Sand dunes.
These breathtaking, gigantic structures
formed by tiny grains of sand
are beautiful
until you're being swallowed by one.
Deserts are dangerous.
If you don’t watch your step,
you could end up buried alive.
A dune is a mound of sand
formed when the wind blows grains
of sand into a sheltered area.
Dunes have a slip face,
the side that's sheltered from the wind,
and a windward side
where the wind pushes material.
When the slope becomes greater
than 34 degrees,
gravity pulls the loose sand down,
causing slumping.
"We have to get out of here"
Sand dunes are marketed
as tourist destinations.
But sand is an unstable substance
that can collapse quickly
without any warning,
swallowing people in seconds.
Nothing says your vacation is over
like being trapped in a dune
that's 0.5 km (0.3 mi) high,
huh?
The biggest dunes can have nearly
5 billion m² (169.5 billion ft²) of sand.
If you find yourself trapped inside a dune,
try to stay quiet and calm.
Every orifice of your body
will be bombarded by grains of sand.
“Sand in my eyes!”
And breathing heavily or screaming
will help sand enter your lungs faster,
which is painful and dangerous.
Mount Baldy, in Indiana, is 38 m (125 ft) high.
In 2013, this huge sand dune
swallowed a six-year-old.
The boy fell 3.3 m (11 ft) into the sand
and remained buried
for more than three hours.
He only survived
because an air pocket formed around
him as the sand was collapsing.
Even if you’re as lucky as Nathan
and have air to breathe,
you’ll need to preserve it.
Don’t do anything that would
use up your oxygen supply quickly,
like making intense movements.
Sand dunes are found
in deserts and on beaches,
and they’re different.
“Sand in the eye!”
Dunes near the ocean are stationary
since the water cements them in place.
But in a desert,
the dunes travel with the wind,
which presents another threat.
Wind-blown sand
can cause blindness and disorientation.
And a dune’s nature is hazardous enough
with your two eyes working.
If you want to preserve them,
you’ll need to keep your eyes closed.
This might sound counterintuitive.
But if the sand is fresh,
it will fill back in
wherever you push it away.
If you try digging yourself out,
you could end up buried even further
down inside the dune.
Some animals can live inside dunes.
The sandfish, a type of lizard,
can retract its legs
and move through the sand.
A few species thrive in this environment,
but you’re not one of them.
If a dune swallows you,
it would be tough to find you quickly
if people don’t know your location.
“Get me out of here!”
Always tell people exactly
where you're going,
so they can send help if you don't return.
So, you found a way to survive
a collapsing sand dune.
But, what about other types of sand?
“Quicksand!”
Could you survive quicksand?
Find out here on How to Survive.