Spring break-up, March 26, 2009

After one of the area’s colder and snowier winters in some time, open water is again visible this week from the eighth floor of the Cofrin Library at UW-Green Bay. Also visible are several sizeable “icebergs” or, more accurately, “ice shoves.”

The formations occur periodically but relatively infrequently on the lower bay near campus. They form when incoming tributaries (in this case, the Fox River) erode the bay’s icepack around the edges. With open water on the windward side, high winds can cause the sheets of ice (a foot thick or more) to crack up and stack up along shorelines and shallow shoals. Following some spring storms, the ridges of deposited ice have reached 20 feet in height, damaging shoreline property. UW-Green Bay Prof. Steve Dutch shares photos of one such spring break-up, about 15 miles north of campus where the bay widens out, on his website; click here.