I am born and raised in Michigan, and other than a stint in the US Air Force, I have called this state home all of my life. Living in the Detroit area on the eastern side of the state, however, I never experienced a lake effect snow storm until I moved to Harbor Springs in 2007.
This past weekend we visited my parents downstate. We left on Saturday morning to a light dusting on the lawn. When we returned Sunday night, we discovered 12-14″ blanketing our driveway. When we got home from work on Monday, another 4-6″ fell. In less than 48 hours, nearly 20″ of snow has fallen in Harbor Springs. And that is nothing compared to the 42″ that fell in the UP town of Ishpeming in under 24 hours.
Snow…lots and lots of snow…are a way of life for me and my family. For the first few years we lived in Harbor Springs, the forecast of ‘lake effect snow’ sent us in a panic. Today, we not only keep calm in the face of massive amounts of snow, we often look forward to it.
There is actually two ways that we get snow in Northern Michigan.
The first is a weather system that most often rolls in from the west (although we are sometimes surprised by weather systems that come from the east or south). These systems carry moisture from far away places and drop it in varying amounts. This is the same type of snow that falls in Wisconsin, Minnesota, and the eastern part of the lower peninsula.
The second, and more dramatic, way we get snow is from our lakes. Lake-effect snow is a unique weather phenomenon requiring conditions that occur in only a handful of locations worldwide. The Great Lakes region are the most susceptible place for these events in North America, especially the southern Lake Superior, eastern Lake Michigan, and eastern Lake Erie shorelines.
Lake-effect snow forms when cold air travels over the warm waters of a large lake. The warm lake water evaporates as the cold air passes overhead, heating the bottom layer of the air mass. Because warm air is lighter and less dense than cold air, the warm air rises and cools. The moisture that evaporates into the air condenses and forms clouds. When the clouds reach land, the cloud cools and dumps all of that moisture in the form of snow. The release of snow is concentrated and intense. It is common for several inches of snow to be falling in one area, while a few miles away it is snow free and sunny.
Depending on weather conditions, bands of snow can hover over one location for several hours or even days (as we are currently seeing in Northern Michigan). It is not uncommon to see snowfall rates of up to 5″ an hour along the shore, while 20-25 miles inland there is only blue skies.
The good news is that once the lakes freeze, usually in January or February, we see a dramatic decrease or even an elimination of lake-effect snow.
What you are seeing in the photograph above is an image of a massive lake effect snow system from last winter. If you look closely, you will see that the clouds are thickest right at the western shoreline of Lake Michigan and along the eastern portion of Lake Superior. Clouds are covering the entire state, and snow is falling from those clouds, but they are heaviest along the shoreline.