A rare collection of “ice eggs” has Ƅeen spotted in Finland, a phenoмenon experts say only occurs in highly particular conditions.

Risto Mattila, who photographed the eggs, said he and his wife were walking along Marjaniemi beach on Hailuoto island on Sunday when they came across the icy balls covering a 30-metre (98ft) expanse of shoreline.“The biggest of the eggs was about the size of a football,” said Mattila, an amateur photographer. “It was an amazing view.

Jouni Vainio, an ice specialist at the Finnish Meteorological Institute, expressed astonishment at witnessing a phenomenon he had never seen before. He stated that while this occurrence was not common, it could potentially happen approximately once a year under specific weather conditions.

According to Vainio, several factors contribute to this phenomenon, including the requirement of the right air temperature (slightly below zero), the water temperature being close to freezing point, a sandy beach with a gentle slope, and calm waves or perhaps a light swell.

Additionally, a crucial element for this phenomenon is the presence of something that acts as the core. The core serves as a focal point for ice accumulation, and as the swell moves it back and forth along the beach, it collects more ice. As this small ball-like surface gets wet, it freezes and gradually grows larger and larger.

Dr. James Carter, an emeritus professor of geography-geology at Illinois State University, suggests that autumn is the ideal season to witness this phenomenon. During autumn, as temperatures drop, ice begins to form on the surface of the water. When the ice is moved by waves, it takes the form of slush, contributing to the unique occurrence.