In January this year, a freak hailstorm hit Maldon and surrounds, bringing billiard ball sized hailstones causing distress to livestock and damaging roofs, windows and cars.

The largest reported hailstones fell in Maldon, with some of them exceeding 70 mm in diameter and exhibiting unusual shapes. The shapes and sizes made them of great interest to hail researchers.   

The Bureau of Meteorology came and collected 21 of Maldon’s hailstones for analysis and the subsequent scans and cross-section pictures now live in an international hail library used by researchers to improve models that forecast thunderstorms. 

Joshua Soderholm from the Bureau of Meteorology says, “The knowledge we’re building from hailstone collections allows us to factor in the effects of complex shapes into radar estimates of hail size while also improving our capacity to model hailstones.”

The analysis involved taking a 3D scan of each hailstone in order to accurately record the shape, after which the hailstones were cut open to extract a cross-section and examine the growth rings.

“The information from the Maldon hailstones has become part of a global library of digitised hailstones. We use the 3D shape to better understand how the aerodynamics and fall speeds change as they grow larger. Large hailstones often form unusual shapes. And the growth rings from hailstone cross sections provide a record of the conditions of the storm in which the hailstones developed.”

This work benefits thunderstorm forecasting in the hours to minutes leading up to impact. 

This article appeared in Tarrangower Times, 9 June 2023.

Related story: Hailstorm damage in Maldon