
THE sun glints off this rare display of “ice eggs” spread along 30 metres of Finland’s Marjaniemi beach on Hailuoto Island.
Amateur photographer Risto Mattila stumbled upon the sight during a stroll and told journalists it was unlike anything he had ever seen. Luckily, he had his camera to hand. The ice balls range from the size of an egg to a football. People flocked to the area, hoping to catch a glimpse before they melted.
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Waves are key to the ice structures forming, says Walt Meier at the National Snow and Ice Data Center in Colorado. You need enough motion to prevent the ice from freezing into a sheet, but not enough that it prevents any ice forming.
Once the ice balls start to form, water washes over them and freezes, increasing their size and smoothing the surface, he says. The ice balls then wash ashore.