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What a coincidence! During the hard freeze on New Year's Eve here in Austin, TX, I discovered a field of this stuff in my back yard. When I first saw it, I didn't even recognize it as ice! It looked more like a fungus at first, and only after touching it and seeing that it was dissolving did I realize what it was. After some Googling, I came across this exact Wikipedia article (thanks Wikipedia!).

Here's a photo album of it: https://photos.app.goo.gl/EZ74yJaMZX8VuoEp7

My favorite examples: https://photos.app.goo.gl/JX1f8uhrvnj4k6EY9 https://photos.app.goo.gl/ADD2cojZoEvvRBjH8

Your location (address photos were taken) and full name are visible from the link you shared.
Ah, dang. Didn't think of that. Dang technology. I appreciate you letting me know. I'll see if I can figure out a more anonymous way to share them.
Is that any different than picking a random person from a phone book
> When I first saw it, I didn't even recognize it as ice! It looked more like a fungus at first, and only after touching it and seeing that it was dissolving did I realize what it was.

You weren't too far off:

> In 2015, the fungus Exidiopsis effusa was identified as key to the formation of hair ice.

Did it feel like normal ice?
It feels more like snow, if I remember correctly, but it's been some time since I last had hair ice in my hands.
Worth checking out the main source of that article for more details and pictures: https://boris.unibe.ch/75002/1/bg-12-4261-2015.pdf
I skimmed the paper wondering if there could be some fitness benefit for the fungus. Unless I missed it, they don't suggest any. Anyone have a guess?
That's a very good question. A couple of wild ideas:

- They state there is a "significant ammonium concentration" in hair ice. Ammonium is a frequent byproduct of metabolism, that becomes potentially harmful if concentrations become too high. Maybe hair ice allows the fungus to get rid of ammonium. (I'm extrapolating this from my knowledge of animal cell metabolism, where getting rid of ammonium is a recurring theme. I might be wrong on how well it applies to fungi.)

- Hair ice also seems like it has the perfect shape to prevent the formation of solid sheet ice on top of the deadwood. No sheet ice -> better ventilation.

- I also like sibling's theory of using it a means of dispersal, but the paper makes no mention of hair ice containing any fungus/spores at all.

I wonder if the ice might help protect against extreme low temperatures? Fur on animals traps air, acting as an insulator, so it might be similar here. As the fungus (presumably) provides negligible heat output, it would probably only protect against temporary cold flashes, rather than sustained lows - perhaps unusually cold nights?
I could also be fitness for en environment the fungus is no longer in, or it provides/provided something for neighboring plant of insect life.

It could also just be a random trait; something that's not beneficial or harmful and just happens to survive.

maybe the hairs promote the spread of the fungus. When the hairs are disturbed by the environment/animals the fungus is transported away from the initial site.
Since that server is very slow in USA, here's a mirror: https://www.docdroid.net/i1zITmK/evidence-for-biological-sha...
"Hair Ice" sounds flat and un-poetic, like Donald Trump named it.

"Frost Beard" is the OBVIOUSLY superior name of this phenomenon.

I nominate "Winter's Whiskers".
We have similar stuff growing out of geothermal ground where I worked on Mt Erebus, and we called it "angel's pubes".
sigh as a non US citizen could we please have less mentions of US politics and US political figures on HN? I don't know about others but the extreme US centric nature of HN is wearing me down. When I go on Reddit I go to /r/worldnews specifically to get away from US only news content but even then every second article concerns the Trump administration and its foreign policy.

How in all that is holy can you connect a bio-meteorological phenomenon to the Donald? When people say we are living in dark times I have to concur, public discourse is being destroyed with partisan and identity politics.

Also, not a supporter, but I think his rhetorical flourishes are quite arresting and quirky at times.

Canadian aftershave is probably the better name for the facial hair variant.
Even in a thread about ice forming on trees, someone manages to bring up Trump. Amazing.
It's interesting how lifeforms can mold materials into shapes and states we'd otherwise never think of, or that maybe would even be impossible to produce. The strong silk some spiders make is another example.

Leads me to think that there are a lot of undiscovered properties of materials that could potentially be unlocked by engineering different life forms. We're pretty far from exploring all the possibilities in manufacturing techniques.

This is related to another burning question I have (maybe someone knows): why aren't more resources, students, professionals focused on material sciences?

I have friends in AI, biotech, clean tech, web/apps, robotics, but none in material sciences. And yet materials are so important technologically that we name ages after them (Stone Age, Iron Age, Bronze Age). I lived in "Silicon Valley" even — our industries and progress are so tied to materials, why isn't there more of a focus on material science?

Sometimes I find myself in a state of mind that is more commonly achieved by other people with drugs, where contemplating something mundane in a new way amazes me.

One example is I was thinking about path dependence in manufacturing or growing things. If you take a large handful of dry spaghetti, you can break it fairly consistently in half. But if you cook it first, there is no way to split all the strands in half any more.

i love seeing wikipedia articles making it to the front page. no opinions, just a cool wiki article that probably most people have never heard of.
Me too! I love these random chunks of knowledge floating by...
Yep - this is one of the main reasons I first gravitated to HN about 8 years ago
If I wanted to click 'random' on wikipedia, I can do it myself.

I don't browse HN for this garbage.

Less strange but in my experience even rarer is to have a frozen lake grow bushes of ice crystals like in the first picture here: https://en.m.wikipedia.org/wiki/Ice_crystals
Apparently this can happen in the Washinton area:

https://www.youtube.com/watch?v=MIOGeVPlbWM

I can report that it does. I've seen this hiking in Snohomish County, WA. Hair ice looks a bit like cotton fluff, like something splitting out of a seed pod. It looks like it is growing out of the pieces of wood or bark. The ice crushes like a lightly packed snowball.

Of course this means you have to go hiking in the cold. Totally worth it.

Huh. I wonder if it's the same fungus, or if there are other fungi that have evolved the same trait.
The original 1918 theory confirmed in 2015.

My mind usually defaults to "most things have already been discovered AND confirmed", seeing something like this confirmed only so recently is always cool, as it forces me to rethink some of my assumptions!

(Yes, I know there are plenty of undiscovered, and even more unconfirmed things out there, that doesn't change my mind's default reaction though!)

We got good models for pretty good chunk of phenomena of scales from subatomic to galaxy wide and beyond. Astonishing is the fact that same laws give good predictions on both ends of the scale. I think that's the reason behind the assumption we have most figured out.

But in the middle happens most what we cannot comprehend. How does a cell know when to divide. How exactly the process goes. Why do we have consciousness? Having theories capable of describing atoms and stars we can't figure out the middle, this is fascinating.

Imho the issue is the complexity of system. Stars and atoms are actually not that far apart. In the middle the amount of effects with comparable magnitude and stable states are the greatest.

Maybe this is worth updating on wikipedia.

They didnt know that around freezing you have equilibrium that is both melting and freezing.

As you leave that the equilibrium shifts to freezing only.

Thinking that each of those fibers from the moss start the strand and the ice grows as a result.

EDIT: Chem engineer here, not sure what to cite on something like this, or even the proper language.

This sounds like statistical mechanics thinking to me. At the macro-level, water that is at freezing temperature but that has not frozen yet will appear liquid. However, what's happening at the micro level in the fluid is that small pockets of the water are switching back and forth from frozen to liquid as their bonds tighten up from loss of thermal energy. There's still enough energy in regions of the liquid mass such that these isolated crystals may not be crystals for very long, because the thermal energy transfers from hotter to colder regions, but because the whole mass is bleeding energy into an external system it will eventually reach a tipping point where larger crystals can persist for longer, until eventually the water turns into ice.
You can put your idea on the Talk page, or just put it in. You'll probably want a source that relates to ice formation (a source relating it to this specific phenomenon would be better .. or this might be brought up in one of the existing sources and you can re-use it).
I saw either this or needle ice while hiking in North Carolina in winter of 2016. I couldn't figure out what to Google at the time. It made an extremely satisfying sound to step on (there was tons of it so I didn't feel bad).
How Hair Ice grows: https://www.youtube.com/watch?v=uZ_RJ1z22Vw
Pleasantly surprised, I thought clicking through would lead to something much grosser.
Yeah, I kept reading it as "Hair lice". Glad to have been mistaken.
Reminds me of Storm's hair from Xmen https://img.cinemablend.com/quill/a/2/6/f/7/d/a26f7da9ff28d2...
You need to dig pretty deep in chemistry to find a molecule with a range of properties stranger than H2O.
I see this all the time doing winter hiking in Harriman State Park in NY.
Well obviously, harri man...
Pretty neat any real world applications? I would suspect cryogenics might be a pretty good contender considering that the control of ice-crystal formation is pretty important for preserving tissue. The recrystallisation inhibitor properties of what ever proteins are involved in this seems to be just what is needed as they prevent small ice-crystals from forming larger ones and the large crystals are the problem as they burst tissue.
I wonder if hair ice would be better, or worse, on an aircraft wing. I think it can't be structurally stronger, so it should get knocked or blown off easier, but I'm only about 60% more confident. A better deicer solution would be an interesting market disruption.
Somewhere there's a commercial application or two for this waiting to be discovered.
Stuff of legends. I wonder if there are any local tales about trees with beards?
Tolkien wrote Treebeard in LOTR. Grey beard could be this?

"a large Man-like figure, at least fourteen foot high, very sturdy, with a tall head, and hardly any neck. Whether it was clad in stuff like green and grey bark, or whether that was its hide, was difficult to say. Arms, at a short distance from the trunk, were not wrinkled, but covered with a brown smooth skin. The large feet had seven toes each. Grey beard, deep brown eyes, shot with a green light"