WESTBROOK — Has the incredible spinning disk of ice spun for the last time?

The football field-sized circle of ice rotating in the Presumpscot River was first spotted Monday and has been trumpeted internationally by the BBC, ABC’s “Good Morning America” and The New York Times, among others. But when crowds gathered along the river Wednesday to gaze at its mystery and majesty, the ice was motionless. It had lodged against the river’s edge and stopped.

“I guess if it’s stopped circulating, and it freezes into place, that might be the end of it,” said Ryan Breton, a meteorologist at Portland TV station News Center Maine (WCSH/WLBZ). “It’s going to get down to about 5 (degrees) tonight (Wednesday) and only get up to about 20 on Thursday. And we could get snow over the weekend, which will weigh it down.”

Spinning disks of varying size appear periodically during winter months in colder climates in North America and Europe, and have been the subject of speculation for years, appearing in rivers and streams but never lakes or ponds. A similar spinning disk appeared this month in rural Estonia and has been drawing curious onlookers to the shore of the Vigala River.

Breton, who researched ice disks for a TV report this week, said theories about them usually include the river current and the varying depths of the river as forces that help the ice spin and remain round.

STILL ATTRACTING A CROWD

Recently, research was conducted at the University of Liege in Belgium, where a team led by Stéphane Dorbolo showed that temperature changes in the water below a small ice disk could be the source of some of the rotational force. When the water cools to 39.2 degrees, it begins to sink and creates a vortex in the water, producing a small force that spins the ice, researchers said.

Though the disk in Westbrook had stopped moving, it was still drawing crowds Wednesday. It was still perfectly round and looked a lot like a Google Earth shot of our world from above. The public parking lot nearest the river was jammed to capacity around 12:30 p.m. and tiny Ash Street, leading to the best viewing spot, had a steady parade of cars.

On Wednesday, the disk of ice on the Presumpscot River in Westbrook was lodged against ice on the bank. With temperatures expected to be in the single digits overnight, and snow in the weekend forecast, a meteorologist suspected the disk may not survive the week.

Among the crowd of 50 to 60 people who had come to see the disk, talk turned to ways of getting it moving once again.

Vincent Rowe of Portland said he’d volunteer to go down to the riverbank, where the ice had lodged, and stomp on it to set it free. Then he reneged, for fear that he’d crack the 100-yard-wide frozen circle and spoil the magic for everyone.

Patty Fitzpatrick, also of Portland, wondered why some enterprising youngsters in a boat hadn’t tried to restore the disk’s spinning glory.

“Kids these days have no ambition,” Fitzpatrick said.

Allen Vaughan, who lives within sight of the ice disk, didn’t see it until Wednesday. His roommate called him and told him Westbrook was on the BBC news. So he decided to walk a few hundred yards from his home and see what all the fuss was about. He said he would have liked to have seen it when it was spinning, but still found its massive, perfectly round shape “fascinating.”

MAYOR SAYS IT’S GOOD FOR BUSINESS

During the days when it was slowly spinning, onlookers and people on social media compared it to a crop circle, a carousel and a “duck-go-round.” Ducks didn’t seem to mind it being motionless Wednesday, as a half-dozen were resting on it.

Pearl McNeil, left, and Patty Fitzpatrick, both of Portland, check out the rare natural phenomenon in the Presumpscot River on Wednesday. “I didn’t realize it was so huge,” said McNeil, who added that it was “bigger than it looked online.”

Westbrook’s mayor, Mike Sanphy, was on “Good Morning America” on Wednesday talking about the possible economic power of the disk.

Sanphy said later Wednesday that as people filter through downtown to see the disk, they can’t help but notice how many more shops and restaurants there are compared with a few years ago.

“We’ve been trying to revitalize the downtown, so anything that brings people in is good for business,” he said.

He had heard about a helicopter sightseeing company that had inquired with the city about bringing people on flights over the ice disk. He also said that media from Japan had called about getting a picture of it.

Pat Mahoney, a retired L.L. Bean worker from Gorham, came to see the disk after seeing a live shot of it on ABC’s “Good Morning America.” When asked if she was disappointed the disk had stopped spinning, Mahoney said, “not in the least.”

Others agreed.

“I didn’t realize it was so huge, bigger than it looked online,” said Pearl McNeil of Portland, who came to see the disk with Fitzpatrick. “It looks like the globe. We saw it on Facebook and thought we should see it. I’m glad we came.”

Ray Routhier can be contacted at 791-6454 or at:

rrouthier@pressherald.com

Twitter: RayRouthier