Beach strolling bird watchers on the south-eastern Swedish island of Oland were confounded recently when they stumbled upon giant ice balls the size of footballs on the shore.
Ottenby bird station’s Magnus Bladh first noticed the phenomenon as he and a colleague were walking along the beach, says a report in The Local.
“Temperatures were below freezing and there was a light wind, but it was very cold! In the seaweed we noticed at least 200 large ice balls,” said Bladh in a report to SMHI – the Swedish meteorological agency. “The balls varied in size but the biggest ones were quite large, some larger than a football,” he added. When opened, the balls revealed a soft inner core of snow surrounded by a thick layer of ice.
Bladh said he was mystified by the location of the ice balls, which lay opposed to the western winds on a bed of seaweed. SMHI reasoned that the balls were formed in the ocean as light snow blown in from the land fails to turn to ice, with the rolls of snow shaped into balls by the seawater freezing to them with the action of the waves. SMHI research showed high winds and freezing temperatures were persistent in the lead up to the discovery.
“It’s hard to say just how common ice balls are, since we are reliant on witness reports,” said Alexandra Ohlsson of the SMHI. There have only been two other such sightings recorded with the SMHI since the 1950s.