Lake effect snow from the Great Lakes occurs when conditions of evaporation and cold upper air currents slide over the region. Water retains on to heat more than air. This causes some open water in the Great Lakes to evaporate into the air and warm it. Rising up into the atmosphere this warm, wet air cools as it travels.

The lake effect snow explained in a simple video showing the major areas of the Great Lakes region where this type of weather pattern prevails. This pattern occurs when snow falling on the lee side of a lake, generated by cold dry air passing over warmer water, especially in the Great Lakes region.

How Lake Effect Snow Forms

Lake Effect Snow – From NOAA

The cold dry air, often originating from the west and Canada, moves across the open waters of the Great Lakes. As the cold air passes over the unfrozen relatively warm waters of the Great Lakes, warmth and moisture are transferred into the lowest portion of the atmosphere. The air rises, clouds form and grow into narrow band that produces 2 to 3 inches of snow per hour or more.

Wind direction is also and indicator on will receive lake effect snow. For example, heavy snow may be falling in Caseville, while the sun may be shining in Bad Axe. The physical barrier that Sand Point represents also has some impact on weather patterns on south shore of Saginaw Bay.

Lake Effect Snowbelt Map

Lake Effect Snowbelt Map – University of Michigan

The greatest accumulations typically occur in Canada on the Bruce Peninsula, and within Georgian Bay. The Upper Thumb also experiences lake-effect precipitation during prevailing southwest wind winter storms or when Saginaw Bay is significantly frozen over.

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