A RARE natural phenomenon that continues to baffle scientists around the world has been spotted in a Bolton stream.

Nicola Waring noticed the series of strange, white floating discs in Bradshaw Brook while walking her cocker poo dog, Maisie, along the Kingfisher Trail, near Rigby Lane, at 7.30am on Wednesday morning, February 7.

The 51-year-old St Maxentius CE Primary School teaching assistant said: “I was sad when I first saw it, because I thought it was pollution.

“I took some photos and posted them to Facebook.”

After some tongue in cheek suggestions as to their origin – including that the discs were, perhaps, prawn crackers – it was pointed out that the phenomenon was in fact ice circles.

Varying in size, these rare natural sights are most frequently observed in North America and Scandinavia.

Though still shrouded in mystery, they’re believed to form when circular currents, or ‘eddies’ become trapped in the outer edge of a river bend.

Coupled with freezing temperatures, ice can form and the circle begin to take shape.

Ms Waring added: “I was thrilled when I found out what they were. I’ve since posted the pictures on some wildlife and nature forums online. People have been very interested to see them.”

Ice circles can grow to more than 15 metres in diameter and people have even been filmed riding larger ones around like a frosty fairground ride.

Until recently, their rotation was put down to the swirling currents in which they’re believed to form. However, very large ice circles have been seen to rotate in still water, seemingly with no force acting upon them.

This baffled scientists for decades until the mystery was unravelled by a team of scientists at the University of Liege in Belgium in 2016.

Using little more than a magnet and some popsicles, the team showed that the density of water melting from the disc caused the water to spiral beneath, pulling the disc around in a circle with it.

However, close study of ice circles’ initial formation in the wild remains illusive.

But with ice and snow forecast again for Friday, February 9, Ms Waring is hopeful spotting some more rarities on her morning walk with Maisie.