Hail events in Germany: rare or frequent natural hazards?

Abstract. Hail represents a natural hazard in Germany and has potentially substantial economic and environmental impacts, but it often receives less attention than other weather phenomena. This, combined with the very local nature of hail, results in a lack of observations and further analysis. This study investigates hail characteristics across Germany using crowdsourced observations since 2000 and weather radar data from a 6-year period. A study using 3D printed hailstones provided insights into human perception of hail sizes, revealing that collective crowd estimates closely approximate actual measurements, though individual estimations can vary significantly. By deriving hail proxies out of radar data we analyzed hail frequency, spatial distribution and size variations. Our research reveals a gradient in hail occurrence, with southern Germany experiencing substantially higher hail probabilities compared to northern regions. Mountainous areas demonstrated increased hail frequency relative to lower-elevation territories. June emerged as the peak month for hail events, characterized by both highest frequency and largest hail sizes. This research contributes to a better understanding of hail as a natural hazard in Germany, providing valuable insights for risk assessment, insurance purposes and public awareness.