Evolution of the HANZE flood impact database and preliminary results for 1870-2025

HANZE (Historical Analysis of Natural Hazards in Europe) is a publicly available database that brings together information on flood events and their impacts in Europe. The initial version of the database was created in 2017, and two updates have been published since then.

The current version of the database (HANZE v3 beta) contains 2,687 records of flash, river, coastal and compound floods (1870–March 2025). This is over 1,100 events more than in its original version, which covered the time range from 1870 to 2016. At the same time, since the release of HANZE v2, the spatial coverage of the data has been expanded from 37 to 42 European countries.

The database contains the location (using the European Union’s Nomenclature of Territorial Units for Statistics – NUTS level 3), time and quantitative data on the impacts of past floods. Each of the implemented updates has also included changes in the NUTS classification, up to the current 2024 edition. Information on events was obtained from a variety of sources, including scientific publications, international and national disaster databases, government reports, and news reports. The qualification of a flood for the database was determined by meeting at least one of the following criteria: (1) an area of at least 10km² was flooded; (2) at least one person died; (3) at least 200 people or 50 households were affected by the flood; (4) the value of the losses was at least 1 million euro.

The next update, which is currently being prepared, will include data up to the end of 2025. New elements will also be introduced, such as recording flood event type using the 2025 Hazard Information Profiles (HIPs), developed by the United Nations Office for Disaster Risk Reduction and the International Science Council. Annual updates of HANZE are planned, which will be accessible through the European Commission’s Risk Data Hub (https://drmkc.jrc.ec.europa.eu/risk-data-hub) and the HANZE website (https://naturalhazards.eu/). The current work is part of a larger update that will include windstorms and wildfires, which will be used to update the database on attribution of floods to climate and socioeconomic change.

In this contribution we present the recent and future updates in the structure and data collection process in HANZE, as well as discuss the spatial and temporal distribution of floods and their impacts in Europe between 1870 and 2025.