Lake-effect Snow
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Lake-effect snow is produced during cooler atmospheric conditions when a cold
air mass In meteorology, an air mass is a volume of air defined by its temperature and humidity. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to l ...
moves across long expanses of warmer
lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
water. The lower layer of air, heated up by the lake water, picks up
water vapor (99.9839 °C) , - , Boiling point , , - , specific gas constant , 461.5 J/( kg·K) , - , Heat of vaporization , 2.27 MJ/kg , - , Heat capacity , 1.864 kJ/(kg·K) Water vapor, water vapour or aqueous vapor is the gaseous p ...
from the lake and rises up through the colder air above. The vapor then freezes and is deposited on the leeward (downwind) shores. The same effect also occurs over bodies of saline water, when it is termed ocean-effect or bay-effect snow. The effect is enhanced when the moving air mass is uplifted by the orographic influence of higher elevations on the downwind shores. This uplifting can produce narrow but very intense bands of
precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
, which deposit at a rate of many inches of snow each hour, often resulting in a large amount of total snowfall. The areas affected by lake-effect snow are called
snowbelt The Snowbelt is the region near the Great Lakes in North America where heavy snowfall in the form of lake-effect snow is particularly common. Snowbelts are typically found downwind of the lakes, principally off the eastern and southern shores. Ca ...
s. These include areas east of the
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lak ...
in North America, the west coasts of northern Japan, the
Kamchatka Peninsula The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and w ...
in Russia, and areas near the Great Salt Lake,
Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Rom ...
,
Caspian Sea The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia ...
,
Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and ...
,
Adriatic Sea The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to t ...
, and
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...
. Lake-effect blizzards are the
blizzard A blizzard is a severe snowstorm characterized by strong sustained winds and low visibility, lasting for a prolonged period of time—typically at least three or four hours. A ground blizzard is a weather condition where snow is not falling ...
-like conditions resulting from lake-effect snow. Under certain conditions, strong winds can accompany lake-effect snows creating blizzard-like conditions; however, the duration of the event is often slightly less than that required for a blizzard warning in both the US and Canada. If the air temperature is low enough to keep the precipitation frozen, it falls as lake-effect snow. If not, then it falls as lake-effect rain. For lake-effect rain or snow to form, the air moving across the lake must be significantly cooler than the surface air (which is likely to be near the temperature of the water surface). Specifically, the air temperature at an altitude where the
air pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars ...
is (roughly vertically) should be lower than the temperature of the air at the surface. Lake-effect occurring when the air at is much colder than the water surface can produce
thundersnow Thundersnow, also known as a winter thunderstorm or a thundersnowstorm, is a kind of thunderstorm with snow falling as the primary precipitation instead of rain. It is considered a rare and unusual phenomenon. It typically falls in regions of s ...
, snow showers accompanied by
lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...
and
thunder Thunder is the sound caused by lightning. Depending upon the distance from and nature of the lightning, it can range from a long, low rumble to a sudden, loud crack. The sudden increase in temperature and hence pressure caused by the lightning pr ...
(caused by larger amounts of energy available from the increased instability).


Formation

Some key elements are required to form lake-effect precipitation and which determine its characteristics: instability, fetch, wind shear, upstream moisture, upwind lakes, synoptic (large)-scale forcing, orography/topography, and snow or ice cover.


Instability

A temperature difference of (or as past researchers have estimated: between 15 and 25 °C) between the lake temperature and the height in the atmosphere (about at which barometric pressure measures ) provides for absolute instability and allows vigorous heat and moisture transportation vertically. Atmospheric lapse rate and convective depth are directly affected by both the mesoscale lake environment and the synoptic environment; a deeper convective depth with increasingly steep lapse rates and a suitable moisture level allow for thicker, taller lake-effect precipitation clouds and naturally a much greater precipitation rate.


Fetch

The distance that an air mass travels over a body of water is called fetch. Because most lakes are irregular in shape, different angular degrees of travel yield different distances; typically, a fetch of at least is required to produce lake-effect precipitation. Generally, the larger the fetch, the more precipitation produced. Larger fetches provide the boundary layer with more time to become saturated with water vapor and for heat energy to move from the water to the air. As the air mass reaches the other side of the lake, the engine of rising and cooling water vapor pans itself out in the form of condensation and falls as snow, usually within of the lake, but sometimes up to about .


Wind shear

Directional
shear Shear may refer to: Textile production *Animal shearing, the collection of wool from various species **Sheep shearing *The removal of nap during wool cloth production Science and technology Engineering *Shear strength (soil), the shear strength ...
is one of the most important factors governing the development of squalls; environments with weak directional shear typically produce more intense squalls than those with higher shear levels. If directional shear between the surface and the height in the atmosphere at which the barometric pressure measures is greater than 60°, nothing more than flurries can be expected. If the directional shear between the body of water and the vertical height at which the pressure measures is between 30° and 60°, weak lake-effect bands are possible. In environments where the shear is less than 30°, strong, well organized bands can be expected. Speed shear is less critical but should be relatively uniform. The wind-speed difference between the surface and vertical height at which the pressure reads should be no greater than so as to prevent the upper portions of the band from shearing off. However, assuming the surface to winds are uniform, a faster overall velocity works to transport moisture more quickly from the water, and the band then travels much farther inland.


Upstream moisture

A lower upstream relative humidity lake effect makes condensation, clouds, and precipitation more difficult to form. The opposite is true if the upstream moisture has a high relative humidity, allowing lake-effect condensation, cloud, and precipitation to form more readily and in a greater quantity.


Upwind lakes

Any large body of water upwind impacts lake-effect precipitation to the lee of a downwind lake by adding moisture or pre-existing lake-effect bands, which can reintensify over the downwind lake. Upwind lakes do not always lead to an increase of precipitation downwind.


Synoptic forcing

Vorticity advection aloft and large upscale ascent help increase mixing and the convective depth, while cold air advection lowers the temperature and increases instability.


Orography and topography

Typically, lake-effect precipitation increases with elevation to the lee of the lake as topographic forcing squeezes out precipitation and dries out the squall much faster.


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. 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 An Alberta clipper, also known as an Alberta low, Alberta cyclone, Alberta lee cyclone, Canadian clipper, or simply clipper, is a fast-moving low-pressure system that originates in or near the Canadian province of Alberta just east of the Rock ...
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 In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...
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. These areas allegedly contain populations that suffer from high rates of
seasonal affective disorder Seasonal affective disorder (SAD) is a mood disorder subset, in which people who have normal mental health throughout most of the year exhibit depressive symptoms at the same time each year. Common symptoms include sleeping too much, having li ...
, a type of psychological depression thought to be caused by lack of light.


Great Lakes region


United States

Cold winds in the winter typically prevail from the northwest in the Great Lakes region, producing the most dramatic lake-effect snowfalls on the southern and eastern shores of the
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lak ...
. This lake effect results in much greater snowfall amounts on the southern and eastern shores compared to the northern and western shores of the Great Lakes. The most affected areas include the
Upper Peninsula of Michigan The Upper Peninsula of Michigan – also known as Upper Michigan or colloquially the U.P. – is the northern and more elevated of the two major landmasses that make up the U.S. state of Michigan; it is separated from the Lower Peninsula by ...
;
Central New York Central New York is the central region of New York State, including the following counties and cities: With a population of about 773,606 (2009) and an area of , the region includes the Syracuse metropolitan area. Definitions The New York ...
;
Western New York Western New York (WNY) is the westernmost region of the U.S. state of New York. The eastern boundary of the region is not consistently defined by state agencies or those who call themselves "Western New Yorkers". Almost all sources agree WNY i ...
;
Northwestern Pennsylvania Western Pennsylvania is a region in the U.S. state of Pennsylvania, covering the western third of the state. Pittsburgh is the region's principal city, with a metropolitan area population of about 2.4 million people, and serves as its economic ...
; Northeastern Ohio; southwestern Ontario and central Ontario; Northeastern Illinois (along the shoreline of Lake Michigan); northwestern and north central
Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...
(mostly between Gary and Elkhart); northern
Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...
(near Lake Superior); and
West Michigan West Michigan and Western Michigan are terms for an arbitrary region in the U.S. state of Michigan's Lower Peninsula. Most narrowly it refers to the Grand Rapids- Muskegon-Holland area, and more broadly to most of the region along the Lower Pe ...
.
Tug Hill Tug Hill, sometimes referred to as the Tug Hill Plateau, is an upland region in northern New York State, famous for heavy winter snows. The Tug Hill region is east of Lake Ontario, north of Oneida Lake, and west of the Adirondack Mountains. The r ...
in New York's North Country region has the second-most snow amounts of any nonmountainous location within the continental U.S., trailing only the Upper Peninsula, which can average over of snow per year. Lake-effect snows on the Tug Hill plateau (east of
Lake Ontario Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York. The Canada–United States border ...
) can frequently set daily records for snowfall in the United States. Tug Hill receives, typically, over of snow each winter. In February 2007, a prolonged lake-effect snow event left of snow on the Tug Hill Plateau. Syracuse, New York, directly south of the Tug Hill Plateau, receives significant lake-effect snow from Lake Ontario, and averages of snow per year, which is enough snowfall to be considered one of the "snowiest" large cities in America. A small amount of lake-effect snow from the
Finger Lakes The Finger Lakes are a group of eleven long, narrow, roughly north–south lakes located south of Lake Ontario in an area called the ''Finger Lakes region'' in New York, in the United States. This region straddles the northern and transitional ...
falls in upstate New York, as well. If the wind blows almost the entire length of either
Cayuga Lake Cayuga Lake (,,) is the longest of central New York's glacial Finger Lakes, and is the second largest in surface area (marginally smaller than Seneca Lake) and second largest in volume. It is just under long. Its average width is , and it is ...
or Seneca Lake,
Ithaca Ithaca most commonly refers to: *Homer's Ithaca, an island featured in Homer's ''Odyssey'' *Ithaca (island), an island in Greece, possibly Homer's Ithaca *Ithaca, New York, a city, and home of Cornell University and Ithaca College Ithaca, Ithaka ...
or Watkins Glen, respectively, can have a small lake-effect snowstorm.
Lake Erie Lake Erie ( "eerie") is the fourth largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also h ...
produces a similar effect for a zone stretching from the eastern suburbs of
Cleveland Cleveland ( ), officially the City of Cleveland, is a city in the U.S. state of Ohio and the county seat of Cuyahoga County. Located in the northeastern part of the state, it is situated along the southern shore of Lake Erie, across the U.S. ...
through
Erie Erie (; ) is a city on the south shore of Lake Erie and the county seat of Erie County, Pennsylvania, United States. Erie is the fifth largest city in Pennsylvania and the largest city in Northwestern Pennsylvania with a population of 94,831 a ...
to Buffalo. Remnants of lake-effect snows from Lake Erie have been observed to reach as far south as Garrett County, Maryland, and as far east as
Geneva, New York Geneva is a city in Ontario and Seneca counties in the U.S. state of New York. It is at the northern end of Seneca Lake; all land portions of the city are within Ontario County; the water portions are in Seneca County. The population was 13, ...
. Because it is not as deep as the other lakes, Erie warms rapidly in the spring and summer, and is frequently the only Great Lake to freeze over in winter. Once frozen, the resulting ice cover alleviates lake-effect snow downwind of the lake. Based on stable isotope evidence from lake sediment coupled with historical records of increasing lake-effect snow, global warming has been predicted to result in a further increase in lake-effect snow. A very large
snowbelt The Snowbelt is the region near the Great Lakes in North America where heavy snowfall in the form of lake-effect snow is particularly common. Snowbelts are typically found downwind of the lakes, principally off the eastern and southern shores. Ca ...
in the United States exists on the
Upper Peninsula of Michigan The Upper Peninsula of Michigan – also known as Upper Michigan or colloquially the U.P. – is the northern and more elevated of the two major landmasses that make up the U.S. state of Michigan; it is separated from the Lower Peninsula by ...
, near the cities of
Houghton Houghton may refer to: Places Australia * Houghton, South Australia, a town near Adelaide * Houghton Highway, the longest bridge in Australia, between Redcliffe and Brisbane in Queensland * Houghton Island (Queensland) Canada *Houghton Township, ...
, Marquette, and
Munising Munising ( ') is a city in Alger County in the U.S. state of Michigan. The population was 2,355 at the 2010 census. It is the county seat of Alger County. The city is partially surrounded by Munising Township, but the two are administered auton ...
. These areas typically receive of snow each season. For comparison, on the western shore,
Duluth, Minnesota , settlement_type = City , nicknames = Twin Ports (with Superior), Zenith City , motto = , image_skyline = , image_caption = Clockwise from top: urban Duluth skyline; Minnesota ...
receives per season.
Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...
and Lake Huron rarely freeze because of their size and depth; hence, lake-effect snow can fall continually in the Upper Peninsula and Canadian snowbelts during the winter. Main areas of the Upper Peninsula snow belt include the Keweenaw Peninsula and Baraga, Marquette and Alger Counties, where Lake Superior contributes to lake-effect snow, making them a prominent part of the Midwestern snow belt. Records of of snow or more have been set in many communities in this area. The Keweenaw Peninsula averages more snowfall than almost anywhere in the United States—more than anywhere east of the
Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it fl ...
and most of all nonmountainous regions of the continental United States. Because of the howling storms across Lake Superior, which cause dramatic amounts of precipitation, the lake-effect snow is said to make the Keweenaw Peninsula the snowiest place east of the
Rockies The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
. Only one official weather station exists in this region. Located in
Hancock, Michigan Hancock is a city in Houghton County in the U.S. state of Michigan. It is across the Keweenaw Waterway from the city of Houghton on the Keweenaw Peninsula. The population was 4,634 at the 2010 census. The Weather Channel has consistently rank ...
; this station averages well over per year. Farther north in the peninsula, lake-effect snow can occur with any wind direction. The road commission in
Keweenaw County, Michigan Keweenaw County (, ; , ) is a county in the Upper Peninsula of the U.S. state of Michigan, the state's northernmost county. As of the 2020 United States Census, the population was 2,046, making it Michigan's least populous county. It is also the ...
, collects unofficial data in a community called Delaware, and it strictly follows the guidelines set forth by the National Weather Service. This station averages over per season. Even farther north, a ski resort called
Mount Bohemia Mount Bohemia is the 5th highest point in the Keweenaw Peninsula and the 52nd highest prominent peak in Michigan with an elevation of . Mount Bohemia is host to a ski resort bearing the same name located at the northernmost portion of the Keweena ...
receives an unofficial annual average of . Herman, Michigan, averages of snow every year. Lake-effect snow can cause blinding whiteouts in just minutes, and some storms can last days.
Western Michigan West Michigan and Western Michigan are terms for an arbitrary region in the U.S. state of Michigan's Lower Peninsula. Most narrowly it refers to the Grand Rapids- Muskegon-Holland area, and more broadly to most of the region along the Lower Pen ...
, western Northern Lower Michigan, and
Northern Indiana Northern Indiana is a region of the U.S. State of Indiana, including 26 counties which border the states of Illinois, Michigan, and Ohio. Northern Indiana is also considered part of the Great Lakes Megalopolis. The area is generally classified i ...
can get heavy lake-effect snows as winds pass over Lake Michigan and deposit snows over
Muskegon Muskegon ( ') is a city in Michigan. It is the county seat of Muskegon County. Muskegon is known for fishing, sailing regattas, pleasure boating, and as a commercial and cruise ship port. It is a popular vacation destination because of the expans ...
,
Traverse City Traverse City ( ) is a city in the U.S. state of Michigan. It is the county seat of Grand Traverse County, although a small portion extends into Leelanau County. It is the largest city in the 21-county Northern Michigan region. The population was ...
, Grand Rapids,
Kalamazoo Kalamazoo ( ) is a city in the southwest region of the U.S. state of Michigan. It is the county seat of Kalamazoo County. At the 2010 census, Kalamazoo had a population of 74,262. Kalamazoo is the major city of the Kalamazoo-Portage Metropoli ...
, New Carlisle,
South Bend South Bend is a city in and the county seat of St. Joseph County, Indiana, on the St. Joseph River near its southernmost bend, from which it derives its name. As of the 2020 census, the city had a total of 103,453 residents and is the fourt ...
, and Elkhart, but these snows abate significantly before
Lansing Lansing () is the capital of the U.S. state of Michigan. It is mostly in Ingham County, although portions of the city extend west into Eaton County and north into Clinton County. The 2020 census placed the city's population at 112,644, makin ...
or
Fort Wayne, Indiana Fort Wayne is a city in and the county seat of Allen County, Indiana, United States. Located in northeastern Indiana, the city is west of the Ohio border and south of the Michigan border. The city's population was 263,886 as of the 2020 Censu ...
. When winds become northerly or aligned between 330 and 390°, a single band of lake-effect snow may form, which extends down the length of Lake Michigan. This long fetch often produces a very intense, yet localized, area of heavy snowfall, affecting cities such as Laporte and Gary. Lake-effect snow is uncommon in Detroit, Toledo,
Milwaukee Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee ...
, and Chicago, because the region's dominant winds are from the northwest, making them upwind from their respective Great Lakes, although they, too, can see lake-effect snow during easterly or northeasterly winds. More frequently, the north side of a low-pressure system picks up more moisture over the lake as it travels east, creating a phenomenon called lake-enhanced precipitation. File:Buffalo2001-20.jpg,
Buffalo, New York Buffalo is the second-largest city in the U.S. state of New York (behind only New York City) and the seat of Erie County. It is at the eastern end of Lake Erie, at the head of the Niagara River, and is across the Canadian border from Sou ...
, after of snow fell from December 24, 2001, to December 28, 2001 File:Fultonles.jpg, Fulton, New York, after a snowburst dropped of snow over most of Oswego County January 28–31, 2004 File:Snow-removal-cleveland-4.jpg, The Veteran's Day storm of November 9–14, 1996, may be the most severe early-season lake-effect snow storm the Great Lakes has witnessed in the past 50 years. At the height of the storm, over 160,000 customers were without power in Greater Cleveland alone, as the storm produced isolated snowfall tallies approaching .


Ontario, Canada

Because Southwestern Ontario is surrounded by water on three sides, many parts of Southwestern and Central Ontario get a large part of their winter snow from lake-effect snow. This region is notorious for the whiteouts that can suddenly reduce highway visibility on North America’s busiest highway ( Ontario Highway 401) from clear to zero. The region most commonly affected spans from
Port Stanley Stanley (; also known as Port Stanley) is the capital city of the Falkland Islands. It is located on the island of East Falkland, on a north-facing slope in one of the wettest parts of the islands. At the 2016 census, the city had a popula ...
in the west, the
Bruce Peninsula The Bruce Peninsula is a peninsula in Ontario, Canada, that divides Georgian Bay of Lake Huron from the lake's main basin. The peninsula extends roughly northwestwards from the rest of Southwestern Ontario, pointing towards Manitoulin Island, ...
in the north, Niagara-on-the-Lake to the east, and
Fort Erie Fort Erie is a town on the Niagara River in the Niagara Region, Ontario, Canada. It is directly across the river from Buffalo, New York, and is the site of Old Fort Erie which played a prominent role in the War of 1812. Fort Erie is one of Ni ...
to the south. The heaviest accumulations usually happen in the Bruce Peninsula, which is between Lake Huron and Georgian Bay. So long as the Great Lakes are not frozen over, the only time the Bruce Peninsula does not get lake-effect snow is when the wind is directly from the south. Toronto and
Hamilton Hamilton may refer to: People * Hamilton (name), a common British surname and occasional given name, usually of Scottish origin, including a list of persons with the surname ** The Duke of Hamilton, the premier peer of Scotland ** Lord Hamilt ...
are usually spared lake-effect squalls because they are not on the leeward side of Lake Ontario during the dominant northwest winds. Some central and northern portions of the Greater Toronto Area, though, can be affected a few times each year by lake-effect snow from
Georgian Bay Georgian Bay (french: Baie Georgienne) is a large bay of Lake Huron, in the Laurentia bioregion. It is located entirely within the borders of Ontario, Canada. The main body of the bay lies east of the Bruce Peninsula and Manitoulin Island. To ...
. Downtown Toronto and Hamilton get most of their lake-effect snow when the wind comes from the southeast or east, over Lake Ontario. Such easterly winds are usually associated with a winter cyclone passing just to the south of the Great Lakes. When the wind is from the north, the
snowbelt The Snowbelt is the region near the Great Lakes in North America where heavy snowfall in the form of lake-effect snow is particularly common. Snowbelts are typically found downwind of the lakes, principally off the eastern and southern shores. Ca ...
runs north-south from
Grand Bend Grand Bend is a community located on the shores of Lake Huron in Southwestern Ontario, Canada. It is part of the Municipality of Lambton Shores in Lambton County. History Grand Bend is situated on the traditional territory of the Attawandaron ...
to
Sarnia Sarnia is a city in Lambton County, Ontario, Canada. It had a Canada 2021 Census, 2021 population of 72,047, and is the largest city on Lake Huron. Sarnia is located on the eastern bank of the junction between the Upper and Lower Great Lakes w ...
and
London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...
. Areas such as Lucan and Kincardine have experienced some of the heaviest snowsqualls from Lake Huron in this region. When the wind is slightly more westerly, the snowbelt runs from Tobermory,
Owen Sound Owen Sound ( 2021 Census population 21,612) is a city in Southwestern Ontario, Canada. The county seat of Grey County, it is located at the mouths of the Pottawatomi and Sydenham Rivers on an inlet of Georgian Bay. The primary tourist attractio ...
, and Grand Bend to as far south and east as
Arthur Arthur is a common male given name of Brythonic origin. Its popularity derives from it being the name of the legendary hero King Arthur. The etymology is disputed. It may derive from the Celtic ''Artos'' meaning “Bear”. Another theory, more wi ...
, Orangeville and Caledon. This snowbelt often reaches Kitchener and can affect the Halton and Peel regions of the Greater Toronto Area. These northwesterly winds usually also bring snow southeast of Georgian Bay, which can reach beyond
Lake Scugog Lake Scugog is an artificially flooded lake in Scugog, Regional Municipality of Durham and the unitary city of Kawartha Lakes in central Ontario, Canada. It lies between the communities of Port Perry and Lindsay. The lake has been raised and l ...
. A westerly wind sends lake-effect streamers east from Owen Sound to Gravenhurst,
Barrie Barrie is a city in Southern Ontario, Canada, about north of Toronto. The city is within Simcoe County and located along the shores of Kempenfelt Bay, the western arm of Lake Simcoe. Although physically in Simcoe County, Barrie is politically ...
, and
Orillia Orillia is a city in Ontario, Canada. It is in Simcoe County between Lake Couchiching and Lake Simcoe. Although it is geographically located within Simcoe County, the city is a single-tier municipality. It is part of the Huronia region of ...
, and may even reach as far south and east as
York Region The Regional Municipality of York, also called York Region, is a regional municipality in Southern Ontario, Canada, between Lake Simcoe and Toronto. The region was established after the passing of then Bill 102, An Act to Establish The Regional M ...
in the Greater Toronto Area. When the wind is from the southwest, lake-effect streamers from Lake Huron and Georgian Bay run from Noelville to Sudbury, Gravenhurst, and
Algonquin Provincial Park Algonquin Provincial Park is a provincial park located between Georgian Bay and the Ottawa River in Ontario, Canada, mostly within the Unorganized South Part of Nipissing District. Established in 1893, it is the oldest provincial park in Can ...
. Winds from this same direction coming over Lake Ontario cause squalls to come ashore from Cobourg through the Belleville area to Kingston, Ontario, Kingston and the Thousand Islands, with Prince Edward County, Ontario, Prince Edward County being the area most vulnerable to extreme snowfall amounts. Some snow bands can occasionally reach Quebec and Maine, while snow originating from Lake Erie, Lake Ontario, and even Lake Michigan can impact southern Ontario. Easterly winds primarily affect the Niagara Peninsula. Local lake-effect snowsqualls can occasionally occur downwind of Lake Simcoe when the lake is unfrozen, usually in early winter or late fall. Lake Superior has its own independent snowbelts, affecting Wawa, Ontario, Wawa, Sault Ste. Marie, Ontario, Sault Ste. Marie, Marathon, Ontario, Marathon, the Keweenaw Peninsula in Upper Michigan, and Pukaskwa National Park. Thunder Bay is usually not affected by lake-effect snow, unless it is associated with a winter storm.


Elsewhere in the United States

The southern and southeastern sides of the Great Salt Lake receive significant lake-effect snow. Since the Great Salt Lake never freezes, the lake effect can influence the weather along the Wasatch Front year-round. The lake effect largely contributes to the annual snowfall amounts recorded south and east of the lake, and in average snowfall reaching in the Wasatch Range. The snow, which is often very light and dry because of the semiarid climate, is referred to as the "Greatest Snow on Earth" in the mountains. Lake-effect snow contributes to roughly six to eight snowfalls per year in Salt Lake City, with about 10% of the city's precipitation being contributed by the phenomenon. Similar snowfall can occur near large inland bays, where it is known as bay-effect snow. Bay-effect snows fall downwind of Delaware Bay, Chesapeake Bay, and Massachusetts Bay when the basic criteria are met, and on rarer occasions along Long Island. The
Finger Lakes The Finger Lakes are a group of eleven long, narrow, roughly north–south lakes located south of Lake Ontario in an area called the ''Finger Lakes region'' in New York, in the United States. This region straddles the northern and transitional ...
of New York are long enough for lake-effect precipitation. The Texas twin cities of Sherman, Texas, Sherman and Denison, Texas, Denison are known, in rare instances, to have experienced lake-effect snow from nearby Lake Texoma due to the lake's size (it is the third-largest lake in Texas or along its borders). On one occasion in December 2016, lake-effect snow fell in central Mississippi from a lake band off Ross Barnett Reservoir. Oklahoma City even had a band of lake-effect snow off of Lake Hefner in February 2018. Owasso/Collinsville, Oklahoma outside of Tulsa, had lake effect snow off Oologah Lake, Lake Oolagah during a winter storm in February 2021. The Truckee Meadows and other parts of northern Nevada, which are normally in the rain shadow of the Sierra Nevada (U.S.), Sierra Nevada, when conditions are right, can have severe snowfall as a result of lake effect from Lake Tahoe. Recent severe examples of this phenomenon have occurred as recently as 2004, dumping several feet of snow in the normally dry region. The West Coast of the United States, West Coast occasionally experiences ocean-effect showers, usually in the form of rain at lower elevations south of about the mouth of the Columbia River. These occur whenever an Arctic air mass from western Canada is drawn westward out over the Pacific Ocean, typically by way of the Fraser Valley, returning shoreward around a center of low pressure. Cold air flowing southwest from the Fraser Valley can also pick up moisture over the Strait of Georgia and Strait of Juan de Fuca, then rise over the northeastern slopes of the Olympic Mountains, producing heavy, localized snow between Port Angeles, Washington, Port Angeles and Sequim, Washington, Sequim, as well as areas in Kitsap County, Washington, Kitsap County and the Puget Sound region. While snow of any type is very rare in Florida, the phenomenon of gulf-effect snow has been observed along the northern coast of the Gulf of Mexico a few times in history. More recently, "ocean-effect" snow occurred on January 24, 2003, when wind off the Atlantic, combined with air temperatures in the 30 °F range, brought snow flurries briefly to the Atlantic Coast of northern Florida seen in the air as far south as Cape Canaveral.


Elsewhere in Canada

Lake Winnipeg, Lake Manitoba and Lake Winnipegosis in Manitoba historically have seen lake-effect snow as early as late October, and it is common throughout early to mid-November. Towards the end of November, the lakes sufficiently cool and begin to freeze, ending the lake-effect snow. A brief period of lake-effect snow is also common near Great Bear Lake and Great Slave Lake in the Northwest Territories during early winter (usually early to mid-October); the lake-effect season for both lakes is very short, though. The lakes are frozen roughly eight months of the year, and as a result, have very little time to warm during the summer. Other small lakes such as Lake Athabasca in northern Saskatchewan and Lake Nipigon in northwestern Ontario produce early-season lake-effect snows. Smallwood Reservoir, a man-made lake located in Labrador, has on occasion generated lake-effect snow. The Canadian Maritimes, specifically Nova Scotia and Prince Edward Island, are often affected by such snow squalls when an Arctic winter airmass moves over unfrozen waters. In PEI, sea-effect snow is often generated when a cold north wind blows over the unfrozen Gulf of St. Lawrence, dumping heavy snow on the north shore. In Nova Scotia, a cold north-west wind can produce sea-effect snow over the Cape Breton Highlands from the Gulf of St. Lawrence, and the Annapolis Valley from the Bay of Fundy; in the latter case, the sea-effect snow season can continue all winter as the Bay of Fundy remains open owing to its extreme tidal currents. The east coast of southern Vancouver Island, British Columbia, experiences occasional episodes of sea-effect snow during winter due to cold easterly outflow winds from the British Columbia interior, typically through the Fraser Valley, crossing the always open waters of the Strait of Georgia.


Eurasia

Lake-effect or sea-effect snow occurs in other countries, near large lakes or large sea areas. In Eurasia, it occurs in the regions of the
Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Rom ...
in Georgia, Romania, Bulgaria and northern Turkey, the
Caspian Sea The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia ...
in Iran, the
Adriatic Sea The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to t ...
in Italy, the
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...
, the Irish Sea, the Aegean Sea, the Balearic Islands, and the
Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and ...
, as well as areas surrounding the Sea of Japan. Because the southern Black Sea is relatively warm (around 13 °C or 55 °F at the beginning of winter, typically 10 to 6 °C or 50 to 43 °F by the end), sufficiently cold air aloft can create significant snowfalls in a relatively short period of time. Due to its location on a peninsula between the Black Sea and the Sea of Marmara, Istanbul is very prone to lake-effect snow and this weather phenomenon occurs almost every winter. This type of precipitation is generated by the warmer Black Sea temperature and colder air temperature, over the Istanbul area. In February 2005, a lake-effect snowfall left of snow, and in March 1987, a three-week-long lake-effect snowfall accompanied with strong winds (lake-effect blizzard) left of snow in Istanbul. The snowfall in the eastern regions of the Black Sea is amplified by the orographic effect of the nearby Caucasus Mountains, often resulting in snowfall of several meters, especially at higher elevations. In the Adriatic regions of Italy and in the eastern Apennine Mountains, the sea-effect snow phenomenon with air masses coming from Northern or Eastern Europe (and Russia) can be incredibly heavy and can last for days. In the hills and mountains, it can result in snowfalls of several meters, as it happened in February 2012. These huge amounts of snow can also fall in short periods of time. In Northern Europe, cold, dry air masses from Russia can blow over the
Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and ...
and cause heavy snow squalls on areas of the southern and eastern coasts of Sweden, as well as on the Danish island of Bornholm, the east coast of Jutland and the northern coast of Poland. For the northern parts of the Baltic Sea, this happens mainly in the early winter, since it freezes later. Southeast Norway can also experience heavy sea snow events with east-north-easterly winds. Especially, coastal areas from Kragero to Kristiansand have had incredible snow depths in the past with intense persistent snowbands from Norwegian Sea (the coastal city of Arendal recorded in a single week in late February 2007). Although Fennoscandia is lined with an abundance of lakes, this type of snowfall is rare in these, due to the shallow freshwater freezing early in the cold interiors. One notable exception happened in the middle of May 2008, as Leksand on the since-long unfrozen lake of Siljan (lake), Siljan got on the ground. The Sea of Japan creates snowfall in the mountainous western Japanese prefectures of Niigata Prefecture, Niigata and Nagano Prefecture, Nagano, parts of which are known collectively as Snow country (Japan), snow country (''Yukiguni''). In addition to the Sea of Japan, other parts of Japan, as well as Korea and Shandong Peninsula, experience these same conditions. Because the Aegean Sea (Greece), is warm in the winter, when cold air masses from Siberia advance in the area, they pick up much moisture, resulting in heavy snowfalls in eastern Central Greece, eastern Thessaly, eastern Peloponnese, south-eastern Chalkidiki, the Cyclades, and Crete (more commonly in the mountainous areas). In 2008, a severe snowstorm blanketed Athens, dropping of snow and causing huge traffic jams. Moving of polar or Siberian high-pressure centers along Caspian Sea regarding to relatively warmer water of this sea can make heavy snowfalls in the northern coast of Iran. Several blizzards have been reported in this region during the last decades. In February 2014, heavy snowfall reached on the coastline in Gilan Province, Gilan and Mazandaran Province, Mazandaran provinces of Iran. The heaviest snowfall was reported in Abkenar, Gilan, Abkenar village near Anzali Lagoon. File:Caspian-lake-effect.gif, IRIMO radar animation of lake effect snow in southern coast of Caspian Sea in the north of Iran File:Caspiansatelliteimage.jpg, Lake-effect clouds over
Caspian Sea The Caspian Sea is the world's largest inland body of water, often described as the world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad steppe of Central Asia ...
on January 7, 2008 File:Lake effect pic.jpg, Lake effect snow in Athens on February 16, 2021 File:Lake effect pic 1.jpg, Lake effect snow in Athens on February 16, 2021


United Kingdom

In the United Kingdom, easterly winds bringing cold continental air across the
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...
can lead to a similar phenomenon. Locally, it is also known as "lake-effect snow" despite the snow coming in from the sea rather than a lake. Similarly during a north-westerly wind, snow showers can form coming in from the Liverpool Bay, coming down the Cheshire Plain, Cheshire gap, causing snowfall in the West Midlands (region), West Midlands—this formation resulted in the white Christmas of 2004 in the area, and most recently the heavy snowfall of 8 December 2017 and 30 January 2019. A similar phenomenon can affect the city of Inverness in the Scottish Highlands, where cold north-east winds cause heavy snow to form in the Moray Firth; this was the case with the White Hogmanay of 2009, which caused the street party to be cancelled. Northerly and north-westerly winds can cause the effect to occur over the Irish Sea and Bristol Channel feeding snow into South West England and eastern Ireland. Western Scotland and northern Ireland can also see snow showers from a north or north-westerly wind over the Atlantic. Since the North Sea is relatively warm (around at the beginning of winter, typically by the end), sufficiently cold air aloft can create significant snowfalls in a relatively short period of time. The best-known example occurred in January 1987 South-East England snowfall, January 1987, when record-breaking cold air (associated with an upper low) moved across the North Sea towards the UK. The end result was over 2 ft of snow for coastal areas, leading to communities being cut off for over a week. The latest of these events to affect Britain's east coast occurred on November 30, 2017; February 28, 2018; and March 17, 2018; in connection with the 2018 Great Britain and Ireland cold wave. The second event of winter 2017/18 was particularly severe, with up to falling in total over the 27th–28th. Similarly, northerly winds blowing across the relatively warm waters of the English Channel during cold spells can bring significant snowfall to the French region of Normandy, where snow drifts exceeding 10 ft (3 m) were measured in March 2013. File:Snow-chart.png, Chart showing the sea-effect snow event of January 1987 in the UK: A continuous stream of showers deposited over of snow over SE coastal regions. File:Lakeeffect.png, NetWeather radar image showing "lake-effect" snow over Kent and northeast England


See also

* Horizontal convective rolls * OWLeS, Ontario winter lake-effect systems * Planetary boundary layer * Sea smoke Warnings about lake-effect snow: :United States: ::* Lake effect snow advisory ::* Lake effect snow watch ::* Lake effect snow warning ::* Severe weather terminology (United States) :Canada: ::* Snowsquall warning ::* Severe weather terminology (Canada)


References


External links


National Weather Service Official Lake Effect Page
based in Buffalo, NY
Lake effect forecasting

Video of a snowsquall timelapse while driving on Highway 407 ETR in Greater Toronto




, Great Lakes Environmental Research Laboratory
A BBC forecast of lake effect snow in the UK in 1991
{{Severe weather terminology (United States) navbox Climatology Snow or ice weather phenomena Upper Peninsula of Michigan fr:Bourrasque de neige#Bourrasques en aval de plans d'eau