Weather watchers may not realise it, but hailstones are as individual as snowflakes.
Some have menacing points, like the blades of a ninja throwing star. Some resemble the chain-tethered spiky ball on a medieval flail. Others look like discs or doughnuts.
What they are not is uniform, smooth and round.Â
Yet that's what existing models assume when forecasters are trying to work out where hail will fall.
But that's changing thanks to an international library featuring smash hits from around Australia.
Joshua Soderholm is an honorary research fellow at the University of Queensland and a thunderstorm scientist at the Bureau of Meteorology.
He's spent many freezing hours forensically examining more than 100 whoppers sourced under a university program that tracks down giant hailstones from posts people make on social media.
Researchers say hailstones, which come in all shapes and sizes, are carefully measured. (Upplied by University of Queensland/AAP PHOTOS)
Each one has been photographed, 3D scanned, weighed and cut open to allow an examination of their onion-like ice layers.
Those records now sit alongside many others from Canada, China, Germany and the United States and they are making a real difference as researchers work to improve forecasting.
It's hoped within a decade, that data will be routinely factored in to forecasting models.
Dr Soderholm and PhD student Yuzhu Lin, from Pennsylvania State University in the US, have just published a paper that shows the shape of hailstones plays a big role in how and where they fall.
"These shapes are really complex but the general picture is that natural hail, pointy hail, takes a very different path through a storm than smooth, ball-shaped hail," Dr Soderholm says.
Joshua Soderholm has examined more than 100 big hailstones sourced under a university program. (Upplied by University of Queensland/AAP PHOTOS)
"It falls slower. It moves through different areas of the storm. And when we run these models it falls out on the ground in different areas."
There's an enormous amount riding on accurate forecasts, given how prone coastal Australia is to highly destructive hail storms.
Scientists warned in 2023 changing atmospheric conditions were creating the ingredients for more hail-prone days and larger hailstones over Australia's most populous areas.
The research paper has been published in the Journal of the Atmospheric Sciences.
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