Lake Turnover

Once again, our most visited page on the website is Water Levels on Horseshoe, and this time of year, the most interesting data point is the water temperature.  If you’ve been keeping an eye on it, you’ll notice that the temperature was holding steady at 39 degrees, which is when water reaches its maximum density. The unique property of water reaching maximum density above its freezing point is the driving force behind the natural process of "lake turnover," which typically occurs in the spring and fall. 

During the fall, as the surface water cools, it becomes denser and sinks, forcing the less dense, warmer water from the bottom to the surface. This process continues until the entire water column reaches a uniform temperature and density of around 39.2°F, allowing the wind to mix the layers.  This mixing is crucial for the health of aquatic ecosystems because it redistributes oxygen throughout the lake and brings nutrient-rich sediment from the bottom to the surface.

It looks like nothing is happening, but it’s one of the most unique phenomena in nature!

Look for the lakes to start icing over in the coming days, especially with the cooler temps.  And remember, report ice in dates on our Facebook page and include photos to be entered into a drawing for SRCLA swag!

Let’s track our ice in and out dates!

In the spring of 2025, we had a question about ice out dates on the Chain, which we did not track at the time.  Other than MN DNR records (which are contributed by citizens to their Facebook page), we had no official record for our lakes!

 We want to change that!  The ask?  Monitor your lake, and when you see conditions matching the official ice-in definition (you can find it on our new Ice In/Ice Out page on the website!), reply to this Facebook post with 1) lake name 2) date of observation 3) photo if possible 4) did you go the extra step and post to the DNR Facebook page?

All valid entries will be entered in a drawing for an SRCLA Goodie Bag. 

General ice thickness guidelines

The DNR does not measure ice thickness on Minnesota lakes. Your safety is your responsibility. Learn about the different ways to check ice thickness before heading out. The MN DNR website is a great resource!