Internal structure of giant hail in acatastrophic event in Catalonia(NE Iberian Peninsula)

Abstract

On 30 August 2022, a giant hail-bearing supercell hit Catalonia (NEIberian Peninsula), producing stones 12 cm in diameter. This is the most severeepisode ever recorded in the country. Seventy people were injured, resulting inone fatality; several buildings were severely damaged, which resulted insubstantial financial losses (more than €6M). In the present study, we analyze the stones collected during fieldworkto gather information on their growth processes. This analysis was conductedconsidering two lines of investigation. In this paper we focus on the innovativeand never-before-used technique of the Computed Tomography Scan, whichwas utilized to analyze hailstones and their interiors, the outcomes weregroundbreaking. It makes it possible to obtain a complete 3D view of theinterior of the stone, without producing any alteration in the structure.Through this technology, the different layer densities have been quantified.This is the main novelty of the study and opens a promising door to moreanalyses in this field. The analysis has revealed some interesting results that help to verifyprevious theories. For instance, the nuclei can be placed far from the stonecenter, even if the hailstone is externally spherical. Besides, a thicker hailstone layer in one direction indicates the fallingdirection. Finally, the different layer densities show growth process variations.