Lakes that are large enough can have a dramatic effect on the production of snow and create an extreme snowfall event.
This phenomenon is known as “lake effect snow” (also spelled lake-effect snow).
Lake effect snow happens when cold, dry air flows over a large lake. The air current causes evaporation from the warmer waters to rise into the colder air. As the now water-laden and warmer air continues onshore, it cools and the water falls to the ground as snow.
How the lake effect produces so much snow
Lake effect snow requires a large difference between the cold, dry air sweeping over the lake and the warmth of the body of water. A temperature difference of 25 degrees Fahrenheit (14 Celsius) or more sets up conditions that can fuel large deposits of snow.
Other factors that influences snowfall is the length of the lake that the air passes over and the speed at which the air is flowing. The longer the path of the air over the lake, the more that water becomes laden with water moisture from evaporation. Faster air will pick up less water moisture than a slower moving air current.
The result is the formation of heavy snow bands down wind of the lake.
The Great Lakes and lake effect snow
One part of the United States where lake effect snow is common is the Great Lakes area.
Cold winds arrive from Canada and flow over the vast open waters of the Great Lakes before depositing snow down wind along the banks.
Satellite imagery taken after a lake effect snow event over the Great Lakes shows snowbelts on the leeward side of the lakes.
This satellite imagery, acquired on December 9, 2006 from NASA’s Terra satellite, shows the aftermath of a lake snow effect event over the Great Lakes area.
Up to 2 feet (0.6 meters) of snow fell in towns like Carthage and Croghan in upstate New York. Northwestern Pennsylvania and northern Ohio also experienced snowfall.
In parts of northwestern New York and Pennsylvania, lake effect snowstorms frequently cause up to two feet of snow to fall in a matter of 24 hours.
Buffalo, New York is renowned for receiving a lot of snow each year in large part due to the lake effect snow phenomenon.
Buffalo averages a little under eight feet of snow, 95.4 inches, each year. For the 2021-2022 seasons, which runs from from July to June, Buffalo received 97.4 inches of snow.
Areas of the United States that frequently experience lake effect snow
In the United States, the Great Salt Lake in Utah, northern Wisconsin, western Michigan, northwestern New York, and northwestern Pennsylvania frequently experience lake effect snow.
Lake effect snow typically happens during late fall when large lakes still retain much of the summer heat but colder air is descending from the north. By February, areas like the Great Lakes start to experience a reduction in days with a lake effect snow event.
Lake effect snow around the world
Other areas of the world with large lakes and cold winds, like the Aral Sea, can experience lake effect snow events.
This satellite image shows snow deposited along the western edge of the southern portion of the South Aral Sea. Cold winds in this region of Central Asia blow from east to west.