Some of those are because of measuring technique also. People tend to forget that. How much is debatable but noteworthy. Will is correct though, with normal measuring, it's pretty tough to get 30" of snow on the nose. The Northshore since 1870 has seen a few since then as Will stated. A recap: 1898 (February (Lawrence, MA/ Northshore)),1969 (February),1978 (February), 2003 (December), 2005 (January). They are pretty rare/hard to come by. That's why they are usually deemed "Historic" in nature when they do occur.