Mystery of the canal freeze, thaw revealed

Jeff Broddle | Cadillac News Year after year, the canal in Cadillac turns to ice before the lakes freeze over and thaws again after the lakes turn to ice. DNR fisheries biologist Tom Rozich said there is a scientific explanation for the natural occurrence.

CADILLAC - To many, it is a mystery.

Year after year, when the snow sweeps in the area and thermometers dip down below freezing, a sheet of ice forms over the canal connecting lakes Cadillac and Mitchell.

Weeks later when the lakes concede to the icy, cold temperatures and form an icy covering of their own, the canal mysteriously thaws and remains unfrozen for the rest of the winter.

The big question is why?

For years the question went unanswered. But science prevailed and proved the answer to the phenomenon did indeed have a logical explanation.

The first thing a person must understand, according to Department of Natural Resources fisheries biologist Tom Rozich, is the physical properties of water. Water is most dense (heaviest) at 39 degrees F and lighter above and below this temperature.

Therefore, in the winter, the lighter (or cooler) water molecules float to the top. As the weather gets cooler, the water closest to the top freezes and then turns to ice.

“Because the canal is shallower, it has less volume and is able to cool and freeze quicker,” Rozich said. “That is why ice forms on the canal before the lakes.”

When the lakes catch up and start the freezing process, the warm water on the bottom of the lake is then forced to leave, as the growing ice cover moves the water. The water movement happens to be toward the canal in the cases of lakes Mitchell and Cadillac.

“That warmer water forms a current through the canal which melts the ice in the canal,” Rozich said. “And the canal stays open all winter long, although there might be some ice near the shore when it hits 10 below.”

Not only was this a mystery to local folks, but to the world as well when it was mentioned on Ripley's Believe It or Not, according to local author Mark Jager. He mentioned the phenomenon in book one of his series called “Mystic Michigan,” which explores bizarre happenings in the state.

In the book he mentioned that after receiving updated information and proof of the phenomenon, the mystery of the canal will be used in Ripley's syndicated cartoon form.

Your local connection

The canal between lakes Cadillac and Mitchell mysteriously freezes before the lakes and thaws once the lakes freeze year after year.

After many decades of wondering, the scientific answer was finally revealed. The natural occurrence has to do with the ice pushing the warmer weather below, where it then is forced somewhere - which happens to be the canal.

tberkebile@cadillacnews.com | 775-NEWS (6397)