Great Lakes Snow Absent So Far This Winter
January 8, 2013
By WeatherBug Meteorologist, Chad Merrill
While the Northwest has been in a wintry pattern for much of the season the same can`t be said for the remainder of the U.S. As a matter of fact, even the typically snowier Great Lakes snow belts have remained brown this winter.
In order to understand why the Great Lakes snow belts have been dry, it`s necessary to understand how lake effect snow forms
. When cold, Canadian air rushes across the warmer Great Lakes, the air picks up moisture, forms clouds and then deposits the moisture as snow. The colder the winds are blowing across the lake, the more snow that will fall downwind of the lake.
The progressive nature of weather systems moving across the Great Lakes this winter has put a lid on lake-effect snow. While fronts have pushed colder air across the Great Lakes, they`ve had a tendency to be immediately followed by high pressure and lighter winds that shut down the lake-effect machine. In addition, there hasn`t been an Arctic blast strong enough to generate prolific heavy lake-effect snow bands.
Here is a list of top locations that typically get most of their snow from lake-effect. Notice the snowfall departure since fall for each city in the right hand column.
|Great Lakes City
|Grand Rapids, Mich.
|South Bend, Ind.
|Sault Ste. Marie, Mich.
Lake-effect snow typically happens from late-autumn to early-winter. By early to middle January in an average winter, the temperature departure between the cold, Arctic air and the sheets of ice on the lakes is so miniscule that air can`t pick up enough moisture to generate snow.
As of early January, there is less than 10 percent ice cover on each of the Great Lakes. While lake-effect snow normally diminishes in January, the mild winter that has kept the Great Lakes warm so far, meaning any upcoming cold outbreak could produce heavy snow in the snow belts. This would help chip away at the ongoing snow drought.
In a year with normal temperatures, typically less than half of Lakes Ontario and Michigan freeze over while up to 90 percent of Lake Erie can be frozen by late January. Due to Lake Superior`s large size, it rarely completely freezes over and if so, just for a few hours. The last time the Great Lakes have even come close to becoming a nearly solid shield of ice was the winter of 1978-79. As a matter of fact, the stretch of winters from 1976-1979 were cold enough to form many ice sheets on the Great Lakes.
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Story Image: Vehicles are stranded on the New York State Thruway during a lake-effect winter storm in early December 2010. (David Duprey, AP)
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