For this area, the record low temp on 1/20/1985 was just outside of the top ten coldest nights in the 100-year period of record, at 11th all-time. And the record low max of 1/21 was one of the coldest 7 days ever. But as @WEATHER53 can tell you, the winds with those temps made it even more extreme. An air mass deserving of a "brutally cold" forecast.
As Ji said, the cold shot aligning with Reagan's second Inaguration made it more memorable also.