The Grand Sable Dunes, at the eastern end of the Lakeshore, are a perched dune formation. Sand washed ashore by wave action was then blown upslope by northerly prevailing winds until it came to rest atop a glacial moraine. The Grand Sable Dunes today form a five-mile-long sand slope that rises from Lake Superior at a 35° angle. The summits of the tallest dunes are as high as 275 feet (85 m) above lake level.
