<p>I live near a river in the Pacific NW (USA) and it has been cold (low teens °F, around -10°C) for over a week. The river is about 5-6 feet (1.5–1.8 metre) deep and moving fast enough so the river at the surface is completely ice free. The bottom of the river has ice attached to the rocks and occasionally the ice pops off and floats to the surface. This seems to indicate that either the rocks are below freezing or the water is supercooled and forms ice at the rock because the speed of the water at the rock surface is slower.</p>
<p>Has there been an analysis of this phenomenon?</p>

CC BY-SA 4.0
2024-01-16T02:02:28.753Z
its called anchor ice. https://en.wikipedia.org/wiki/Anchor_ice and should have popped up if you tried googling "ice at the bottom of stream".
John
CC BY-SA 4.0
2024-01-16T02:09:13.067Z
@John Thanks. It didn't occur to me to Google that phrase.
Stevan V. Saban
CC BY-SA 4.0
2024-01-16T09:23:42.073Z
@John so is the reason it forms at the bottom because the turbulent mixing higher up prevents it from remaining frozen??
JeopardyTempest
CC BY-SA 4.0
2024-01-16T18:12:20.307Z
@JeopardyTempest Frazil ice formation seems to be the important step: https://en.wikipedia.org/wiki/Frazil_ice#:~:text=Ice%20generally%20floats%2C%20but%20due,to%20the%20bottom%20very%20easily.
Stevan V. Saban
<rivers><thermodynamics>
Ice on rocks at bottom of flowing river
Stevan V. Saban
# Ice on rocks at bottom of flowing river

(Asked by: username_0 on 2024-01-15)

I live near a river in the Pacific NW (USA) and it has been cold (low teens °F, around -10°C) for over a week. The river is about 5-6 feet (1.5–1.8 metre) deep and moving fast enough so the river at the surface is completely ice free. The bottom of the river has ice attached to the rocks and occasionally the ice pops off and floats to the surface. This seems to indicate that either the rocks are below freezing or the water is supercooled and forms ice at the rock because the speed of the water at the rock surface is slower.

Has there been an analysis of this phenomenon?

**Tags:** rivers, thermodynamics

> **Comments:**
> **username_1**: its called anchor ice. https://en.wikipedia.org/wiki/Anchor_ice and should have popped up if you tried googling "ice at the bottom of stream".  
> **username_0**: @username_1 Thanks. It didn't occur to me to Google that phrase.  
> **username_2**: @username_1 so is the reason it forms at the bottom because the turbulent mixing higher up prevents it from remaining frozen??  
> **username_0**: @username_2 Frazil ice formation seems to be the important step: https://en.wikipedia.org/wiki/Frazil_ice#:~:text=Ice%20generally%20floats%2C%20but%20due,to%20the%20bottom%20very%20easily.  

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## 0 answers

