Mysteries of the Snow Rose

[corvi]

We have received our once-a-year pile of snow, which means I will soon be making my once-a-year post containing a pile of snow photos.

This year, the snow is doing something I haven't seen before: as it melts, raised shapes that look kind of like frosting roses on a cake appear. They're only in the forest, not on open ground, so I think they probably have something to do with snow falling off trees and getting compressed, then melting more slowly than the regular ground snow, but it's cool and weird.



There are literally hundreds of them. Has anyone seen these before? What are they called? How do they form?



Hmmmm.

Option 1
They form when snow gets a little slushy and falls off trees. Multiple clumps fall out of the tree, first larger ones, then smaller ones. Each clump flattens into a disc when it hits the snow already on the ground. Subsequent smaller clumps falling from the same branch land on top of previous discs and make a set of concentric layers.

Problem: I think these appeared the day after all the snow fell off the trees.


Option 2
They form when a stalactite of partially-melted snow, cone shaped, falls from a tree and imbeds itself in the fluffier snow on the ground. When, the next day, the ground snow melts, remnants of the cone collapse into a set of raised concentric arcs.

Problem: I don't know if there's any reason to assume the snow chunks falling off the trees fall in cone shapes.

Option 3
They're caused by melted, liquid water dripping from trees, and slushing up the snow on the ground with splashes.

Problem: I would expect them to last less long than the rest of the snow, if they're made by liquid. But they're outlasting the rest of the snow and it looks like we could end this years Snow Dump by just having little rose shapes scattered around the ground, long after everything else has melted.

---

Baffled and delighted by the snow roses.

Comments

[ivy]

Possible information: when snow is compressed, it tends to turn into ice, and that lasts longer. (I know this because in some weathers, footprints on snow make an ice footprint impression, and then the snow can melt and you're left with these baffling ice footprints on nothing as the last thing to go.) So if your snow lasts more than one day, or you have freeze/warm/freeze cycles after a compression, perhaps that's relevant? I don't know how MUCH compression you need to get the ice result -- any human walking on them will do it, but I'm unsure about just falling snow.

[grayswandir]

I have no theories whatsoever, but am totally fascinated by your snow roses.

[elinox]

Clearly they're from the fairies. :D

[corvi]

That seems as plausible as any of my theories!

[corvi]

Thanks! I appreciate the Expert Confirmation of my vague intuitions about snow.

Also, darn: you were the person I thought was most likely to have seen this before and know exactly how it happened.

[yam]

I think you should write with your question to the National Snow and Ice Data Center, an organization I am charmed to find out is a thing that exists.

[citrakayah]

I got nothing, but those are really neat.