Lake effect snow is a unique meteorological event occurring most commonly in areas south and east of the Great Lakes in the northern United States. Many travelers unfamiliar with the phenomenon are caught off guard when driving through these areas during a lake snow event. Driving the I 90 corridor through Ohio, Pennsylvania and New York can be a harrowing experience when the lake snow machine is cranked up.
What causes "lake effect"
Lake effect snow requires several specific conditions to generate the massive amounts of snowfall it is famous for. Per the NOAA, lake effect snow is possible when cold arctic air sweeps across warmer bodies of lake water. Colder air will not hold moisture, but, as this cold air moves across the open body of warm water, the air is warmed. This then allows the air to carry the evaporating lake water, setting up the event. As the relatively warmer lake-warmed air moves past the lake and over land, it cools quickly. This rapidly cooling air is unable to hold the moisture and releases it in the form of snow in a concentrated area.
The release of moisture is concentrated and dramatic, and it is common for an area just a few miles from the area where the snow is falling heavily to be snow free and sunny. The areas of land where this concentrated amount of snow falls are known as "snow belts." These snow belts are determined during each event by the wind direction and speed as well as air temperature.
These conditions are only found in a few locations in the United States. The Great Lakes region is the most susceptible to these snow events due to the large bodies of open water exposed to arctic air in the winter months. According to The Weather Channel, lake effect can be experienced in Utah's Great Salt Lake region, as well.
Lake effect's dramatic results
As mentioned, each storm will form "snow belts" where the concentrated snow is most likely to fall. While it is true that there will be some shifting of these snow belts due to prevailing weather patterns, there are certain areas where the snow belts will regularly form. As described by The Weather Channel, a rise in elevation can amplify the effect. As an example, the Tug Hill Plateau east of Lake Ontario receives between 200 and 300 inches of snow each winter season!
The combination of location relative to open water, elevation and exposure to arctic air can result in wide discrepancy in average snowfall for locations relatively close to one another. A great example of this dramatic difference in snowfall can be seen comparing two Ohio cities separated by only 10 miles. Mentor, Ohio, is a city on the southern shores of Lake Erie but falls too close to the lake to receive the bulk of lake effect snow during the season. Mentor's average snowfall is 36 inches. Chardon, Ohio, is just 10 miles away from Mentor, but the elevation is higher and it sits further downwind from typical winter storm patterns. That extra distance allows the moist air to rise and cool more, making it less able to hold the moisture it collected over Lake Erie. As a result, Chardon's average snowfall is a whopping 111 inches!
Lake effect is a unique weather phenomenon requiring conditions that occur in very few locations in the world. In these places, the perfect conditions create snowfall amounts dramatically different from surrounding areas causing rapidly changing and potentially dangerous travel conditions during the winter months. So the next time you are out shoveling the four inches on your driveway, cursing winter, remember the poor folks in Chardon. They are probably trying to dig out from under a foot of snow.