Lake effect snow can fall heavily in one place while the sun shines a mile or two away. Check the forecast and alerts for your exact location before driving.
How it forms
Cold air, often from Canada, moves across the open water of the Great Lakes. The lake water is relatively warm and unfrozen, so it transfers heat and moisture into the lowest layer of the atmosphere. That air rises, clouds form and grow into narrow bands, and those bands produce snow.
Where it falls
Wind direction determines which areas get lake effect snow, and the physical geography of the land and water also matters. Snow can fall heavily in one place while the sun shines a mile or two away.
How heavy it gets
Snow bands can produce 2 to 3 inches of snow per hour or more. It is common across the Great Lakes region during late fall and winter.
Stay informed
Because the bands are so local, check winter weather alerts for your exact location. See our winter storm hub and the winter driving guides.
Check your own location
See current official alerts and the impact for your ZIP code.
Common questions
What causes lake effect snow?
Cold air moving across relatively warm, unfrozen lake water picks up heat and moisture. The air rises, clouds form and grow into narrow bands, and those bands produce snow.
Why is lake effect snow so bad?
The bands are narrow and intense: the National Weather Service says they can produce 2 to 3 inches of snow per hour or more, and snow can fall heavily in one place while the sun shines a mile or two away.
When does lake effect snow happen?
It is common across the Great Lakes region during late fall and winter.
Sources
Reviewed by the Storm Incoming editorial team on October 27, 2026. Follow local emergency officials if their instructions differ.