Lake-Effect Snow

What is lake-effect snow?
Lake effect snows are a small scale (mesoscale) weather phenomena analogous to a thunderstorm in the summer. Like a thunderstorm they are convective in nature.

Where does lake-effect snow occur?
In general they occur on the downwind shores of the Great Lakes but also can occur over other regions of the world. The Great Lakes lake effect snows though tend to be the most prolific.




What causes lake effect snow?
The cause of lake effect snow is when very cold arctic or polar air moves across the warmer (unfrozen) Great Lakes. This cold air mass is made unstable by the warmer air over the Great Lakes causing the cold airmass to become very unstable. The greater the temperature difference between the water temperature of the underlying Great Lakes and the cold air mass moving across the lake, the greater the instability. This is called the air-lake (temperature) difference.