The Great Blizzard of 1978

January 26, 1978:

Late on January 24 the surface maps revealed a moisture laden Gulf Low developing over the southern United States while a separate, and unrelated low pressure system was present over the Upper Midwest. In about 24 hours, the merger of the subtropical (containing a wind max of 130 knots) and polar (containing a wind max of 110 knots) jet streams would lead to an unusual convergence of these two low pressures over the Ohio Valley, known as "phasing". Such a phenomenon usually leads to explosive development of the surface low and the Great Blizzard was no exception. The low over Gulf States underwent bombogenesis as it moved rapidly northward during the evening of January 25 (record low pressures were logged across parts of the South and Mid-Atlantic). Bombogenesis events require a storm's central pressure to drop more than 24 millibars in 24 hours; the Great Blizzard deepened by a remarkable 40 millibars in that span of time.
As the storm headed for Ohio, this resulted in a "storm of unprecedented magnitude", according to the National Weather Service, which categorized it as a rare severe blizzard, the most severe grade of winter storm. Particularly hard hit were the states of Illinois, Indiana, Kentucky, Michigan, Ohio, and southeast Wisconsin where up to 40 inches (102 cm) of snow fell. Winds gusting up to 100 miles per hour (161 km/h) caused drifts that nearly buried some homes. Wind chill values reached −60 °F (−51 °C) across much of Ohio where 51 of the total 70 storm-related deaths occurred.  The second lowest atmospheric pressure ever recorded in the United States, apart from a tropical system, occurred as the storm passed over Cleveland, Ohio. The barometer fell to 28.28 inches of mercury (958 mbar) on the morning of January 26. Nearby Detroit, Michigan fell to 28.34 inches of mercury (960 mbar).
The absolute low pressure with this storm was picked up at Sarnia, Ontario at around the same time, where the barometer bottomed out at 28.21 inches of mercury (955 mbar). Toronto fell to 28.40 inches, breaking the old record by 0.17. Canada did not escape the wrath of the storm as blizzard conditions were common across southwestern Ontario. London was paralyzed by 41 centimetres (16 in) of snow and winds gusting to 128 kilometres per hour (80 mph). The storm initially began out as rain but quickly changed over to heavy snow during the pre-dawn hours (as arctic air deepened ahead of the storm) leading to frequent whiteouts and zero visibility during the day on Thursday, January 26.
The Blizzard was the worst in Ohio history where 51 people died as a result of the storm. Over 50,000 members of the Ohio National Guard were called in to make numerous rescues. Police asked citizens who had four-wheel drive vehicles and snowmobiles to transport doctors to the hospital. From January 26 to 27, the entire Ohio Turnpike was shut down for the first time ever.^[5] The total effect on transportation in Ohio was described by Major General James C. Clem of the Ohio National Guard as comparable to a nuclear attack

This is before my memory can reach, but it is the stuff of legend around here.  The photographs from that time might not be impressive in the Dakotas, but they are for Ohio.  I've been told it was almost 70 degrees and rained like crazy before the temperature plummeted.