Lake Effect Snow

Caitlin Dempsey

Updated:

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.


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A diagram showing how lake effect snow happens with blue arrows for cold air and red arrows for warmer air as they pass over a lake and on the other side of the lake is snow falling.
Lake snow effect happens when cold, dry air moves over a large lake with much warmer water temperatures and snow falls downwind of the lake. Diagram: Caitlin Dempsey using Canva elements.

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.

A satellite image show snow covering the land around the Great Lakes.
A lake effect snow event on December 9, 2006 around the Great Lakes. Satellite image: NASA Terra, public domain.

This satellite image taken on March 1, 2022 shows how the area around Lake Erie was covered in snow after a late season lake effect snow event that had happened between February 27-29, 2022.

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.

A satellite image showing snow covering areas of Ohio, Pennsylvania, and New York just south of Lake Erie.
The February 27-29, 2022 lake effect snow event left areas south and southeast of Lake Erie covered in snow. Image: NASA, public domain.

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.

Satellite image of the Aral Sea showing snow towards the top of the image and tan landscape at the bottom.
Snow along the western edge of the Aral Sea after a lake effect snow event. Image: NASA, December 27, 2020, public domain.

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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.