Cold air is sweeping across the Great Lakes region, bringing lake-effect snow from Michigan's Upper Peninsula to Western New York. Snowfall started Wednesday in Houghton, Michigan, and is expected to continue through Thanksgiving. The National Weather Service has issued a blizzard warning for the Keweenaw Peninsula. Forecasters say that cold air, often from Canada, blows over the Great Lakes, creating conditions for heavy snowfall. Areas like Buffalo, New York, are particularly affected, with significant snow expected. Lake-effect storms previously dumped over six feet of snow in Western New York in November 2022.