What is storm surge?

Storm surge is primarily triggered by tropical cyclones, hurricanes or intense low-pressure systems with strong winds. Its severity depends on storm intensity and speed, as well as the shape of the seabed and coastline.

Strong winds push seawater toward the shore, while lower air pressure at the storm’s centre slightly elevates the sea surface. The shape of the coastline and the sea floor (bathymetry) influence storm surge. Shallow, funnel-shaped bays amplify storm surge, while steep coasts lessen its effect.

Storm tide occurs when storm surge combines with the regular high tide, resulting in greater coastal flooding and accelerated dune erosion for several hours.

Not all coastal floods are caused by storm surge. Coastal flooding can also result from heavy rainfall, overflowing rivers or tsunamis.

Climate change is expected to worsen storm surges by:

Storm surge can contaminate freshwater sources and farmland and endanger lives, especially where evacuation is difficult. In severe cases, it can result in fatalities and long-term displacement of communities. Even without an increase in storm frequency, the severity and impact of each event are likely to intensify.

In the Asia-Pacific region, modelling suggests that cyclones may become less frequent but more intense, with a broader geographic range — retaining tropical or extratropical characteristics further from the equator. This shift highlights the need for adaptive planning, as even fewer storms could have greater destructive potential.

Low-lying coastal areas are vulnerable to storm surge, with risk increasing due to limited protection infrastructure and high population density.

Globally, regions vulnerable to storm surge include Bangladesh, the Philippines, Pacific Island nations, the Netherlands and the United States Gulf Coast (Louisiana, Mississippi, Florida) and Southeast. In Australia, northern areas such as the Gulf of Carpentaria, the Coral Sea coast of Queensland, and the Northern Territory are especially at risk due to frequent tropical cyclones.

Here are some examples:

Forecasting storm surge relies on advanced computer models that simulate the interaction between storms, ocean conditions and the coastline.

Advanced modelling and hazard mapping enable accurate prediction of storm surge extent, identification of vulnerable areas and effective evacuation planning. By simulating water levels in response to wind, atmospheric pressure and tidal changes, these models present clear scenarios of potential flooding.

Mapping outputs translate complex data into actionable guidance for planners, emergency managers and communities.

Engineers use surge data to design safer structures while local governments apply hazard maps to planning controls. Clear visuals and community engagement raise awareness, helping people understand their risk and prepare proactively.

Reducing the impact of storm surge involves a comprehensive, multi-layered approach that combines engineering, nature-based solutions, policy planning and technological considerations. Each strategy plays a critical role in enhancing coastal resilience:

This overarching strategy integrates modelling, risk assessment and community engagement into a place-based framework that balances protection, retreat and accommodation. It aligns infrastructure investments, land use decisions and community planning with evolving coastal risks. By embedding resilience into development pathways, adaptation strategies help communities thrive amid changing climate conditions.

We collaborate with governments, communities and industry to manage storm surge risks by delivering advanced flood modelling, designing resilient infrastructure and developing comprehensive climate adaptation strategies. With extensive technical experience and deep local insight, we empower decision-makers to minimise risk and strengthen coastal resilience.

For example, the Hinchinbrook Coastal Hazard Adaptation Strategy (CHAS) demonstrates effective local solutions to complex coastal hazards across present-day, intermediate and 2100 horizons.

Through hazard mapping, scenario modelling and strong community engagement, CHAS can be used to identify vulnerable areas and shape land use, infrastructure and emergency planning. By integrating engineered and nature-based measures, adaptive policies and public education, our work has helped deliver targeted mitigation for the Hinchinbrook region.

Protecting vulnerable assets and guiding long-term planning also require funding and navigating permitting processes for coastal resilience projects. Coastal resilience is a collaborative opportunity to safeguard communities and natural heritage.