What the Heck is Frazil Ice?

First it forms. Then it multiplies. Then it attaches to underwater structures like water system intakes.It’s frazil ice, and it’s led to the frazzled nerves of managers of surface water systems, especially those along the Great Lakes. Municipalities such as Evanston, Ill., Avon Lake, Ohio, and Manitowoc and Sheboygan, Wis., are among many water utilities that have had to deal with frazil ice blocking their water intakes during cold winters.“It’s something we expect ... like most of our neighbors,” says Joe Trueblood, superintendent of the water system at Sheboygan.According to scientific sources, frazil ice forms in open, calm water, usually