What is Lake-effect snow?
[[File:Lake Effect snow on January 10 2022.jpg|thumb|Lake Effect snow on January 10 2022]] '''Lake-effect snow''' is produced when cold air moves over a body of warmer lake water. The cold air collects the water vapor from the lake and rises, making clouds that are then carried downwind. When the vapors freeze, they start to precipitate as snow.<ref>{{Cite web|title=Lake Effect Snow|url=https://www.nesdis.noaa.gov/our-environment/ice-snow/lake-effect-snow|access-date=2024-03-01|website=National Environmental Satellite, Data, and Information Service|language=en}}</ref> Snow over areas of [[salt water]] is called '''ocean-effect''' or '''bay-effect''' snow. Sometimes, [[thundersnow]] (snow with lightning and thunder) may happen with lake-effect snow. This is because there is more instability and energy in the atmosphere. == Formation == Many things can affect lake-effect snow. They are: instability, fetch, wind shear, upstream moisture, upwind lakes, synoptic (large)-scale forcing, orography/topography, and snow or ice cover. === Instability === In order for lake-effect snow to form, there needs to be a {{convert|13|°C-change}} temperature difference between the lake and the air at about {{convert|1,500|m|ft|abbr=on|disp=or|sigfig=1}}. When there is more instability, lake effect snow can form better. === Wind shear === Directional [[Wind shear|shear]] is very important for the making of snow squalls. Weak shear usually produces more powerful snow squalls than strong shear. === Topography === Lake-effect precipitation typically increases with elevation. == Examples == === North America === ==== Great Lakes ==== In the [[Great Lakes]] region in North America, when cold air is blown from the northwest, usually by a cold front, it picks up the moisture from the lakes. The moisture forms clouds which end up dumping inches of snow on the southern and eastern shores of the Great Lakes.<ref>{{Cite web|last=US Department of Commerce|first=NOAA|title=What is a Lake Effect Snow?|url=https://www.weather.gov/safety/w