Temp of water below ice?

[Burchoid]

I have a question.

In lakes that are frozen over, what is the tempurature of the water below the ice when its been below freezing outside? Does it change at all at different depths? Has anyone ever taken a temp reading?

Science says that water is most dense at 4 degrees celsius or 39.2 degrees fahrenheit. The water near the top of the water column, or the bottom of the ice, should be colder than 4 degrees celcius and less dense, leaving this slightly warmer water underneith.

I am just curious what people have noticed when taking temp readings in the winter below the ice.

[Fastlane]

I think I know what you are trying to get at and I believe what you are thinking is correct to a certain point. A lot of lakes we have have inlets and outlets which also create currents in lakes, I suppose underground aquifers can also play with the temps of the water in the column. With this in mind, I think just taking the temp of the watercolumn in many lakes can vary from spot to spot.

However, I believe you are correct in that if currents didn't play a role, the coldest water is right under the ice.

These images complimentary of (http://www.chem1.com/acad/webtext/pre/density.html)

[wiskodie1]

ground temps below the frost line stay around 57 degrees all year round, the ice and snow act as an insulation to help keep the water warmer then the air above it, water close to the lake bottom will be heated up from the lake bottom and then start to rise to the surface just like hot air, at the same time cold water that is close to the surface will sink to the bottom, now since the water is always moving up and down under the ice, it never reaches the 57 degrees lake bottom temp and depending on how much snow is on the ice(insulation) and the air temp will determine the rate that ice will freeze, there is also currents in the lake that will mix water from the bottom and top faster then normal which can lead to higher water temps and help undercut the ice making for thin spots. Over all its safe to say that the deeper the water the warmer you can expect it to be, the thermal layer in the lake, is the point at which the hot deep water and cold top water meet, its depth will change over the winter depending on air temp and snow cover. overall lake temps will depend on, lake depth, current, snow, and air temps. because of this no two lakes will have the same water temps, or ice conditions.

well hope that helped

[john.wells]

You can go to the Minnesota DNR HSOforum and type in "the wonder of water" in the search box. Click on the link for a neat little article that describes the properties of water. It is geared towards kids, but is great for big kids (like me ) as well.

[PerchJerker]

I'm trying out a camera right now that has a temp gauge built into it. 37.4 degrees on the bottom where the camera was - this was on Lake Waconia on Sunday.

[Burchoid]

So the deeper parts of a lake could potentially be warmer water... I wonder how this could relate to fishing in the winter? hmmmm