FARGO — The cold weather has finally begun the process of ice formation on area lakes, a very dynamic process due to the fact that water has its highest density at around 39 degrees Fahrenheit. As air temperatures drop below freezing in fall and early winter, the higher heat capacity of water requires more time for lakes to cool. As a lake’s surface approaches 39 degrees, it sinks, allowing warmer water from the depths to rise to the top. This water then cools and sinks, until the total depth of the lake finally reaches 39 degrees.

At this point, water near the surface no longer flows as it cools. so the lake can start to freeze. Because of the heat coming from Earth, it is unusual for all but extremely shallow lakes in our climate to freeze. The ice will be thicker in winters where the cold persists well before the snow becomes deep.

John Wheeler is chief meteorologist for WDAY, a position he has held since May 1985. Wheeler grew up in the South, in Louisiana and Alabama, and cites his family’s move to the Midwest as being important in developing his fascination with weather and climate. Wheeler lived in Wisconsin and Iowa when he was a teenager. He attended Iowa State University and graduated with a bachelor’s degree in meteorology in 1984. Wheeler worked about a year at WOI-TV in central Iowa before moving to Fargo and WDAY.