Swirling ice disc causes a stir in Maine

A large ice disc slowly rotates in the Presumpscot River in Westbrook, Maine (Robert F Bukaty/AP)

A swirling disc of ice on a river in the US state of Maine is drawing onlookers in the heart of winter once again.

The disc has formed in the Presumpscot River in Westbrook.

A handful of dog walkers and onlookers stopped to gaze at the curious ice formation on a chilly Thursday morning around dawn.

2019 The year the ice disc first formed in the Presumpscot River in Westbrook

The disc drew fans from around the globe when it first appeared in the river in 2019.

It also partially formed in 2020.

Ice discs can form because of a current and vortex under ice.

The ice sheets spin and form into circles.

Officials in Westbrook have cautioned against attempting to go out on the ice disc.