One of the common questions I get is: “Does Lake Michigan ever freeze over completely?”
The short answer is yes. A more concise answer would be rarely. The last time the lake froze completely was in 1992, so it’s been 20 years.
I’ve certainly seen what looked to be a completely frozen lake in those interim years however. Here’s what happens. The surface lake water drops to 32 degrees. That means if it’s calm, ice forms on subfreezing nights.
|This is a current shot of an Indiana Lake Michigan beach.|
Add to this the fact that water can exist in both liquid form and solid form at 32 degrees. So the ice that forms on calm nights, in bays or on the upwind side of the lake doesn’t soon melt. Instead, it blows with the wind and if the wind direction stays the same for long enough, it all piles up on the downwind side of the lake. When the wind changes, the ice pack blows to the other side of the lake. By early February, if you are on a downwind shore, you probably can’t see to the open water several miles away. The jagged peaks of the pack ice makes it look as though polar bears should be roaming there hunting seals.
As winter progresses, the amount of ice increases. In an average year, half or more of the lake’s surface is covered by this growing ice pack, and thanks to frequent north winds in the winter months, a lot of the ice pack is on our end of the lake.
In addition to the ice pack, miniature glaciers form along Indiana’s beaches and breakwalls. Even before the lake water cools to 32 degrees, early winter storms with subfreezing temperatures and onshore winds send big waves crashing to our shores. The waves pile up, spray wets down rocks, beaches, piers and lighthouses. Each wave splashes a wet layer which quickly freezes before the next wave comes. Soon inches of ice encapsulate the shore and shoreline features. Inches of ice become feet of ice and until the pack ice forms to guard the shore, beaches and walls may have 10 feet or more of ice extending to the water’s edge.
So Lake Michigan normally doesn’t often freeze completely, but ice is a regular feature that helps mold and shape the lake’s environment.