The Great Blue Norther of November 11, 1911 was a cold snap that affected the central United States on Saturday, November 11, 1911. Many cities broke record highs, going into the 70s and 80s early that afternoon. By nightfall, cities were dealing with temperatures in the teens and single-digits on the Fahrenheit scale. This is the only day in many midwest cities' weather bureau jurisdictions where the record highs and lows were broken for the same day. Some cities experienced tornadoes on Saturday and a blizzard on Sunday. A blizzard even occurred within one hour after an F4 tornado hit Rock County, Wisconsin.