What makes dry quicksand so deadly?

Dry quicksand was a mythical substance — normal-looking sand that could swallow you in a flash. That is, until 2004, when scientists made the stuff in a lab. (Mark told you about that development.)

In this video, geologist Matt Kuchta explains how dry quicksand is different from both wet quicksand and stable sand. Hint: Think "Jenga".


    1. You should have made an awesome video of it then, featuring Admiral Akbar  Neither the post nor the video presenter claimed that this represented cutting edge science.

    2. Why do people feel the need to point out that something on the internet isn’t “new”? You do realize that it’s “new” to someone, right?

  1. you can actually find a similar subtance at places where lots of heavy trucks are moving on dirt roads and constuctions sites. Its a beautiful sand that goes pufff when you step on it and retains wonderful shoe or tire marks until its gets blown by the wind..

    1. True, but I don’t think it can swallow you alive.  I don’t think dry quicksand exists in nature, except I think it has been observed during an earthquake.  But if there’s an earthquake, dry quicksand is the least of your worries.

      1. It most definitely exists in nature in at least one place in the world, the Glamis sand dunes in California.

        I’ve been riding out there on my dirtbike on fairly level sand and my front tire just sank and I went over the bars and my bike flipped upside down.  

  2. “A shark and an octopus were typical sea creatures — normal-looking sea creatures that could swallow you in a flash. That is, until 2004, when scientists made the stuff in a lab.”  THIS IS FUN!!!!

  3. You haven’t heard reports of people being swallowed whole by quicksand ? Here’s one then. I have a friend who’s a mountain guide. While backcountry skiing he skied behind a ridge. Some very light snow had accumulated there and he completely fell through. He was wearing an avalanche airbag but didn’t even have time to trigger it. Fortunately his wife was there and dug him up quickly but he’d already fainted from lack of air (it went into his mouth and nostrils). Note that this was not an avalanche as the snow didn’t move.

    1. I don’t quite follow… are you saying there was quicksand under the snow and he was swallowed up by the sand? I’m at least reading it as he was swallowed up by snow, which is a completely different thing. (And if you really are equalling snow and quicksand then I assume you yourself don’t live where there are lots of snow.)

      1.  I think they’re referring to the mechanics of it, it can be a lot like quicksand in the wrong conditions. (see http://abcnews.go.com/US/skier-rescue-woman-survives-trapped-upside-creek-bed/story?id=16052786 ). Don’t think about walking in the snow and having your feet punch through. Think about powder skiing, where your weight is distributed over very long, very wide boards that pack the snow down under you. It’s pretty unusual to have your skis suddenly keep sinking. You get successive layers of snow all packed on top of each other, right? Except sometimes when there’s a lot of fresh powder, say, in a creekbed, especially in a dry winter, some other dynamic comes into play and it’s possible to sink into it like you would in a pool of water, with it compacting down around you like cement after you sink in.

  4. Which reminds me of…

    …Ok, I realize MAD MAX BEYOND THUNDERDOME is not a documentary…

    But there ares two scenes in it of desert sucking “drysand.”  

    First, Max’s donkey gets sucked down in a patch of it.

    Later, the Lost Tribe of kids are attempting to cross the desert, and 1 or 2 kids get sucked down in it (Max manages to save the other ones).

    They’re bizarre scenes, because I’ve never seen anything like it in any movie, ever.       Yes, I’ve seen a million scenes in movies of people going down in wet quicksand (Everything from every other version of THE HOUND OF THE BASKERVILLES to BLAZING SADDLES to INDIANA JONES AND THE CRYSTAL SKULL).

    But this stuff….   what’s the precedent for it?    The people who wrote the movie are actually Australian… is there any precedent for this kind of phenomena in the Australian outback, or any other deep sandy-sand-sand desert?

      1. “Just when you thought it was safe to go back in the water – you can’t get to it.”  Blood Beach, 1980. (Spoiler – it turns out not to be dry quicksand).

      2.  Thanks, I had forgotten this scene.   Although I should have predicted it, because, oddly enough, MAD MAX BEYOND THUNDERDOME has a lot of nods to LAWRENCE OF ARABIA.

  5. I’d like to see him do a demo of glacier silt. There’s reports out there of people getting stuck in it (and dying as the tide came in and drowned them) but I’ve never actually seen the effect. 

    I mean, we’ve all gotten boots stuck in mud and felt suction pull it off our feet, but apparently waterlogged silt is significantly better at it.. it’s sort of like quicksand in that you can walk on it for a little bit, but once you start to sink it clings so tightly it takes a team of people to get you out.
    Closest I’ve ever gotten is throwing rocks in the stuff.. which makes a glorious SPLUT noise when it lands. 

  6. I correctly surmised that it was air separating the fine grains of the dry quicksand that was causing the engulfing effect.  However, prior to the landings of the Surveyor spacecraft on the moon, NASA was concerned that a manned lunar lander could be completely swallowed up by the surface dust on the moon.  Since there was no atmosphere to provide any large gaps between grains, I wonder what they thought would be the mechanism allowing this.  Electrostatic repulsion between grains keeping them widely spaced?  Strange grain shapes?

    1. Consider that the air is not part of the structure. All that’s needed is gaps between the dust particles.

  7. A Myth? You get pockets of this stuff in the Namib desert, you are merrily driving along with your 4X4 and next moment it’s completely sunken into soft sand not dissimilar to this stuff right up to it’s drive shafts. Looks exactly like the sand around it, but when you step on it or try to drive over it, you sink in instantly. Usually not so deep though(luckily), probably 2 feet at most and the pockets aren’t that big, but big enough to get you well and truly stuck.

    You probably get it in any of the other deserts out there as well…

  8. Did bother anyone else that he always seemed to throw things a little harder into the dry quicksand than the wet? I’m sure the effect would have still been impressive.

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