<p>What you are looking at is called <a href="https://en.wikipedia.org/wiki/Hair_ice" rel="noreferrer">hair ice</a>.  The Wikipedia article seems a little unclear on the cause, but it seems associated with dead plant material, and the presence of certain fungi.</p>
<blockquote>
<p>Hair ice forms on moist, rotting wood from broadleaf trees when
temperatures are slightly under 0 °C (32 °F) and the air is humid.[1]
The hairs appear to root at the mouth of wood rays (never on the
bark), and their thickness is similar to the diameter of the wood ray
channels.[1] A piece of wood that produces hair ice once may continue
to produce it over several years.[1]</p>
</blockquote>
<p>More information provided in comments by @trond hansen can be found in another article on Hair Ice at the <a href="https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/frost-and-ice/hair-ice" rel="noreferrer">UKs' Met Office</a></p>

CC BY-SA 4.0
2022-11-19T05:22:50.373Z
here is a bit more information and a video of hair ice forming https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/frost-and-ice/hair-ice
trond hansen
CC BY-SA 4.0
2022-11-18T22:48:42.923Z
2022-11-19T22:29:21.330Z
2022-11-19T22:29:21.330Z
justCal
<p>Last night it dropped to around 25°F here in Wildwood, GA.  I noticed what looked like patches of cotton on the ground that were not there the day before.  At closer look they are patches of frost/ice.  Some, like the image below, appear as if they were spun on a machine.</p>
<p>How do these patterns form?</p>
<p><a href="https://i.sstatic.net/EiGJC.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/EiGJC.jpg" alt="enter image description here" /></a></p>
<p>Below is another one (photo taken 11-20-2022).</p>
<p><a href="https://i.sstatic.net/se3On.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/se3On.jpg" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2022-11-18T14:24:59.553Z
It looks a bit like an [ice spike](https://en.wikipedia.org/wiki/Ice_spike), some of which take on a very non-spike-like form.
David Hammen
CC BY-SA 4.0
2022-11-18T19:14:24.470Z
Thank you @DavidHammen, it did not look like ice at all.  Then, when I picked one up it disintegrated as it is a very fragile ice formation.  It is quite amazing to me.
relayman357
CC BY-SA 4.0
2022-11-20T03:18:50.260Z
So... meteorologist here... and I've never seen such a thing!!! Was sure it look fake! But justCal's answer seems legitimate, amazing! Have seen hoar frost and such, but that's amazing stuff. Of course living in FL most of my life... helps aid my lack of familiarity. I would think just the right wind is key too. Was it all over the yard, or only in certain areas? And did you notice if there was any light wind in the morning? And the direction? A nearby body of water?
JeopardyTempest
CC BY-SA 4.0
2022-11-20T03:18:55.983Z
Just questions that may help be of extra interest in light of justCal's great answer and trond's great link!  Proof we all still have much to learn in life!
JeopardyTempest
CC BY-SA 4.0
2022-11-20T18:37:43.670Z
Hi @JeopardyTempest, they were in patches on edge of woods and along gravel road.  Don't recall the wind conditions, but i would expect little or no wind as these things are delicate.  No body of water nearby.
relayman357
<ice>
Formation of ice shape
relayman357
# Formation of ice shape

(Asked by: username_0 on 2022-11-18)

Last night it dropped to around 25°F here in Wildwood, GA. I noticed what looked like patches of cotton on the ground that were not there the day before. At closer look they are patches of frost/ice. Some, like the image below, appear as if they were spun on a machine.

How do these patterns form?

[![enter image description here](https://i.sstatic.net/EiGJC.jpg)](https://i.sstatic.net/EiGJC.jpg)

Below is another one (photo taken 11-20-2022).

[![enter image description here](https://i.sstatic.net/se3On.jpg)](https://i.sstatic.net/se3On.jpg)

**Tags:** ice

> **Comments:**
> **username_1**: It looks a bit like an [ice spike](https://en.wikipedia.org/wiki/Ice_spike), some of which take on a very non-spike-like form.  
> **username_0**: Thank you @username_1, it did not look like ice at all.  Then, when I picked one up it disintegrated as it is a very fragile ice formation.  It is quite amazing to me.  
> **username_2**: So... meteorologist here... and I've never seen such a thing!!! Was sure it look fake! But username_3's answer seems legitimate, amazing! Have seen hoar frost and such, but that's amazing stuff. Of course living in FL most of my life... helps aid my lack of familiarity. I would think just the right wind is key too. Was it all over the yard, or only in certain areas? And did you notice if there was any light wind in the morning? And the direction? A nearby body of water?  
> **username_2**: Just questions that may help be of extra interest in light of username_3's great answer and username_4's great link!  Proof we all still have much to learn in life!  
> **username_0**: Hi @username_2, they were in patches on edge of woods and along gravel road.  Don't recall the wind conditions, but i would expect little or no wind as these things are delicate.  No body of water nearby.  

---

## 1 answers

### Answer by username_3 on 2022-11-18. Score: 10 | Accepted answer

What you are looking at is called [hair ice](https://en.wikipedia.org/wiki/Hair_ice). The Wikipedia article seems a little unclear on the cause, but it seems associated with dead plant material, and the presence of certain fungi.

> Hair ice forms on moist, rotting wood from broadleaf trees when
> temperatures are slightly under 0 °C (32 °F) and the air is humid.[1]
> The hairs appear to root at the mouth of wood rays (never on the
> bark), and their thickness is similar to the diameter of the wood ray
> channels.[1] A piece of wood that produces hair ice once may continue
> to produce it over several years.[1]

More information provided in comments by @username_4 can be found in another article on Hair Ice at the [UKs' Met Office](https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/frost-and-ice/hair-ice)

> **Comments:**
> **username_4**: here is a bit more information and a video of hair ice forming https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/frost-and-ice/hair-ice  

---

