是前所未有的* * * * 1973年3月。它并不是史无前例的;1979年2月仍是冠军和94.7%的冰层覆盖五大湖在最近的历史。在这之前呢?测量是间歇性和不准确的。地球观测卫星需要经常做这种测量和准确。这就是为什么记录从1973年开始。(注意:飓风的情况与此类似记录。气象学家不知道多少热带风暴和飓风从来没有达到海岸直到现代气象卫星的出现。)19世纪中期以来的温度一直在上升。 There were eight times in the 19th century when the East River froze solid enough to walk on. Since then? None. The winters of 1815-1816 and 1816-1817 are especially good bets for even greater ice coverage on the Great Lakes. 1815 was the "year without summer", thanks to the 1815 eruption of Mount Tambora. The summer of 1815 wasn't, and the winters that followed were just brutal.