Storm; Storm;

Storm Surge Inundation Risk Tool, Australia

Stay or go? Helping coastal communities decide what to do in a state of emergency

Storms present risks to any coastal community and in Australia, it’s a very real concern with around 80% of the population living within 50kms of the coast, and sea levels predicted to rise and erratic weather patterns to increase.

For people in buildings such as schools, nursing homes or hospitals, evacuations are often used as a last-minute safety measure. However, they are disruptive, stressful and costly and may not always be necessary.

Arup is creating a real-time, web-based tool to better predict the risk of a flood to buildings and communities. The aim is to give greater confidence to those who must make the difficult judgement call in an emergency – stay or go?

It’s being developed through funding from our Research programme. Originally conceived as a response to the damage caused to Cairns Hospital by tropical cyclone Yasi in north-east Australia in 2011, it is now being scaled to help all coastal communities.

Protecting lives and livelihoods

Yasi was one of the most powerful cyclones to ever hit the state of Queensland. Some 30,000 people were evacuated from Cairns, including 356 patients, relatives and staff from the Cairns Hospital, with many airlifted to Brisbane. While the aftermath of Yasi was devastating, the hospital property itself fared reasonably well. In fact, had better data been available, the evacuation — and the cost and tremendous stress it placed on the evacuated and staff — could have been avoided.


We built a digital tool to help the emergency response managers at Cairns Hospital predict when, and to what extent, their hospital might be inundated from cyclone-induced flooding in the future. They can now make the decision to evacuate or not with much more confidence. ”

David Dack David Dack Associate

Weather events related to climate change are predicted to become more common. This is especially true in the tropics — the region predicted to be one of the most climate-affected in the world.

Assessments in Australia estimate more than $226 billion in commercial, industrial, road, rail and residential assets are exposed to potential flooding. The annual cost of flooding on these communities is estimated at $900 million and is projected to double within the next 10 years. Tools such as those being developed by Arup can help mitigate their impacts.

Scaling the tool to help more coastal communities

Arup is scaling the method developed for Cairns Hospital into a real-time, web-based tool that can be used by all coastal communities vulnerable to storm surge. The team is also looking to test the tool on other types of critical infrastructure in coastal environments, such as power stations and airports. 

To date, the Storm Surge Inundation Risk Tool has been using freely available data from the Australian Bureau of Meteorology. 

Arup is investigating linking it to a real-time predictive hydrodynamic model which would automatically estimate the storm surge at a specific location. This version would also allow automated alerts to be sent to for example, the hospital, when a certain risk level has been reached for inundation. 


Instead of relying on building managers to input weather data, we wanted the tool to automatically suck information from a model running in the background. This means we can get the essential information right when they need it to make that daunting, time-pressured evacuation decision. ”

Ed Rowe Ed Rowe Engineer, Transport and Resources

Storm Surge also weighs factors like a building’s elevation, its main access routes and the kind of forces it can withstand, against climate data to predict the likelihood of an asset being inundated.

The tool is not intended to actually deliver evacuation advice: it will provide the data that can be used in part to make the evacuation decision. The acceptable level of risk must always be defined by the facility owner’s risk management strategy, plans and registers.

The team behind this tool combines the skills of Arup’s user experience designers and software developers within Digital, as well as Maritime, Civil and Structural Engineering

Storm Surge meets Hazard Owl

Although Storm Surge has been created as a standalone tool, Arup is investigating its integration in to  Hazard Owl - the first tool we built to monitor assets against natural hazards. Hazard Owl taps into many data streams, like earthquake registers and weather forecasts, and compares these against  records of what the nearby infrastructure can withstand. When a 6.4 magnitude earthquake rocked Taiwan in 2016, an early version of Hazard Owl assessed 40 nearby buildings within minutes against the likely forces incurred from the earthquake, and let owners know about the risk to their assets.

More information is available in the Research Review publication