Physics-Based Damage Assessment: Integrating Atmospheric Science with Building Material Thresholds

This paper examines the scientific basis for physics-based hail damage assessment, integrating atmospheric science, hailstone microphysics, and building material response. Traditional hail damage assessment relies primarily on reported maximum hailstone diameter, treating all hailstones of a given size as equivalent. This approach ignores substantial variation in hailstone shape, mass, terminal velocity, and kinetic energy that results from differing atmospheric conditions during hail formation. The paper reviews the Laurie (1960) kinetic energy framework, synthesizes modern research including the Heymsfield et al. (2018, 2020) terminal velocity studies and Shedd et al. (2021) shape analysis, and evaluates the role of CAPE and atmospheric sounding data in estimating hailstone mass and impact energy. The SPEAR Index (Sperling Peril Evaluation and Rating) methodology is presented as a physics-based framework for damage threshold assessment validated against six independent insurance claims across five states.