What was that shaking you felt?
Was it an earthquake?
As you rush out of your house,
you see a giant mass of mud
heading your way,
and it’s swallowing trees, cars,
and everything in its path.
It even took an entire house away.
What could it do to you?
Mudslides occur at the bottom
of slopes or canyons.
Heavy rainfall, and natural disasters
like floods and hurricanes
that cause surges in water,
can increase the chances of a mudslide.
As water rapidly accumulates
in the ground,
it saturates the rock, dirt and debris.
This makes the slope unstable.
So the mud flows down,
covering and destroying
everything in its path.
In the U.S., mudslides cause $3.5 billion
in damage
and kill up to 50 people each year.
And worldwide, between 1998 and 2017,
landslides and mudslides affected
more than 5 million people
and killed more than 18,000.
Mudslides can devastate roads
and even entire communities
located near a slope.
If you’re in the path of a mudslide,
you must escape.
But don't try to run downhill.
You can’t outrun a mudslide
as the rock, dirt and debris they carry
can travel up to 56 km/h (35 mph).
Instead,
go to the side of where the mudslide
is flowing to avoid getting caught
in its drift.
Finding shelter should be your last resort
as mudslides can swipe entire houses
with them
or even bury them.
But if you can’t escape the mudslide,
you’ll need a good shelter at home.
Unlike what you might do
in other natural disasters,
don’t hide in the basement.
Instead,
get in the bathtub,
as it will protect you from the mud
that can solidify very quickly
once the water escapes.
Deforestation can remove
protective natural drainage systems
and make the soil prone to collapsing.
As more people moved
to Sugar Loaf Mountain
in Freetown, Sierra Leone,
they uprooted many trees to build houses.
In 2017, a heavy rainfall that flooded
the town caused a massive mudslide
and killed more than 1,100 people.
Building adequate drainage systems
for slopes
and building houses in safe locations
are the best ways to prevent mudslides
from killing people.
Unlike natural disasters
that are predictable,
mudslides are typically unexpected.
And there aren't many warning signs
other than heavy rainfall.
If you see a sudden rise
in the local water level,
that could be an indicator
of debris flow upstream during rain,
immediately evacuate the area
and alert the authorities.
A trickle of mud flowing down
can also be a sign
of a developing mudslide.
You can also look for tilted trees,
power line poles or walls
indicating a shift in the land.
In 2014, in Oso, U.S.,
21.3 m (70 ft) of mud on a slope
swallowed a nearby river,
1.6 km (1 mi) of a state highway
and parts of the town.
A hillside collapsed,
sweeping over the town
in a massive mud flow
that injured 10 people and killed 43.
Scientists believe that previous mudslides
and slope erosion during the 1930s
contributed to this enormous mudslide.
And since then,
numerous mudslides have occurred
due to heavy seasonal rainfall.
It’s important to know if mudslides
have occurred in your area
so you can develop an evacuation plan.
You survived a mudslide,
but the rainfall hasn't stopped,
and it looks like that river
is about to overflow.
Could you survive a flood?
Find out here.