<p>A snippet from the linked question:</p>
<blockquote>
<p>Fred says:</p>
<p>Also, while water is flowing its potential energy is constantly being converted to heat energy that resists freezing on the molecular level and subsequent crystallization.</p>
<p>For flowing water to freeze, the temperature would have to be exceptionally cold</p>
</blockquote>

CC BY-SA 3.0
2016-02-10T07:39:45.403Z
2016-02-10T07:39:45.403Z
2020-06-18T08:25:19.090Z
cst1992
<p>Rivers can freeze, but only on the surface. The water still flows below the ice. When it is colder, the ice layer can become thicker.</p>

<p>The kinetic energy of the moving water in rivers delays this freezing. So when water is more calm it freezes more easily.</p>

CC BY-SA 3.0
2016-02-10T19:50:06.157Z
2016-02-11T00:21:31.000Z
2016-02-11T00:21:31.000Z
Santiago
<p>Crystals of sugar form in hot saturated sugar solution as it cools down, due to excess sugar molecules not fitting in the solution and precipitating as crystals.</p>

<p>In a similar situation, if we have a region where temperatures are well below zero, still water should freeze. But in rivers, water doesn't freeze, because it's flowing. Do ice crystals form in such super-cold water?</p>

<p>(P.S. If you know any applicable tags, please add them.)</p>

CC BY-SA 3.0
2016-02-10T07:30:25.880Z
Possible duplicate of [Is it possible for rivers to freeze completely and stop flowing?](http://earthscience.stackexchange.com/questions/4358/is-it-possible-for-rivers-to-freeze-completely-and-stop-flowing)
Fred
CC BY-SA 3.0
2016-02-10T07:37:55.160Z
It's not a duplicate per-se, as the essence of the accepted answer is what I know already. However, I have added a relevant snippet below that answers my question.
cst1992
CC BY-SA 3.0
2016-02-10T19:31:44.327Z
I think your problem may be in the assumption that the river water is "super-cold".  I think that if you stuck a thermometer in a flowing river (or FTM a large lake), it would register 0 C.  Two reasons I can think of.  1) The river water is in contact with high thermal mass ground.  2) If any parcel of water does freeze, it's a) probably on the surface, in contact with colder air, and b) releases some heat by freezing, then floats to the surface.
jamesqf
CC BY-SA 3.0
2018-03-26T02:31:46.630Z
@cst1992 This link is pretty close to an answer.   It's more physics or chemistry than Earth science.    https://phys.org/news/2011-11-supercool-doesnt-.html
userLTK
<water><rivers><ice>
Do ice crystals form in running super-cold water?
cst1992
# Do ice crystals form in running super-cold water?

(Asked by: username_0 on 2016-02-10)

Crystals of sugar form in hot saturated sugar solution as it cools down, due to excess sugar molecules not fitting in the solution and precipitating as crystals.

In a similar situation, if we have a region where temperatures are well below zero, still water should freeze. But in rivers, water doesn't freeze, because it's flowing. Do ice crystals form in such super-cold water?

(P.S. If you know any applicable tags, please add them.)

**Tags:** water, rivers, ice

> **Comments:**
> **username_1**: Possible duplicate of [Is it possible for rivers to freeze completely and stop flowing?](http://earthscience.stackexchange.com/questions/4358/is-it-possible-for-rivers-to-freeze-completely-and-stop-flowing)  
> **username_0**: It's not a duplicate per-se, as the essence of the accepted answer is what I know already. However, I have added a relevant snippet below that answers my question.  
> **username_2**: I think your problem may be in the assumption that the river water is "super-cold".  I think that if you stuck a thermometer in a flowing river (or FTM a large lake), it would register 0 C.  Two reasons I can think of.  1) The river water is in contact with high thermal mass ground.  2) If any parcel of water does freeze, it's a) probably on the surface, in contact with colder air, and b) releases some heat by freezing, then floats to the surface.  
> **username_3**: @username_0 This link is pretty close to an answer.   It's more physics or chemistry than Earth science.    https://phys.org/news/2011-11-supercool-doesnt-.html  

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## 2 answers

### Answer by username_0 on 2016-02-10. Score: 1

A snippet from the linked question:

> username_1 says:
>
> Also, while water is flowing its potential energy is constantly being converted to heat energy that resists freezing on the molecular level and subsequent crystallization.
>
> For flowing water to freeze, the temperature would have to be exceptionally cold


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### Answer by username_4 on 2016-02-10. Score: 1

Rivers can freeze, but only on the surface. The water still flows below the ice. When it is colder, the ice layer can become thicker.

The kinetic energy of the moving water in rivers delays this freezing. So when water is more calm it freezes more easily.


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