Great Blizzard of 1978
| Category 5 "Extreme" (RSI: 25.84) | |
Surface map on the morning of January 26, 1978.
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| Type |
Extratropical cyclone Nor'easter Blizzard Winter storm |
|---|---|
| Formed | January 24, 1978 |
| Dissipated | January 29, 1978 |
| Lowest pressure | 955.5 mb (28.22 inHg) |
| Maximum snowfall or ice accretion | 36 in (91 cm) South Bend, Indiana |
| Damage | Unknown |
| Casualties | At least 71 fatalities |
| Areas affected | Central United States, Eastern United States, Eastern Canada |
The Great Blizzard of 1978, also known as the White Hurricane, was a historic winter storm that struck the Ohio Valley and Great Lakes regions from Wednesday, January 25 through Friday, January 27, 1978. The 956.0 mb (28.23 inHg) barometric pressure measurement recorded in Mount Clemens, Michigan was the third lowest non-tropical atmospheric pressure recorded in the mainland United States and the lowest in the Central United States. The lowest confirmed pressure for a non-tropical system in the continental United States was set by a January 1913 Atlantic coast storm. The lowest central pressure for the 1978 blizzard was 955.5 mb (28.22 inHg) measured in Sarnia, Ontario, Canada. On rare occasions, extra-tropical cyclones with central pressures below 28 inches of mercury or about 95 kPa (950 mb) have been recorded in Wiscasset, Maine (27.9") and Newfoundland (27.76").
Late on January 24, 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 jet stream (containing a wind max of 130 knots) and polar jet stream (containing a wind max of 110 knots) would lead the low-pressure system to undergo explosive cyclogenesis as it moved rapidly northward during the evening of January 25 (record low pressures were logged across parts of the South and Mid-Atlantic). To be classified as undergoing explosive cyclogenesis, a storm's central pressure must drop at least 24 millibars, or an average of 1 millibar per hour, over a 24-hour period; the Great Blizzard deepened by a remarkable 40 millibars in that span of time.
The storm initially began 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. 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 third lowest atmospheric pressure ever recorded in the United States, apart from a tropical system, occurred as the storm passed over Mount Clemens, Michigan. The barometer fell to 956.0 mb (28.23 inHg) on January 26. Nearby Detroit, Michigan fell to 28.34 inches of mercury (960 mbar).
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Wikipedia