Twenty fours hours before all chaos would break loose, National Weather Center meteorologists forecast “a chance of snow” for Thursday, Jan. 26, 1967. Had they known then what they know now, they might have called for “a big chance of snow” or “a chance of big snow.” As in many recent years, the winter leading up to the Blizzard of ’67 had been a mild one, said Mark Ratzer, senior forecaster for the National Weather Service’s Romeoville office. “We were in the 50s on Jan. 21 and 22.” Two days before the snowstorm hit, Chicago’s high temperature was 65 degrees...