Using 3-D Laser Scanning Technology to Create Digital Models of Hailstones

The emergence of 3-D scanning technologies has provided an exciting opportunity to explore the shape characteristics of hailstones in great detail. This new ability to effectively characterize the shape of hailstones will improve the understanding of hailstone aerodynamics as they fall, which will lead to improvements in terminal velocity and kinetic energy relationships with hailstone size. It will also help determine how hailstone density relates to their strength. The information can ultimately be applied to improve risk and loss assessment of hailstorms and contribute to ongoing research to determine ways to mitigate the effects of hail, which accounts for over $1 billion in annual insured losses.

            The use of a hand-held laser scanning system was explored during field campaigns in 2015 and 2016. Hailstones were collected following the passage of intercepted thunderstorms and were measured, weighed, and scanned.  The first successful digital hail model was produced from a hailstone collected near Atchison, Kansas in the fall of 2015. It is believed this is the first time such a system has been used to create digital 3-D models of actual hailstones. During the 2016 field effort, the system was successful in capturing over 60 models of natural hailstones. A full scan takes approximately three minutes to complete and data are captured at a resolution of 0.088 cm. The 3-D model produces highly accurate dimension and volume measurements and is a non-destructive method. Hailstones were subjected to compressive strength testing in order to quantify the relationship between bulk density and strength. In addition to producing accurate volume assessment, these data can be used to 3-D print hailstone shapes to explore their aerodynamics, produce cavity molds for ice impact tests, and to model radar cross-sections of natural hail.