Weird 'ice circles' appear in Arctic sea ice, puzzling scientists

Forget crop circles, now we've got ice circles to freak out about.

Three strange, circular, amoeba-shaped ice patterns were spotted from a research plane earlier this month in Arctic sea ice, and even the top experts at NASA haven't been able to figure out what caused them.

“We saw these sorta-circular features only for a few minutes today,” mission scientist John Sonntag wrote from the field. “I don’t recall seeing this sort of thing elsewhere.”

Sonntag is a scientist with NASA's Ice Bridge mission, which is now in its 10th year of flying research missions over the Arctic and Antarctic. The holes were located about 50 miles northwest of Canada’s Mackenzie River Delta.

“I’m not sure what kind of dynamics could lead to the semi-circle shaped features surrounding the holes," IceBridge project scientist Nathan Kurtz said. "I have never seen anything like that before.”

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The holes appeared to be just a curiosity, so the Ice Bridge team put out a call to NASA and other scientists to determine the cause of the strange circles.

One expert thought seals were up to their old tricks, noting that the holes may have been gnawed out by the mammals to create an open area in the ice through which they can surface to breathe.  

"The encircling features may be due to waves of water washing out over the snow and ice when the seals surface,” said Walt Meier, a scientist at the National Snow and Ice Data Center. “Or it could be a sort of drainage feature that results from when the hole is made in the ice.”

Chris Polashenski, a sea ice scientist at the Cold Regions Research and Engineering Laboratory, said he has seen holes like this before but doesn't have a solid explanation for them. He agrees that breathing holes for seals is one possibility; equally plausible is that the holes were caused by changing temperatures within and beneath the sea ice.

Chris Shuman, a glaciologist at NASA's Goddard Space Flight Center, said "there is every chance this is just ‘warm springs’ or seeps of groundwater flowing from the mountains inland that make their presence known in this particular area.” 

For now, these Arctic ice circles can join other weird wintertime weather phenomena that include snow rollers, frozen pond circles and frost flowers.