The frequency and intensity of early winter (November) coldwaves were investigated for the north central United States. Twenty-two such storms occurred from 1901 to 1985, and were most frequent in the 1950s and early 1960s, and again from the mid 1970s to the present.

November coldwaves are most often the result of Colorado cyclones moving to the east northeast. On average, temperature declines of 22°C or more within 24 hours, falling to at least 0°C, impacted about 40 percent of the 12-state region. The storms were most often accompanied by strong winds, wind chill, heavy snow to the west, and thunderstorms to the east, i.e., the trappings of a severe winter storm. Many of these storms inflicted severe damage on land and on the Great Lakes, sometimes taking lives of those not anticipating such a severe “winter” storm in November.

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