Global Flood Cat

Global Flood Cat is Fathom's global flood catastrophe model. It estimates the financial losses that flooding can cause to individual locations and to whole portfolios of residential, commercial and industrial assets, covering buildings, contents and business interruption. Fathom describes it as the first global catastrophe model to include all major flood perils: pluvial (surface water), fluvial (river) and coastal.

The model has five parts: an event set of millions of synthetic flood events representing 10,000 years of activity; hazard footprints giving flood depth for each event at 30 m resolution; global exposure data on asset values and building heights; vulnerability functions linking depth to damage; and a financial module that produces event loss tables, average annual loss and exceedance probabilities. The hazard comes from Fathom's Global Flood Map, whose terrain corrects the Copernicus DEM, which was acquired by the TanDEM-X radar mission, with machine learning and LiDAR. The river network is built partly from Landsat satellite imagery. Damage uncertainty, including nil and total losses, is simulated by Monte Carlo.

Users can supply their own vulnerability, scale event losses and hazard, and set location-specific flood defences. Since June 2025 the model includes Fathom's Climate Dynamics framework, so losses can be estimated for future climate scenarios. It is Oasis-enabled and uses the OED exposure format. Buyers can run it on catastrophe-modelling platforms such as Verisk Model Exchange and Moody's, run it on premise, or have Fathom run their portfolios as a data service. The UK region is free of charge.