Ed Stawinski writes from Perry Hall: "The Great Lakes give off 'lake-effect snow.' Why doesn't the Chesapeake Bay give off 'bay-effect snow?'" It can, and it has, but rarely. Ideally, lake-effect snows require cold winds across broad, open water, then rising terrain to lift and cool the air, forming snow. The bay is small, with flat terrain on the lee side. Still, north winds down the bay have dropped snow on Norfolk.