Major flooding in Brisbane, south Queensland and north New South Wales
Ex-Tropical Cyclone Alfred is the seventh named storm of the Australian cyclone season and made landfall along Australia's east coast, significantly impacting southeast Queensland and northern New South Wales. According to Weatherzone (Weatherzone, 2025a), Brisbane experienced its wettest day in 51 years, recording a daily rainfall gauge total of 275.2mm. Over 330,000 homes and businesses lost electricity, with more than 316,000 properties affected in Queensland alone (World Weather Online, 2025). Near Lismore, 13 service personal were injured when two army trucks collided, and one person has lost their life in flood waters near Dorrigo (Guardian, 2025a).On March 9, 2025 the Insurance Council of Australia (ICA) declared an Insurance Catastrophe for southeast Queensland and northern New South Wales (NSW) regions (ICA, 2025a), with over 63,600 claims (ICA, 2025b) being submitted to date.
At the time of writing, JBA estimates the insured loss from Ex-TC Alfred to be in the range of AUD $1.5 - 2.5 billion. Event loss estimates evolve over time as claims are registered and mature. JBA will update this estimate as appropriate as more information about the event emerges.
Meteorological overview
The Bureau of Meteorology (BoM) has predicted the 2024-2025 cyclone season to be in line with long term records, however the likelihood of severe tropical cyclones to be higher than average, due to seasonal forecast of above average sea temperatures as seen in Figure 1 (BoM, 2025a).
Alfred developed from a tropical low detected initially in the Coral Sea on 20 February, off the north-east coast of Australia (Weatherzone, 2025b). This disturbance was related to a monsoon trough, a weather pattern which can spawn multiple cyclones, in this case Alfred, Seru and Rae. While unusual to spawn three, it is not unprecedented with the last occurrence in 2021 and TCs Lucas, Ana, and Bina (Britain Herald, 2025). Alfred was fuelled by sea surface temperatures almost 1°C above the long-term average for the time of year (INKL, 2025).
On 22 February, Alfred became a Category 1 cyclone, building over a few days to Category 4 (27 February), before undergoing an eyewall replacement cycle, leading to fluctuations in intensity. By March 1, it had weakened to Category 1 (Guardian, 2025b). Alfred then exhibited an unusual track. Typically, tropical cyclones in the Coral Sea are steered south eastward away from Australia by prevailing upper-level winds, curving out to sea under the influence of mid-latitude westerlies (The Times Of India, 2025). Initially Alfred did follow this track but then deviated sharply and headed back toward the coast of Australia on 4th March, deflected by a ridge of high pressure to the south (NASA Earth Observatory, 2025). This placed Brisbane and parts of the Gold Coast directly in the storm’s path.
The forward-speed of Alfred towards the coastline was slow and resulted in a delayed landfall with the storm remaining offshore for several days as seen in Figure 2. As it approached the Australian mainland, Alfred further weakened and was downgraded to a tropical low before finally making landfall between Brisbane and Maroochydore on March 8, 2025 (Guardian, 2025b). This stalling effect resulted in a more prolonged period of impact from a variety of hazards with flooding from rainfall and elevated sea levels, as well as strong winds. Alfred continued to deposit significant rainfall through to 10 March. After making landfall, Alfred quickly lost energy as it had moved out of the latitudes which would typically sustain a tropical cyclone (Brisbane itself is sub-tropical).
Even though Alfred had reduced to a tropical low upon landfall, it brought along high volumes of rainfall across Queensland and NSW, with records showing a peak on 10 March 2025. While most recorded rainfall show return periods lower than 10, some stations show higher exceedance probability, like Nimbin Post Office at 500-year probability and Brisbane Road and Franklyn Vale at 300-year probability (Figure 3).
JB Pacific's Flood Forecasting System
JB Pacific's Flood Forecasting System uses Delft-FEWS, which is an open data handling platform designed for building tailored hydrological forecasting systems. The system allows the integration of large datasets, provides specialised modules to process the data and is fully automated. Delft-FEWS manages the entire automated forecasting process which utilises the following data:
- Recorded rainfall and water level gauge data
- Official Bureau gridded forecast rainfall products – Australian Digital Forecast Database (ADFD)
- Nationally modelled soil moisture – Bureau Australian Water Resource Assessment – Landscape (AWRA-L)
- Simulated hydrologic forecasts from URBS (Unified River Basin Simulator)
- Established warning thresholds
The Forecasting System takes the 7 previous days of observed rainfall and the next 7 days of forecast ADFD rainfall. The flows are then applied to rating curves to get forecast flood levels. These flood levels are then used to indicate the severity of a forecasted flood by identifying whether a flood level will cross the minor, moderate or major threshold.
From observed real-time gauge data, the Albert River recorded approximately 400mm as a basin average over a 5-day period, from 5 March to 10 March 2025. In the afternoon of 7 March, hours before the anticipated landfall of Tropical Cyclone Alfred, basin average forecast rainfall totals processed from the ADFD product ranged from approximately 130mm to 600mm for a period of 7 March to 10 March, as shown below.
As shown in Figure 4, the basin average cumulative rainfall for the Albert River catchment closely resembles the rainfall totals of the ADFD 25th percentile forecast, whereas the temporal variability varies reasonably. Temporal and spatial variability across the catchment is shown by the individual station plots of Wolffdene, Benobble, and O’Reilys. The Wolffdene water level gauge peaked at the Major Flood Classification on 10 March, which was followed by the peak daily rainfall of 289mm. The Beenleigh gauge peaked shortly after on 10 March, exceeding the Major Flood Classification. It recorded a peak daily total of 225mm – as shown in Figure 5. This would suggest that the areas surrounding these sites were either at high risk or impacted by fluvial flooding.
Event impacts
Residents in south-east Queensland and northern NSW have borne the brunt of the now ex-Tropical Cyclone Alfred. Flood warnings were issued for residents in Brisbane, Logan, Gold Coast and Ipswich. The Ipswich city council issued an emergency alert as the city was inundated by flash flooding and the overflowing Bremer River (Guardian, 2025c). Further west, the Laidley creek in Lockyer Valley broke its banks and brought extensive flooding to over 4000 residents (ABC News, 2025a).
In northern New South Wales, 20,300 people were told to evacuate as 80 to 110 millimeters of rain poured over major towns including Lismore and Coffs Harbour (ABC News, 2025b) (Guardian, 2025c). The State Emergency Service (SES) conducted multiple flood rescues, responding to over 1,100 incidents within 24 hours (ABC News, 2025c). A 61‐year‐old man was swept away in floodwaters near Dorrigo, marking the first fatality, while a major road incident involving Australian Defence Force vehicles near Lismore injured 13 personnel (Reuters, 2025).
Critical infrastructure suffered significant damage. Wind gusts over 100 kilometers ploughed through the east coast, which downed power lines for more than 300,000 properties in both Queensland and northern New South Wales (ABC News, 2025d) (CNN, 2025) Significant coastal erosion has been identified from the Sunshine Coast down to mid-north NSW (Guardian, 2025d).
Parts of the Fraser Coast, measured more than 300 mm of rain on 9 March, triggering flash flooding. An exclusion zone was put in place with residents of Hervey Bay ordered to remain indoors. On that day 155 emergency calls were logged, leading to extra crews being sent to the region and multiple rescues from vehicles and properties (ABC News, 2025e).
Insurers have received over 63,600 claims to date (13 March) and expect more as residents return home to assess the full extent of the damage (ICA, 2025b). S&P Global Ratings originally pencilled in insured losses of $2 billion, however due to the downgrade of Alfred to a low depression, previous concerns about a high number of severe wind damage claims were not realised. This resulted in claims being related mainly to flooding and storm-related water damage. Most claims – over 58,500 - were in the state of Queensland, of which 54,000 impacted residential properties (ICA, 2025b). This follows very quickly on the back of severe flooding in Townsville in late January (JBA, 2025).
Notable historical events
Historically, southeast Queensland and northeast New South Wales have experienced significant floods from extreme rainfall, monsoonal systems and tropical cyclones. There have been a sequence of high severity floods impacting the eastern coast of Australia in recent years, notably in 2010-11, 2017, 2022, 2023 and ongoing floods in 2025. Below is a summary of notable flood events:
Climate change
The relationship between tropical cyclone activity and climate change is complex, and attributing the behaviour of individual storms to climate change is a relatively new, albeit growing, field. However, some aspects of Alfred’s behaviour are consistent with climate change projections. Out-of-zone events such as Alfred may become more frequent. A report by the Australian Academy of Science warned that continued global warming and increase in mean sea surface temperatures will likely expand the zone of cyclone vulnerability southward, meaning areas like Brisbane and the Gold Coast could face tropical cyclones more often in the future (Tempests and Terawatts, 2025). This is consistent with the IPCC’s findings of a poleward shift in cyclone intensity distributions and an increase in the frequency of the most intense storms (IPCC, 2023).
Australia Products – Inland Flood Model and Coastal Flood Maps
All loss estimates presented in this report are generated from JBA Risk Management’s new Australia Inland Flood Model which includes fluvial and pluvial flood perils. In addition to our comprehensive river and surface water flood maps (with 5m resolution in major cities ), we also have coastal flood mapping for Australia.
This report is accompanied by a flood footprint for the event, detailing extents and depths of the flooding in areas affected in North Queensland. Download it via our Client Portal or request a copy by emailing eventresponse@jbarisk.com.
