Lake-effect snow buried northern parts of the U.S. over the Thanksgiving weekend, bringing below-freezing temperatures. Several inches of snow fell in western and northern New York, prompting a state of emergency to be declared in several counties.

Lake-effect snow occurs when cold, dry air moves over a body of water, in this case, the Great Lakes, and picks up moisture from the lake's surface. When the air moves over land, it cools, and the moisture condenses, leading to snowfall.