The Westbrook ice disc has returned three years after it made its first appearance. Credit: Courtesy of CBS 13

WESTBROOK – Three years after it made its first appearance, the famous ice disc is once again reforming in Westbrook.

The disc — located in the Presumpscot River — is pretty large already, but the ice is still very thin.

The discs “occur at bends in the river where the accelerating water creates a force called ‘rotational shear,’ which breaks off a chunk of ice and twists it around,” the Daily Mail once reported, when one of the circles was seen in Great Britain for what was believed to be the first time in 2009. “As the disc rotates, it grinds against surrounding ice, smoothing into a perfect circle.”

In 2019, city officials said it formed by the churning water current created by the waterfall just 100 feet north of the disc.

The largest naturally occurring ice disc otherwise reported was about 54 yards in diameter, forming in Pite River in Sweden in 1987, although there’s no obvious central authority on ice discs worldwide.

The Westbrook ice disc is not the first reported one in Maine. Smaller ones were discovered in the Millinocket area in January of 2019 and in the Hampden area last February. Meanwhile, a giant one formed in Milo in December of 2019, but it quickly disintegrated.

BDN reporter Rosemary Lausier contributed to this report.