In the rare instance where quicksand is deep enough that a person could become submerged in it, one would have to try pretty hard to go under. The same vacuum effect is what causes certain consistencies of mud to pull the shoes off of your feet. When limbs are moved around under the surface, the movement creates a vacuum pressure, greatly increasing the amount of effort necessary to move. Exhaustion is the biggest risk, considering the amount of energy it can take to untangle oneself from the waterlogged soil. In reality, quicksand is very rarely more than a few feet deep, making it more of a messy nuisance than a life-threatening hazard. Because the water seeps in from the bottom, the top layer of sand is often dry, causing it to appear to be normal sand. This significantly reduces the friction between the grains of sand, compromising its ability to support weight. But once there is sufficient moisture, the sand and water becomes a suspension where the sand particles are floating within the water. Normal sand can support extreme amounts of weight because friction between the grains of sand creates a force chain, distributing the load across a large area.
Traditional quicksand is created when water seeps up from an underground source and saturates an area of sand, silt, clay, or any other grainy soil.
Unsurprisingly, real quicksand is pretty tame in comparison to Hollywood’s depiction, but traditional quicksand does have an evil cousin that would pose a grave threat to anyone who might stumble upon it… if it exists. Barring any nearby vines or branch-wielding comrades, the victim will slowly sink until completely submerged. It is usually represented as a deep pool of sandy goo which blends in with its surroundings, lying in wait to slowly suck in anyone who attempts to traverse it. Quicksand is one of the staple environmental hazards in cartoonish low-budget movies, where it has been known to quickly swallow unwitting persons as they wander through jungles and deserts. If you’re not careful, you could lose your life. Next time you’re traipsing around in a wet, sandy, unfamiliar area, you had best be on your guard for the exotic material known as quicksand.