Curious squiggles

On my walk to work this morning, I noticed these odd patterns in the snow and ice over the sidewalk. At first glance, I thought bird tracks or traces of squirrels rushing through the snow…but no, that makes no sense. They are variable in size and length and follow short meandering pathways, like this:

What’s your explanation? I don’t think it’s Cthulhu cultists leaving ritual markings around my house. My tentative explanation is that it’s an effect of salt — that we scatter salt on our sidewalk, which then generates the meandering scribbles as the sun rises and the warmth causes differential melt patterns in response to the local salt concentration.

Alternatively, I did initially try reading the markings. I couldn’t make sense of them, but maybe if I try harder the meaning will emerg…ph’nglui mglw’nafh Cthulhu R’lyeh wgah’nagl fhtagn. Iä! Iä!


  1. charley says

    I don’t think scattered salt particles would travel such a wiggly path. Are the marks localized or widespread? Bird excrement falling from above?

  2. robro says

    I was going to say “Ice Worms” but I see chigau beat me to it. But here’s a different thought, plant matter or other organics on the sidewalk? Just spit-balling ideas as they say in my business sometimes.

  3. Jazzlet says

    Could it be something that was there before the snow, like slug trails? They tend to be wiggly, and not continuous.

  4. says

    They’re everywhere along the driveway and our sidewalk, but are not present on the neighbor’s walk or where the path continues to the university. My wife had scattered salt along our driveway/sidewalk about an hour before I went out, which is why the salt hypothesis is my favorite.

    I have no idea (other than randomness) why there should be so much variation in their path.

  5. says

    Hard to tell without a scale and knowing whether or not this is flat. Also wouldn’t hurt to know what kind of snow it is e.g., new dusting, windblown, several days old which has gone through a warming/cooling cycle, etc.) I’m guessing that the longest ones are only a few inches, but if they’re feet long, I’ve seen mole tracks like that, although never with that variation in width. If they’re inches, then I’d guess it’s salt that was scattered from the side, especially if the surface is not level.

    I suggest looking at the very ends of the tracks. Small pebbles find their way into road salt sometimes.

  6. says

    Oh, and if it’s still well below freezing, the salt is unlikely to have completely melted yet. Which also reminds me, was it standard salt or calcium?

  7. numerobis says

    Clearly panspermia; those must be worms from Mars, which explains why they survived the trip and are active in your relatively balmy weather. There can be no other explanation.

    (As for spreading salt: it’s far better to spread small gravel or sand. They’ll melt ice pretty well when the sun comes out, they’ll provide friction, and they won’t poison plants.)

  8. flex says

    Possibly denser snow falling off tree branches above?

    I think there is a hint of scale in the photo. If I’m not mistaken, on the middle of the left side is the imprint of a salt-encrusted tire track, and there is a divot in the asphalt about a fifth of the way up the left hand edge. Around that divot and a bit higher up you can see salt crystals. Those crystals about the same width as the traces, so trickling salt-induced snow melt could well be the cause.

  9. bcw bcw says

    I would guess as lump of salt slowly dissolves and mixes with the low-availability water (since the temperature is low,) one side of the salt chunks melts first and the lump rolls onto its side, exposing a different side of the salt chunk to water/ice. When it rolls, it moves the back side away from the available ice while moving the side in the propelled direction into contact with more ice. This mean the path tends to go in one direction but with a lot of randomness from shape and ice thickness variations. If you put salt onto a block of ice it etches a tunnel down into the ice, but in that case gravity dominates. There is still probably a gravity component which means if the sidewalk is tipped the alt may all tend to move downhill.

    That’s my theory and I’m sticking to it.

  10. Richard Smith says

    Can salt crystals “walk” while interacting with snow? Maybe a tiny version of the sailing stones…

  11. astringer says

    I’d agree with the ‘walking crystal’ idea: the trails appear to narrow with distance (as would be case if crystal was dissolving as it went), and a few of the close ups look like starter versions, such as shown here (annoying “sign in” window, but relevant images can be seen).

    Suggest PZ send image to CRREL: your taxes fund it…

  12. birgerjohansson says

    A very small version of crop circles, created by smaller relatives of the critters that gave Mel Gibson’s family a bad time.

  13. charley says

    Looks like tomorrow is another cold day in Morris. Have Mary toss some more salt at the same time of day or temp in a fresh area and watch what happens.

  14. Reginald Selkirk says

    Time lapse video would make for the most pleasing result, but I think it would lead to another experiment on the effect of cold temperatures on camera batteries.

  15. wzrd1 says

    The mailman sneezed?
    Space alien drones retrieving snow samples to make snow cones?
    Mammoth flatus?

  16. bcw bcw says

    @26 ice worms seem really cool, presumably all the lipids in their bodies have really short chain lengths/molecular weights so the lipids are at the same in-plane semi-liquid, out -of-plane solid that human cell membranes have. Perhaps also many fewer hydrogen bond sites to allow DNA & proteins to bond and unbond as needed? SO we get a fever at 105F (40C) and die cocked egg at 110F (57C) or so while they bake at 41F (5C.) The ratio of “dead” to “normal” is about 1.02 in kelvin for both humans and worms. So a 2% range in allowed internal temperature for both.

  17. bcw bcw says

    Very cool. Ice Worms have modified ATP with greater e mobility:

    The segmented annelid worm, Mesenchytraeus solifugus, is a permanent resident of temperate, maritime glaciers in the Pacific northwestern region of North America, displaying atypically high intracellular ATP levels which have been linked to its unusual ability to thrive in hydrated glacier ice. We have shown previously that ice worms contain a highly basic, carboxy terminal extension on their ATP6 regulatory subunit, likely acquired by horizontal gene transfer from a microbial dietary source. Here we examine the full complement of F1F0 ATP synthase structural subunits with attention to non-conservative, ice worm-specific structural modifications. Our genomics analyses and molecular models identify putative proton shuttling domains on either side of the F0 hemichannel, which predictably function to enhance proton flow across the mitochondrial membrane. Other components of the ice worm ATP synthase complex have remained largely unchanged in the context of Metazoan evolution

  18. lochaber says

    I think it’s the salt crystals. I feel like I’ve seen similar patterns before, but can’t remember specifically where.

    the paths look too short, too frequent, and lacking interconnection to be something biological.

    My best guess right now, is that the salt is melting the ice and dissolving into the water, and there is a concentration gradient that ends up pushing (pulling?) the salt crystal along.

    I would think it might be easy to set up a verification experiment, but these sort of things can be deceptively difficult. maybe freeze some water on a plate, and drop a salt crystal on it, check periodically?

  19. nomdeplume says

    @21 Agreed. They look something like the features on Mars where water has flowed down slopes.

    When I first saw the photo I was thinking slugs or earthworms, which leave similar trails around here after rain or condensation, but the discontinuous nature doesn’t fit, nor the temperstures.

  20. John Morales says

    It remains unknown whether or not PZ made any further investigation in situ.

    Most of us monkey-brain types would at the very least poke it with a stick.

    (Still… “Always Leave Them Wanting More”)

  21. wzrd1 says

    @ 29, most likely, to be serious. Lower concentration gradient forward, higher behind pushing, add a tad of wind, get entertaining paths.
    As was mentioned in @ 30, discontinuous paths pretty much eliminate biological sources.

    John, the problem with poking things with sticks is, some things will poke back.