EuroFlood: a Python library and queryable index for the CEMS satellite-derived flood-depth archive of Europe

Satellite-derived observations of flood water depth support flood model validation and impact assessment, yet the only open continental-scale archive of such observations, the flood-depth maps of the Copernicus Emergency Management Service, is distributed as several thousand raster files whose sole spatial metadata is a coordinate encoded in each filename. This paper presents EuroFlood, an open-source Python library and a published spatial index that make the archive queryable. The index records which events inundated each grid cell, so discovery, recurrence, and footprint queries are answered from a small fraction of the archive volume, while depth rasters are retrieved on demand. It reproduces the archived event footprints losslessly at its grid, and a completeness audit against an independent flood-impact database shows that most documented floods co-occur with archived events. Demonstrations include continental recurrence mapping, comparison of observed with modelled flood extents, and event-based exposure assessment.