Editing Lake-effect snow (section)

=== Snow and ice cover ===
As a lake gradually freezes over, its ability to produce lake-effect precipitation decreases for two reasons. Firstly, the open ice-free liquid surface area of the lake shrinks. This reduces fetch distances. Secondly, the water temperature nears freezing, reducing overall latent heat energy available to produce squalls. To end the production of lake-effect precipitation, a complete freeze is often not necessary.<ref>{{cite web|url=http://www.comet.ucar.edu/class/smfaculty/byrd/sld022.htm |title=Lake Effect Snow: Snow/Ice Cover on the Great Lakes |first=Greg |last=Byrd |date=June 3, 1998 |website=University Corporation for Atmospheric Research |url-status=dead |archive-url=https://web.archive.org/web/20080515221206/http://www.comet.ucar.edu/class/smfaculty/byrd/sld022.htm |archive-date=2008-05-15}}</ref>

Even when precipitation is not produced, cold air passing over warmer water may produce cloud cover. Fast-moving mid-latitude cyclones, known as [[Alberta clipper]]s, often cross the Great Lakes. After the passage of a cold front, winds tend to switch to the northwest, and a frequent pattern is for a long-lasting [[low-pressure area]] to form over the [[Canadian Maritimes]], which may pull cold northwestern air across the Great Lakes for a week or more, commonly identified with the negative phase of the North Atlantic Oscillation (NAO). Since the prevailing winter winds tend to be colder than the water for much of the winter, the southeastern shores of the lakes are almost constantly overcast, leading to the use of the term "the Great Gray Funk" as a synonym for winter.{{Citation needed|date=March 2010}} These areas allegedly contain populations that suffer from high rates of [[seasonal affective disorder]], a type of psychological depression thought to be caused by lack of light.<ref>{{cite web |url=http://www.wunderground.com/health/mood.asp |title=Health Advisories: Weather and Mood |website=The Weather Underground |access-date=2007-01-04 |url-status=dead |archive-url=https://web.archive.org/web/20070221231441/http://www.wunderground.com/health/mood.asp |archive-date=2007-02-21}}</ref>{{citation needed|date=November 2017}}