Satellite flood mapping uses radar and optical imagery to outline where water is after an event; the same approach maps burn scars after wildfire and damage after storms. Overlaid on an insurer’s or lender’s exposure, those layers become geospatial risk signals: which insured locations are likely affected, and which need a person to look first.
Radar is the workhorse because floods come with cloud, and Sentinel-1 sees through it. Public rapid-mapping services such as the Copernicus Emergency Management Service publish event maps for major disasters; the gap is joining them, and your own analysis, to your policies or assets quickly and consistently. These signals complement a catastrophe model, they do not replace one, and a claims handler or underwriter makes every decision.