It's a very rare sight, but given specific environmental factors, including the temperature of the air and water and the pattern of movement in the water, frozen waves can be spotted in the winter. This footage shows the beautiful phenomenon off the coast of Dennis, Massachusetts, in late January.
This harsh winter, photos of the "slurpee waves" crashing near Nantucket beaches taken by by Jonathan Nimerfroh quickly went viral. Nimerfroh told NBC, "When I pulled up to the beach, I could see the horizon just look strange. When I got to the top off the dunes I saw that beginning about 300 yards away from the shoreline the ocean was starting to freeze."
So, how does this phenomenon occur? Oceanographer told Carin Ashjian told Smithsonian Magazine, "Salt water freezes at 28.8 °F (-1.4 °C), and when the air is colder than that, breaking waves can deposit layer upon thin layer of ice onto the ground, which add up to form a solid rind." The conditions in Nantucket were just perfect for the icy sight.
YouTube user chriseth16 captured the unbelievable waves on video.