This December, which thickly blanketed much of Wisconsin, left Duluth with no more than 19.2 inches of snow, the equivalent of less than an inch of water. That relatively skimpy precipitation pattern, which has dominated in the last few years, has brought Lake Superior to its lowest point in 75 years. It was just a scant 4 inches above the lake's record low, measured in 1925. When Lake Superior is this low, hydrologist Frank Quinn explained, an absolute minimum of water is released through gates in the St. Marys River into Lakes Michigan and Huron, which are considered a single body of water. Mich. Relief, however, is in sight, along the shoreline draped with snow and ice.
Ice cover prevents further evaporation from the lake surface.
Winter snowpack and spring melt-off are the forces driving most of the annual spring rise in water levels, he said. But where the pack accumulates and when it melts are more important still. Nevertheless, Quinn said, some snow is better than none. But if it trickles, a little at a time, we're not going to get a significant increase in lake levels. The 10-day outlook for the Midwest from the National Weather Service indicates that the second possibility might be more likely.