Incredible photos: Ice on the Great Lakes at historic levelsContinue reading.
Must see: Ice caves of Lake Superior draw crowds in Wisconsin
The vast icing over of the Great Lakes has been a bane for shipping and an amazing curiosity in imagery from space. But on a smaller scale, the historic deep freeze in the Midwest this winter has produced some unique opportunities, like these seldom-seen caves on the Wisconsin coast of Lake Superior at the Apostle Islands National Lakeshore.
Cold winters are nothing new here, but this year’s temperatures have been so consistently low that park officials say they’ve made the ice formations particularly beautiful by preventing freeze-and-thaw cycles that cause blurring. Another benefit: The caves usually are accessible only by water, but Superior’s rock-solid surface is letting people walk to them for the first time since 2009. About 35,000 have made the trek.