The 10-year futility record at BWI was 14.3" which happened twice: 1947-48 to 1956-57 and again from 1968-69 to 1976-77. So @snowfan is correct.
However, if winter ended right now at BWI, we would have a new 10-year futility record of 12.8". In order to get above 14.3", BWI needs to score at least 15.7" this winter. So this year is essentially do-or-die.
Eta: this is 10-year average, not raw numbers.