a lack of cloud cover and rain last month. In northwestern Australia, this has given rise to an intensifying marine heatwave.

Residents filling sand bags at Lou Lister Park, Railway Estate in Townsville, Saturday, February 1, 2025.
Scott Radford-Chisholm/AAP

This ocean heat is likely to be driven by the Australian monsoon’s latest ever arrival. The monsoon brings heavy rains to northern Australia, triggering the wet season. When it arrives, sea surface temperatures generally drop due to a combination of high cloud cover and the cooling effect of rainwater.

After a slow start, the North Australian monsoon season is now in full swing.

The Bureau of Meteorology is monitoring an active monsoon trough for any low pressure systems, which may develop into tropical cyclones over the next week or so. If any cyclone does form, it will gain energy from warmer than usual sea surface temperatures.

What’s next for north Queensland?

The flood emergency in north Queensland is far from over. All global circulation models predict heavy rain to continue in the region, extending up towards Cape York and the Gulf Country as an active monsoon surge moves in from Indonesia.

As river catchments get saturated, more and more water will run off and engorge rivers. Forecasts are for rain to continue well into tonight and the next few days. We are likely to see more flooding in more places this week.

For the latest updates, check the Bureau of Meteorology’s Queensland flood warnings, ABC Emergency or local ABC radio stations. Läs mer…

Record-breaking floods across north Queensland have now turned deadly, with one woman drowning while being rescued on Sunday morning. And the floodwaters are still rising, with rain set to continue.

Over the 48 hours to Sunday, there were reports of up to 1 metre of rainfall in parts of northeast Queensland. The torrential rain continues, particularly in the Herbert Coast region and north to around Tully.

Major flooding in northern Queensland rivers, as of 12.45pm February 2.
Bureau of Meteorology

Residents of Ingham and nearby towns, about 100km from Townsville, are witnessing flooding from the nearby Herbert River. This morning, it was at 15 metres and rising. With more heavy rain forecast for the next 24 hours, the Herbert River is likely to break the 1967 record of 15.2 metres later today.

Queensland Premier David Crisafulli – who grew up on his family’s sugar cane farm in Ingham – has said the floods will be a “once in a century” event for the town. To make matters worse, authorities say the town has lost power and an extended outage is likely.

The atmospheric factors behind these floods are very similar to recent floods in the region – and climate change is no doubt playing a role.

The flood level for the Herbert River at Ingham set in 1967 was 15.2 metres. It’s likely to be breached this afternoon (Sunday February 2).
Australian Bureau of Meteorology, CC BY

Where are the floods hitting?

For many people in Townsville – the largest city in Northern Australia – the unfolding emergency will bring back memories of the devastating February 2019 floods, which caused A$1.24 billion in damage. Residents have been asked to evacuate from several low-lying suburbs which were inundated in 2019.

Authorities in Townsville asked all residents in the low-lying black zone to evacuate by midday Sunday February 2. Floodwaters could reach second-storey heights in this zone. Residents in pink suburbs have been asked to be on standby.
Townsville Council, CC BY

It is too early to say if this flood event will be worse. Fortunately, water levels in the city’s Ross River Dam are much lower than 2019. Townsville Airport has recorded 545mm of rain over the past 48 hours, with many northwest suburbs recording much higher levels. The township of Rollingstone – 60km northwest of Townsville – recorded a whopping 702mm over the 24 hours to 9am Sunday.

Further north in the Cairns to Daintree region, residents are watching with concern, with many still raw after the record-breaking floods of December 2023.

In February 2019, floods devastated parts of Townsville. Insurers put the cost at A$1.2 billion.
Dan Peled/AAP

What’s behind these floods?

The ongoing 2025 extreme rainfall event, the 2019 Townsville floods and the 2023 Cairns and Daintree floods are remarkably similar in many ways.

What triggered each of these floods was prolonged heavy rain falling on the southeast flank of a stationary tropical low weather system. Normally, tropical lows bring wind and rain, but move through quite quickly. But in recent years, we have seen a tendency for these systems to stall, sitting in place over or near land and dumping huge volumes of rain.

Last week, the Bureau of Meteorology warned that five tropical lows were forming around northern Australia. Most tropical cyclones form from tropical lows embedded in the region’s monsoon trough, a large low pressure band which forms over summer and draws in warm, moist air from the adjacent tropical seas.

But significant rain events like this one don’t necessarily require a tropical cyclone. Slow-moving deep monsoon lows over land can also deliver huge amounts of rain and widespread flooding.

These atmospheric conditions allow intense rain bands to form between converging winds: warm, moist winds from the northeast and southeast winds originating from the Coral Sea. As the winds collide, they push the moist air up into the cooler parts of the atmosphere where it condenses and falls as torrential rain.

More extreme rainfall and higher frequencies of flooded rivers and flash floods around the world have a clear link to climate change and ongoing global heating.

The main drivers behind these events include warming of the atmosphere. For every 1°C of warming, the atmosphere holds 7% more water vapour. Recent research suggests this figure could be even higher for short duration rainfall.

Hotter oceans hold more energy, meaning they can also amplify the global water cycle when atmospheric conditions are suitable.

This year’s latest ever monsoon

This year, sea surface temperatures in the northwest Coral Sea are 1-2°C above average. Ocean temperatures have risen because of a lack of cloud cover and rain last month. In northwestern Australia, this has given rise to an intensifying marine heatwave.

Residents filling sand bags at Lou Lister Park, Railway Estate in Townsville, Saturday, February 1, 2025.
Scott Radford-Chisholm/AAP

This ocean heat is likely to be driven by the Australian monsoon’s latest ever arrival. The monsoon brings heavy rains to northern Australia, triggering the wet season. When it arrives, sea surface temperatures generally drop due to a combination of high cloud cover and the cooling effect of rainwater.

After a slow start, the North Australian monsoon season is now in full swing.

The Bureau of Meteorology is monitoring an active monsoon trough for any low pressure systems, which may develop into tropical cyclones over the next week or so. If any cyclone does form, it will gain energy from warmer than usual sea surface temperatures.

What’s next for north Queensland?

The flood emergency in north Queensland is far from over. All global circulation models predict heavy rain to continue in the region, extending up towards Cape York and the Gulf Country as an active monsoon surge moves in from Indonesia.

As river catchments get saturated, more and more water will run off and engorge rivers. Forecasts are for rain to continue well into tonight and the next few days. We are likely to see more flooding in more places this week.

For the latest updates, check the Bureau of Meteorology’s Queensland flood warnings, ABC Emergency or local ABC radio stations. Läs mer…