The formations, called ice heaves, often happen in the spring along the shorelines as ice begins to melts and wind pushes it up into solid, jagged waves. But they can also be seen where water levels and temperatures fluctuate, said Hilary Dugan, professor with UW-Madison’s Limnology Department. As water freezes it expands, with sections pushing against one another to create pressure ridges between a few inches to a few feet high, Dugan said.
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