Hailstones the size of your hand could soon help us predict massive storms fun facts

Hailstones that are bigger than your fist plummeting towards the ground pose huge risks to people caught outside during storms.

Now, new analysis of these giant ’ inner structure reveals how they are able to get so big – a discovery which could help scientists predict hailstorms before they become a threat.

Hailstones are formed during storms, when a raindrop freezes in a very cold part of a cloud. They then grow in diameter as gravity pulls the increasingly heavy particles downwards, where they can eventually drop to Earth.

For the new study, published in Frontiers in Environmental Scienceresearchers in Catalonia (an autonomous region in northern Spain) collected giant hailstones up to 12cm (4.7in) in diameter – as tall as a soda can.

They then used CT scans to look inside three of the. You may have heard of these scans in more of a medical context – usually, the rotating X-ray machine creates 3D images of human bodies.

But in this case, the machines – borrowed from a dental clinic – allowed the team to study the ‘anatomy’ of the giant ice balls without breaking them up.

“We wanted to use a technique that would provide more information regarding the internal layers of the , but without breaking the samples

,” said senior author Professor Xavier Úbeda of the University of Barcelona. “We didn’t expect to obtain as clear imagery as we got.”

Úbeda and his team obtained 512 images of the hailstones’ internal structure, known as ‘slices’. These slices reveal each layer’s density, showing how the hailstone grew at different stages of the hailstorm.

The team discovered that even the most spherical hailstones have irregular insides – none of the stones’ cores were in their centres. Bizarrely,

this was particularly the case for the near-perfect-looking spheres, whose cores were most off-centre.

The researchers say this reveals thatdo not grow evenly in each direction, contrary to previous assumptions about hailstones.

The used in this study were collected, vacuum-packed and preserved after a violent thunderstorm that hit Spain in summer 2022.

That same summer, Spain was hit by severe drought, but it’s likely that the hot conditions made tropical storms stronger.

The researchers say their new findings could help with predicting similar storms in the future by forecasting hail formation – and therefore helping to limit the amount of damage they cause.