From impact data to impact-based warnings: developing an impact-centred database to support local warning validation

Despite major advances in the accuracy and lead time of hydrometeorological forecasting, significant gaps persist in the early warning-early action chain, limiting the ability of warnings to trigger timely and effective protective actions at the municipal level. Impact-based early warning systems have emerged as a promising pathway to address these gaps; however, their operational implementation, particularly the systematic availability, integration and usability of impact data for warning validation and improvement, remains a key challenge.

In this contribution, we present an impact database environment designed to collect, structure and support the analysis of observed impacts from hydrometeorological events. The database links reported impacts to forecasts, warning levels and predefined response actions, and is dynamically populated through a mobile application that enables users to submit geolocated impact reports, including text descriptions, images and links to official information sources. A central component of the database is its connection to in situ sensors, forecasts and warning thresholds, enabling comparisons of observed impacts with forecasted conditions and triggered warning levels to support warning validation and refinement. In parallel, artificial intelligence techniques are being integrated to support the organisation and filtering of incoming impact reports, and to explore the extraction of event-based impact information, with the aim of informing future impact-based warning threshold assessment.

This impact database ecosystem is embedded within the Site-Specific Early Warning System (SS-EWS) architecture, an operational framework for designing and implementing impact-based warnings at vulnerable locations to trigger self-protection actions. The SS-EWS, including the database prototype, is currently being implemented, improved and evaluated in close collaboration with civil protection and emergency authorities across vulnerable municipalities in Europe within the Horizon Europe GOBEYOND project, and in Catalonia (Spain) through the SAAI project, providing a broad co-design and real-world evaluation environment.