Learn How to Escape Quicksand

What Is Quicksand?

Quicksand is a mixture of two phases of matter that pack together to produce a surface that looks solid but collapses from weight or vibration. It can be a mixture of sand and water, silt and water, clay and water, sediment and water, or even sand and air. The solid component accounts for most of the mass, but there are larger spaces between particles than you'd find in dry sand. The interesting mechanical properties of quicksand are bad news for the unwary jogger but are also why sand castles hold their shape.

Where Can You Find Quicksand?

You can find quicksand all over the world when the conditions are right. It's most common near the coast, in marshes, or along riverbanks. Quicksand can form in standing water when saturated sand is agitated or when soil is exposed to upward-flowing water (e.g., from an artesian spring).

Dry quicksand can occur in deserts and has been reproduced under laboratory conditions. Scientists believe this type of quicksand forms when very fine sand forms a sedimentation layer over more granular sand. Dry quicksand was considered a potential danger during the Apollo missions. It may exist on the Moon and Mars.

Quicksand also accompanies earthquakes. The vibration and resulting solid flow have been known to engulf people, cars, and buildings.

How Quicksand Works

Technically speaking, quicksand is a non-Newtonian fluid. What this means it can change its ability to flow (viscosity) in response to stress. Undisturbed quicksand appears solid, but it's really a gel. Stepping on it initially lowers the viscosity, so you sink. If you stop after the first step, the sand particles beneath you get compressed by your weight. The sand around you also settles into place.

Continued movement (like thrashing around from panic) keeps the mixture more like a liquid, so you sink further. However, the average human has a density of about 1 gram per milliliter, while the average quicksand density is about 2 grams per milliliter. You'll only sink halfway, no matter how badly you freak out.

Disturbing quicksand makes it flow like a liquid, but gravity acts against you. The trick to escaping the trap is to move slowly and try to float. Strong forces stiffen quicksand, making it more like a solid than a liquid, so pulling and jerking only make a bad situation worse.

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About Sand

By Andrew Alden

How Quicksand Can Kill You

A quick Google search reveals most writers don't have personal experience with quicksand or consult water rescue experts. Quicksand can kill!

It's true you don't sink in quicksand until you're submerged. Humans and animals typically float in water, so if you are standing upright, the furthest you'll sink in the quicksand is waist-deep. If the quicksand is near a river or coastal area, you can still drown the old-fashioned way when the tide comes in, but you won't suffocate with a mouthful of sand or mud.

So, how do you die?

• Drowning: This happens when additional water moves in over the quicksand. It could be the tide, splashing water (since quicksand can occur underwater), heavy rain, or falling over into water.
• Hypothermia: You can't maintain your body temperature forever when half of you is encased in sand. Hypothermia occurs rapidly in wet quicksand, or you can die in the desert when the sun goes down.
• Suffocation: Depending on how you are positioned in quicksand, your breathing could be impaired. While you aren't going to sink up to your chest standing upright, falling into quicksand or failing at a self-rescue attempt could end badly.
• Crush Syndrome: Extended pressure on skeletal muscle (like your legs) and the circulatory system wreaks havoc on the body. Compression damages muscles and nerves, releasing compounds that cause kidney damage. After 15 minutes of compression, rescuers have to apply special techniques to prevent loss of limbs and sometimes life.
• Dehydration: If you're trapped, you may die of thirst.
• Predators: Those vultures watching from the trees may decide to snack on you once you stop struggling if the alligator doesn't get you first.

Dry quicksand presents its own special risks. There are reports of people, vehicles, and entire caravans sinking into it and being lost. Whether this has actually occurred is unknown, but modern science considers it possible.

How to Escape From Quicksand

In the movies, escape from quicksand often comes in the form of an outstretched hand, underwater vine, or overhanging branch. The truth is, pulling a person (even yourself) out of quicksand won't result in freedom. Removing just your foot from quicksand at the rate of 0.01 meters per second requires the same force required to lift a car. The harder you pull on a branch or a rescuer pulls on you, the worse it gets!

Quicksand is no joke and self-rescue isn't always possible. National Geographic made a fantastic video entitled "Can You Survive Quicksand?" which basically shows how the Coast Guard can save you.

If you step into quicksand, you should:

1. Stop! Immediately freeze. If you are with a friend who is on solid ground or you can reach a branch, reach out and put as much weight on them/it as possible. Making yourself lighter makes it easier to escape. Slowly float out. The best way to do this is to try to increase your surface area by leaning back into the quicksand and slowly moving your legs to liquefy the water around them. Don't kick wildly. If you're very close to solid land, sit down on it and slowly work your feet or lower legs free.
2. Don't panic. Wriggle your feet while leaning back to increase your surface area. Try to float. If there is an incoming tide, you may be able to use your hands to mix in more water and clear some of the sand. 
3. Call for help. You're in too deep or out too far for help. Keep an eye out for people who can call for help or take out your cell phone and call yourself. If you live in a quicksand-prone area, you know to keep a charged phone on your person for just such an emergency. Stay still and wait for help to arrive.

Make Homemade Quicksand

You don't need to visit a riverbank, beach, or desert to explore the properties of quicksand. It's easy to make a homemade simulant using cornstarch and water. Just mix:

• 1 cup water
• 1.5 to 2 cups cornstarch
• Food coloring (optional)

If you're brave, you can expand the recipe to fill a kiddie pool. It's easy to sink into the mixture. It's nearly impossible to suddenly pull free, but slow movements allow time for the fluid to flow!

Sources

• Bakalar, Nicholas (September 28, 2005). "Quicksand Science: Why It Traps, How to Escape". National Geographic News. Retrieved October 9, 2011.
• Jayra Narin. "Quicksand horror death of mother, 33, who drowned after getting trapped as the tide came in while on holiday in Antigua." DailyMail.com. August 2, 2012.
• Kelsey Bradshaw. "How a Texas man was killed by quicksand on the San Antonio River last year." mySanAntonio.com. September 21, 2016.
• Khaldoun, A., E. Eiser, G. H. Wegdam, and Daniel Bonn. 2005. "Rheology: Liquefaction of quicksand under stress." Nature 437 (29 Sept.): 635.
• Lohse, Detlef; Rauhé, Remco; Bergmann, Raymond & van der Meer, Devaraj (2004), "Creating a dry variety of quicksand", Nature, 432 (7018): 689–690.