I looked up Jan '71 for here. That was a frigid AND dry month. The lack of moisture basically was the reason for not having a blockbuster month. Go figure.
Yes. Unless you have the Bering Sea to Gulf of AK trough to blowtorch the US, you'll get volatility with the propensity for very cold airmasses to enter the central US.
The 2003 event was fairly notable. Just driving up 128 when you got to the Dedham hills....must have been at least double what the lower elevations had near the Neponset and Charles River basins.