Nature Note - Mixing Begins

The twice annual mixing of the lake’s warm and cold layers begins in earnest once the water temperature dips below 40⁰ F. At that point, the lake water temperature and thus density becomes relatively uniform from top to bottom. When the lake reaches the uniform top to bottom temperature, wind and storms cause the water to turnover. This mixing helps oxygenate the deeper water and re-circulate nutrients up to the shallower waters. Since 2001, the average date at which the lake has reached the 40⁰ F threshold (according to data collected from the King St. lake gage in Burlington) has been December 8^th with an early date of November 24^th in 2008 and a late date of December 26^th in 2001. Shallower parts of the lake will cool sooner. Once the lake freezes over, it is again layered, this time with colder water (ice) over warmer water.