A giant disk of ice started to spin in the Presumpscot River 15 miles west of Portland, Maine, early last week. It is not entirely clear when the frozen, football-field-size skating rink formed, but once it was on the move, it drew a crowd. It slowed briefly last Wednesday, thwarted by the friction of the apparently frozen water surrounding it, but according to the Boston Globe, an unnamed hero from Freeport, Maine, quickly liberated the most-watched hunk of ice in the country, if not the world.
A week later, after a multiday outbreak of bitter Arctic air, the Presumpscot lazy Susan has stopped rotating again, and it is not clear whether or when it will restart. A blanket of snow — unclear how thick ― covers the disk. Assuming nothing damages the disk between now and when the river ice begins to melt, it could live to spin again.
The circle of ice, 290 feet in diameter, spun up at a bend in the river. The unusual phenomenon attracted far-reaching attention and sparked some Internet delight. It is not even the only ice disk in Maine. Another one — only about 40 feet wide — is spinning in Baxter State Park, 200 miles north of Portland.
Ice disks are not uncommon, but they only happen in certain locations. If one side of the river is flowing faster than the other, the ice on top experiences a shearing force, analogous to forcing a vinyl record to spin by flicking one side. When the ice spins, its edges are shaved off where it grinds against other ice or obstacles. Eventually, a perfectly-trimmed circle is all that is left.
Temperatures are warming up in Maine this week, and rain is in the forecast. Wednesday’s high should reach 38 and will soar to the upper 40s on Thursday as heavy rain moves in. That will almost certainly erode or melt the ice disk at least partly. The rain will make things worse, eating away the ice disk from the top, rather than just on the edges.
The fate of Maine’s most popular Internet attraction is uncertain, but you can watch it erode on a live webcam hosted by the city of Westbrook and Brown University.