Lake-Effect Snow Climatology in the Great Lakes Region
The distribution of snowfall in the Great Lakes region resulting from lake-effect snowfall is dependent upon several factors: the position of the storm tracks, the degree and variations in lake water temperatures, the extent of ice coverage, prevailing wind directions and the frequency of strong wind speeds. Topographic contrasts to the lee of each of the Great Lakes also affect the intensity and spatial distribution of lake effect snowfall. Lake effect snowfall contributes between 30% and 50% of the annual winter snowfall on the eastern and southern shores of the Great Lakes.
Seven unique snowbelts are associated with the five Great Lakes: 1) the Southeastern Lake Superior Snowbelt extending almost 500 km (300 miles) along the northern shores of Upper Michigan; 2) the Eastern Lake Superior Snowbelt located in Ontario north of Ste. St. Marie; 3) the Eastern Lake Michigan Snowbelt, covering the western shore of the State of Michigan and northern shore of Indiana; 4) the Southeastern Lake Huron Snowbelt in Southwestern Ontario; 5) the Georgian Bay Snowbelt along the eastern shores of Georgian Bay in Central Ontario; 6) the Southeastern Lake Erie Snowbelt in the uplands of Allegheny Plateau back from the lake front in New York, Pennsylvania and northeastern Ohio; and 7) the Southeastern Lake Ontario Snowbelt, centred on Tug Hill Plateau immediately east of Lake Ontario in New York.
In Ontario, total snowfalls along the shorelines of Lake Superior, Lake Huron and Georgian Bay reach 300 to 400 cm ( 118-157 in), most of which is due to lake-effect snowfall. In these areas, the topography rises from the shoreline to nearby highlands which encourage heavier snowfall: about 17 cm for every 30-metre rise.
One memorable storm hit the snowbelt southeast of Lake Huron around London, Ontario in late 1977. During the three-day period from December 7 to 9, lake-effect snow squalls, driven by 100 km/h (60 mph) winds, dropped over 100 cm (39 in) of snow on the region. The snowfall was accentuated by heavy blowing and drifting.
United States Regions
The climatological impact would appear to be greatest in the United States across the snowbelts of Michigan. In Michigan, snowbelts are nearly continuous along the state's shores of Lakes Michigan and Superior. Snowfall amounts are, in general, least in southeast Michigan, the area furthest from Lake influence, and greatest in the northwest portion of the Upper Peninsula with secondary high accumulation zones in the lee of Lake Michigan.
The most spectacular lake-effect snow squalls occur eastward of the lee shores of Lake Ontario and Lake Erie in New York, Ohio and Pennsylvania. Lake-effect snowfalls in this snowbelt are generally quite local, averaging 30 km (20 miles) across and from 16 to 112 km (10 to 70 miles) in depth, but can accumulate snows at amazing rates.
For example, in a sixteen hour period crossing December 7-8, 1958, 102 cm (40 in) of lake-effect snow fell at Oswego, New York on the southeastern shore of Lake Ontario. During this intense storm which lasted over northern New York from December 5 to 11, a total of 183 cm (72 in) accumulated just south of Buffalo. Not to be outdone, Bennetts Bridge, 50 km (30 miles) east of Oswego, reported a snowburst of 130 cm (51 in) in 16 hours on January 17, 1959. In February (4-5) 1972, an accumulation of lake-effect snow dropped 142 cm (56 in) on Oswego, trapping the participants of the annual Eastern Snow Conference!
But the granddaddy of all lake-effect snows in the Great Lakes basin appears to be the accumulation that hit Oswego, New York over the five day period 27-31 January 1966 (some of the snow may have been due to a blizzard moving up the coast). By the time the snow abated, 259 cm (102 inches) of snow had accumulated, about two thirds of the city's annual total. About half of that total fell on the 31st.
The persistent flow of cold air over the eastern Great Lakes region during the Winter of 1976-77 produced one of the most spectacular lake-effect snowfall seasons. To put it into perspective, U.S. National Oceanic and Atmospheric Administration (NOAA) scientists examined the ten previous winters and determined an average of 25 days with purely lake-effect snowfall in the lee of Lakes Erie and Ontario. In Winter 1976-77, the total was 51 days. The first struck in October. From November 29 to December 2, Buffalo was paralyzed by an official 102.9 cm (40.5 in) but greater amounts were observed south and east of the city.
The total snowfall for January 1977 in Watertown, New York was 230.6 cm (90.8 in), and Hooker, New York was buried under 378.5 cm (149 in). For the season, total snowfall in Buffalo was a record 506.5 cm (199.4 in) with one period of 53 consecutive days with snowfall, exceeding the previous record by 23 days!. The total could have been higher, but Lake Erie froze completely over by late January. Hooker accumulated the greatest amount of snow every observed in the lee of any of the Great Lakes to that time 1185.9 cm (466.9 in)! These total were accumulated in a winter where most areas of the U.S. Northeast reported a drier than normal winter.
Even the following winter, which has been called the Cold, Snowy Winter of 1977-78, could not exceed the totals in the Erie and Ontario snowbelts accumulated during 1976-77. Yet records were set across the U.S. east of the Mississippi, from Texas across the Midwest and New England. The combination of cyclonic and lake-effect snows did set a new record for a single month at Bennetts Bridge: 487.7 cm (192 in).
The Snowy Seventies
The potential impact of lake-effect snowfall in the Great Lakes region can best be illustrated by looking at the snowiest major cities in the United States in the 1970s, a decade known as the Snowy Seventies. The period was characterized by a drop in global air temperature and dramatic increase in snowfall across the Northern Hemisphere. In the Great Lakes region, three winters (1975-76, 1976-77, 1977-78) particularly stand out which were characterized by very cold temperatures beginning in November and very strong north/northwesterly winds. Impacts may have been higher if not for the fact that Lake Erie and Lake Ontario froze mostly or completely over.
Buffalo, New York led the list with 2819 cm (1109.8 in) of total snowfall over the decade with Rochester, New York second at 2728 cm (1074 in). (The smaller city of Syracuse, New York recorded 3043.7 cm (1198.3 in).) The third on the list was Salt Lake City, Utah at 2078.5 cm (818.3 in), itself located on the shoreline of a large lake. Fourth was Albany, New York -- 1775.5 cm (699.1 in) -- and Cleveland, Ohio, sixth -- 1449.6 cm (570.7 in).
Update on Notable Lake-Effect Snowstorms
On November 20-23, 2000, the Buffalo, New York area was hit with a 60-hour lake-effect snowstorm. During the period, the storm, named Chestnut by the local National Weather Service office (which began naming significant events in 1998 for archiving purposes) dumped up to 79 cm (31 inches) in Stockton. It was the most widespread
and significant November lake-effect storm since 1996 when a longer lasting storm dropped about a metre (over 3 feet) of snow over Chautauqua County.
According to the Buffalo NWS office: "'Chestnut' was a classic and severe lake effect storm." The storm had frequent lightning as snow showers blossomed into heavy thunder snowpellet showers . Snow falling at the rate of 5-10 cm (2-4 inches) per hour for several hours focused on the most densely populated area of upstate New York. The timing (from 1 to 9 pm) of the most intense snowfall could not have been worse as area workers trying to leave early clogged roads. Thousands were reported to have spent the night in autos or stores. Many schoolchildren and school buses became trapped as well. It was the most disruptive storm in the Buffalo area since the Blizzard of ‘77, and coming in the pre-Thanksgiving period ruined many holiday plans for the million-plus residents of western New York.