Earlier this month, Cyclone Alfred struck the Gold Coast and Brisbane, bringing the predicted heavy rain, flooding, and strong winds. While we've seen the devastating before-and-after images, we wanted to analyze the impact using satellite imagery.
The results were striking, our analysis revealed that the coastline receded by 50 meters after the storm - looking at a ‘before’ December 2024, and after the storm hit Mooloolaba Beach in Feb 2025. We identified a high exposure area, which based on historical erosion rates was relatively more susceptible to significant erosion when the storm hit - e.g it was at greater risk of “increased severity & frequency”.
Here’s how we did it:
1. Pre-storm: Landsat (30 meter resolution).
2. Post-storm: Integrated non-cloudy imagery (Sentinel 2, 20 meter resolution) only for 2025-03-04, the first image available.
3. All tidally corrected, to ensure we are not capturing ‘false’ shoreline retreat or advancement.
In terms of the storm’s financial impact, insured and economic losses amounted to an estimated hundreds of millions of Australian dollars due to the high exposure of the affected areas, according to Aon. Interestingly, the area is not covered by cat bonds to which Icosa Investments AG shared some thoughts: ‘Whilst being significant in local terms, Tropical Cyclone Alfred is unlikely to cause losses that would have a wider impact on the capital balance in reinsurance markets.’
