The European Severe Weather Database (ESWD) as a data resource for severe weather research

Until recently, there was little awareness of the fact that the risk posed by convective severe events exists throughout Europe. In an effort to generate consciousness of the fact that weather does not care for political or cultural boundaries, the European Severe Storms Laboratory (ESSL) started collecting severe weather reports from all over Europe in 2006. It did so building on initiatives by the Italian regional weather service ARPA-FVG, the University of the Balearic Islands, and the European Storm Forecast Experiment (ESTOFEX).

Presently, the ESWD data set comprises well over 60000 quality-controlled reports. The ESWD data collection is carried out at ESSL in partnership with several European weather services, storm spotter organizations and individuals. Since the official start of ESWD operations the ESWD data has been used in over 60 peer-reviewed publications. The topics of these publications range from forecast verification to the evaluation of remote-sensing and nowcasting algorithms, and from climatological studies to historical case studies.

In spite of its success in supporting such research, the ESWD still has an important shortcoming in that the reporting rate varies greatly from country to country. Climatological overviews of severe weather occurrence demonstrate this. Nevertheless, straightforward analyses of the recorded events uncover interesting characteristics of the European thunderstorm climate that have yet to be explained fully. For instance, the data indicates that annual peak in tornado occurrence (northern Europe: mid-summer, southern Europe: fall) lags behind the peak of large hail (late spring to early summer throughout Europe). Another interesting characteristic finding is the strong connection between severe weather and mountain ranges arguably more so than e.g. in the United States. Therefore, a highly relevant field of research must be to identify the orographically-induced mesoscale processes that prepare the environment for the development of severe convection.

In the presentation, we will give a brief overview of ESSL's international data collection efforts and the quality control system. In addition, we will present a preliminary ESWD climatology of tornado and hail events and show a number of applications of the ESWD data.