All language subtitles for D D S01E05 Mudslides 1080p AMZN WEB-DL DD2 0 H 264-playWEB_track3_[eng]

Landslides are among the most
destructive forces in nature.

They occur with devastating
speed and deadly consequences.

Nothing can be done to prevent
a mudslide once it starts,

as its power tears away
everything in its path.

One of the most
shocking examples

occurred in a Welsh mining
village called Aberfan,

when an entire generation
of children were wiped out,

as their school
was engulfed by a mudslide.

We also look
at the devastating landslides

to hit California
early in 2018...

as well as the loss
of an estimated 30,000 people,

who were buried
or swept out to sea

when a devastating series
of landslips

wiped out a 100-kilometer-long
coastline of Venezuela.

A mudslide, or debris flow,

to give it its proper,
technical name,

is a moving mass of loose mud

mixed with
a combination of sand,

soil, rock, water and air

that travels down a slope
pulled by the force of gravity.

To be classified
as a debris flow,

the moving material
must be loose

and more than half
of the solids in the flow

must be larger
than sand grains.

The debris flow can contain
material the size of gravel,

pebbles, cobbles
and even boulders,

and may reach
terrifying speeds

of up to 160 kilometers
per hour.

On the opposite end
of the scale,

a debris flow can be so slow

that it will only move down
a slope a few meters each year.

A mudflow, on the other hand,

consists of a mass of water

and particles the size of sand
or even smaller.

It will cascade rapidly
down a stream,

canyon or ravine,

and may prove to be
just as deadly and destructive

as a debris flow.

Mudslides occur after water
quickly saturates the ground

on a slope.

One of the key things
about debris flows,

or mass movements on the slope,

is that they’re usually set off
by water.

Not all of them,
but the majority of them.

Particularly, the mudslides
that we’ve got in this episode

all require water.

So one of the first things
you need to do

is make sure your slopes
are well drained,

and actually remove that hazard
from the slope, if you can.

This is often caused
by heavy rainfall

or rapidly melting snow.

Because they need water
to form,

mudslides tend to happen
during wet seasons.

They can also be triggered
by earthquakes.

A landslide
that occurred in 2008

as a result
of the Wenchuan Earthquake

in China’s Sichuan province
killed 20,000 people,

roughly a quarter of all the
deaths attributed to the quake.

Other causes of landslides
include volcanic eruptions,

a change in the level
of groundwater,

repeated freezing
followed by thawing,

and erosion that leads
to slopes becoming steeper.

Changes to a hillside
caused by human activity

such as construction
or deforestation

can also contribute
to mudslides.

In 2014, a deadly landslide
in Washington State,

which killed 44 people,

was blamed by many
on deforestation.

Years of chopping down trees

had stripped the hillside
of strong roots

and left it vulnerable
to the effects of heavy rain.

Construction of roads and housing,

and uncontrolled changes
to land,

such as not draining
an area properly

before building on or near it,

can create the conditions
ripe for a mudslide.

Wildfires, which destroy
the roots of plants,

may also lead to mudslides.

This is because the roots
help bind the soil together,

making it stable and less
likely to be swept away.

Overgrazing by farm livestock
can have the same effect.

Another contributing factor

may be the dumping of debris
and other landfill

into channels
where mudflows can occur.

Water breaching a dam, levee,
irrigation ditch

can also cause mud
and debris flows

as the escaping water
quickly mixes

with large amounts
of loose soil.

Often the sheer weight
of matter such as snow,

stockpiles of ore
and other waste materials

can put pressure
on unstable hillsides

and unleash
a terrifying mudslide.

As it moves downhill,

a mudflow can sweep up
nearly anything in its path,

including debris
left by previous flows.

As it gathers more material,

the flow will increase
its erosive power

and destructive energy.

In the United States,

landslides result in an average
of 25 to 50 deaths per year.

Throughout the world,

the highest number of people
killed by landslides

occur in
various parts of Asia,

Central and South America,

and in the Caribbean.

Just between 2004 and 2010,

scientists have calculated

that landslides
killed over 32,000 people--

Or more than 4500 individuals
per calendar year.

There are many strategies
that can be put in place

to decrease the risk
of mudslides.

A lot of things
are already being done.

We can already start to work out
where they’re likely to occur.

We can model
the way in which they move,

using computer
simulation techniques.

We can identify the conditions
that trigger mudslides.

We can ensure that there’s
planning regulations in place

to ensure people avoid the areas

where mudslides
are going to occur.

And we can put up some form
of mitigation measures.

We can build check dams

to stop mudslides
affecting an area.

We can make sure
there are evacuation plans.

You have warning systems
in place

so that people can be evacuated.
So a lot is being done.

We can look at the geological
conditions that exist,

where the ground
has shown itself

to be susceptible
to mudslides.

So we can identify a lot

about where the mudslides
are going to occur.

What we say
with things like mudslides

is that they’ve got
many different causes,

but, in fact,
there’s only one trigger.

There’s some single event that
usually triggers the movement.

What we got to do is see
what the other conditions are,

identify them, and then
anticipate the trigger.

And most of the time,
the trigger will be

a period of sustained
and heavy rainfall.

There are a variety
of features

that engineers can put in place
to armor a slope

and prevent it
from giving way.

Majority of cases I’ve seen,
usually, for example,

along the sides of motorways,
you might see either gabions,

which are like, sort of,
like metal baskets

with rock material inside.

And again, they’d have
drainage through them

to allow water to get out.

Because if you get
the water in there,

it’s still going to go.

Another approach might be
to use large,

really large boulders,
very large boulders,

5 meters across,
something like that,

basically,
to protect the slope.

During rainfall,

experts recommend
extreme caution

on or around steep slopes,

and looking out
for visible signs

that a landslide may occur.

The sorts of indicators
that a slope might fail

can be very varied.
If you’re on the slope itself,

away from the buildings,

generally,
what you’d be looking for

is terrain or a slope
that looks a bit different.

Usually, it might look a bit
hummocky, for example.

There might be cracks in it.
You can look at the trees.

The trees may not
be growing vertically.

They may have
some asymmetry to them,

because trees
like to grow upwards.

But if they’re being forced
down the slope,

then they might have some
asymmetry to their growth.

So you might see things
like that.

But primarily, the first thing
you would look for

is that different texture
to the slope.

If there are buildings
or roads in the way,

you might see cracks
in the road.

You might see bulges
in things like patios,

or tarmac in a road,

things like that, which indicate
the slope is starting to move.

So you can use features
that are both natural

and obviously affecting
man-made structures as well.

The consistency of a mudflow

is rather like pancake batter.

They tend to pick up speed

and grow in size
as they gather debris.

Mudflows are similar
to flash floods

in that they can occur
very suddenly

and are extremely dangerous,

because people may have
little or no warning

of the impending disaster.

Mudflows can scour across land,

leaving deep gouges
and debris,

which can severely impact
agricultural land

and destroy crops.

They can also have a severe
impact on vital infrastructure.

They can rip up
and block roads,

damaging utility pipes
which carry water,

gas and sewage.

Electric pylons
and communication lines

are particularly susceptible,

as they are often constructed
with weak foundations.

Such damage to infrastructure

is liable to hamper
relief efforts.

If a landslide
reaches a river,

the mud and rock
will flow into it

and can eventually
reach the ocean.

This can cause large silt
deposits on the riverbed,

which is harmful
to marine life,

as well as local
human populations

and animals
relying on the water.

The potential upside

is that the nutrients
brought down by the slide

will improve the quality
of plant growth in the water

and so, eventually, enhance
the life which depends on it.

The deadliest types of
mudslides are called lahars,

which are associated
with volcanic activity.

They are often caused
by a sudden

and catastrophic
melting of ice and snow

from the heat
of the volcano.

The lahar,

which has the consistency
of freshly mixed concrete,

has a terrifying power

that can destroy anything
that stands in its path.

Lahars can also occur
when heavy rain

makes volcanic deposits of ash

suddenly break loose
from a mountainside.

The deadliest mudslide
in recorded history

was a lahar that occurred
in 1985 in Colombia,

following the eruption
of a volcano

known as Nevado del Ruiz.

The eruption resulted in
a devastating series of lahars

that swept down the mountain
towards the city of Armero.

Residents were buried under
nearly 5 meters of debris.

Of the 28,000 people
living in Armero at the time,

barely 5000 survived.

It wasn’t simply
the worst natural disaster

in Colombian history,

but one of the worst
natural disasters

ever to occur on Earth.

As with any natural disaster,

the cleanup after a landslide

can be
an enormous undertaking.

Fortunately, developed nations
have strong systems in place

to help affected areas
get back to normal.

But even they
are sometimes challenged

by the sheer scope
of the relief effort necessary.

In the United States,
mudslides cause

an estimated $1 billion worth
of damage per year.

For developing nations,

there is often less money
and fewer plans in place.

They also suffer
disproportionately

when it comes to casualties.

This difference is due
to a number of things,

including the efficiency
of basic infrastructure

and emergency services,

and the access of health care

to treat people who are
injured or left homeless.

Tackling poverty and improving
construction standards

in high-risk areas
may go a long way

towards stemming the flow
of losses from landslides,

as well as other deadly
natural disasters.

They become a serious threat to
humans

who chose to live
in active mudflow areas.

Although as climate patterns change,

previously safe areas

may well be considered
dangerous in the future.

California,
on the west coast of America,

is particularly prone
to landslides.

More than 100 residents
have been killed by landslides

during the last 25 years.

The majority
of deaths occurred

when people were buried
by debris flows

while they slept
on the ground floor of houses

situated near dangerous slopes.

California is affected
by earthquakes,

wildfires and heavy rainfall,

all of which are major
contributing factors

to mudslides.

But they are difficult
to predict,

because there is
often a delay between rainfall

and the triggering
of a landslide.

In Los Angeles in 1998,

serious landslides occurred

five days after the rain
had stopped.

In some cases,
it has taken weeks

before the effects
of heavy rainfall

caused the land to give way.

A shocking example
of the power of mudslides

occurred in 2018
in the small town of Montecito,

home to some 9000 people.

Leading up to the mudslide,

the community had already
experienced severe weather.

The 2017 wildfire season
had been the most destructive

in California’s history,

burning over 5300
square kilometers

and killing 46 people.

But what lay behind
those terrible wildfires?

Up until 2016,

there had been
a five-year drought,

amongst the worst
in history,

which had parched
the landscape.

The drought ended
with record rainfall,

producing lush vegetation,

which then turned to kindling,

following the hottest summer
on record.

At the beginning of December,

the coast of California was
swept by the Santa Ana winds,

comprising of warm
and extremely dry air

from the deserts inland.

They fanned wildfires across
the southern part of the state,

which were made worse
by the lack of rainfall

during what is normally
the region’s wet season.

In late December,
the Thomas Fire,

one of the largest wildfires
ever to hit California,

ravaged over 1000
square kilometers

of the Santa Ynez Mountains.

It scorched whole areas

of Santa Barbara
and Ventura counties,

burning large amounts
of vegetation.

This destroyed the roots

that supported the surface soil
on hillsides,

leaving them much more
vulnerable to landslides.

On the 5th of January 2018,

a strong low-pressure system

and cold front developed
off the coast of California.

The danger to those communities

living in the shadow
of the parched

and burnt-out mountains
was immediately obvious.

Residents of Montecito

were issued with compulsory
evacuation orders.

The authorities were aware
of the extreme danger,

largely due to research
that had been done

by the U.S. Geological Survey.

They had studied data from
past extreme weather events

going back decades,
and created models

that could predict precisely
how much rain would be needed

to trigger a mudslide
in any given area.

As the storm approached
the Californian coast,

authorities were able to issue
the first warnings

days before
the mudslides occurred.

By Monday, the 8th of January,

the weather system
reached the mainland

and unleashed
a vicious winter storm.

After almost a year
of drought,

Southern California was deluged
by extremely heavy rain.

There were
mandatory evacuations

in parts of Los Angeles,

Santa Barbara
and Ventura Counties,

due to a risk of mudslides

in areas which had previously
been affected by wildfires.

Over 21,000 people were
supposed to leave their homes.

Many ignored the warnings.

Only around 10 to 15 percent

of Santa Barbara County
residents evacuated.

What intrigues me always
about these sorts of events

in developed countries
is that often the loss of life,

although tragic, is usually
a lot lower than it is

if you go
into developing countries.

I think it was something like
21 people killed in this event.

But the actual infrastructure
damage was just huge.

This is one of the events
that I believe

was being anticipated,

and evacuation plans
were in place.

And again,
that’s something you do see

in many developed countries.

that they actually have
evacuation plans in place,

and they appear to have been
very effective.

However, there’s always
a problem with evacuation plans

because if you evacuate
people too often,

they sort of suffer
from fatigue of evacuation

and tend to ignore
some of the signs.

And that’s of concern.

And I believe that happened
in Santa Barbara.

I decided not to evacuate when
I got the warning on my phone,

because it was in the middle
of the night--

Well, 2 or 3 in the morning.

And my concern was
if I evacuate,

I might get trapped in my car
with flowing mud.

Many people had just
stopped believing

that disaster
would strike them.

They were tragically wrong.

At 3:30 a.m. on the 9th
of January 2018,

a thunderous river of slurry

descended off the hills
into the heart of Montecito.

By the time the mudslide
hit the first few homes,

it was so powerful
that it was carrying

rocks and boulders
the size of cars

from the Santa Ynez Mountains
down creeks and valleys.

Survivors reported
that the flow

sounded like a freight train
and came in an instant,

as if a dam had broken

and completely engulfed
their houses.

The debris flows were
up to 5 meters in height,

moving at speeds
of 30 kilometers per hour.

The devastation
was spread over an area

of nearly 78 square kilometers.

Over 20,000 people lost power,

100 homes
were completely destroyed,

and 300 damaged.

Firefighters who first arrived

said the area looked like
a First World War battlefield.

They had to pick their way
through debris,

piles of fallen trees,
and around displaced boulders,

in a desperate attempt
to find survivors.

For most people that are here
on this incident,

we’ve never seen
an event like this.

This is very unusual to have
something to this magnitude.

Search crews made up of rescue
workers and citizen volunteers

were also sent out
to locate the missing.

They used long poles
to probe the mud and slurry

trying to locate bodies.

Power lines were down.

The large aluminum poles
that held them in place

had been snapped in half.

Water was pouring
out of shattered pipes.

A mandatory evacuation
was ordered,

and thousands of people
fled the area.

First responders performed
more than 50 rescues.

Crews in helicopters hoisted
survivors from mud and debris.

Rescue workers used
all-terrain vehicles,

but the search for survivors
was hampered

by roads blocked by rocks,

fallen trees
and downed power lines.

A 50-kilometer section
of the coastal Highway 101

from Santa Barbara
to Ventura

was completely shut down,

as sections were filled
with 60 centimeters

of mud and debris.

Access to Santa Barbara
from the Los Angeles area

involved a 420-kilometer detour

around the Los Padres
National Forest.

Some relied on private ferries

between Ventura
and Santa Barbara

to bypass the closure.

By the 11th of January,

two days after the disaster,

anxious relatives
were still waiting for news

of missing loved ones.

Governor Jerry Brown estimated

that the search
could take weeks,

though he still had hope that
people would be found alive.

By Friday, over three days

after the mudslide
struck Montecito,

the confirmed death toll
had reached 18.

We just feel very sorry

for the people who lost
their homes and their lives.

How do you describe it?

It’s devastating,
what happened.

Uh, so much destruction.

Over 1200 emergency workers
were in a race against time

to find the five people
still unaccounted for.

Meanwhile,
heavy equipment was brought in

to help the cleanup effort.

Crews from Caltrans,

the California Department
of Transportation,

cleared nearly 4 meters
of mud from the highway.

And on the 21st of January,
five days into the crisis,

Highway 101
was fully reopened.

A total of 21 people
were killed by the mudslides,

another 28 were injured,
four of them critically.

But casualties in Montecito

would most likely
have been even greater

had it not been for warnings

from scientists
and government agencies

in the days and hours
leading up to the tragedy.

In the mountains
of Southern California,

there is a terrifying cycle
of wildfires and debris flows.

There is even a possibility

that this cycle
is getting more intense,

due to changes in the climate

and increased
human development.

The average
wildfire season lasts

two and half months longer
than it did in the 1970s,

and the area of land
burned since 1984

is twice what scientists
at the time predicted.

If you extend the actual length
of the period for the fires...

is that if you enter
into the season

where you’ve then got snow
on the higher ground,

the dust, or the soot,
from the actual fires,

can actually,
if it lands on the snow,

can actually encourage
the snow to melt more quickly,

because it’s changed
its reflectivity,

so it’s albedo.

And so you melt the snow,
you get more water.

Therefore, more erosions.

Science is starting
to understand

how the cycle works,

and provide some idea

of when it will be
at its worst.

This information will be vital

if people continue to build
more and more houses

at the feet of mountains

that regularly unleash
their debris flows.

If wildfires
are becoming more common,

it is more likely that the
mountainsides will give way.

And it is not only the roots

that hold the underlying soil
together that is burned away.

Even the creatures
that live in the soil

and would normally aerate it,

helping it
to better absorb rainwater,

are killed by the fire,

as well as the ground cover

that provided protection
against the downpours.

The plants that thrive

in Southern California’s
chaparral,

the shrubby heathland
that typifies the area,

play a particular role
in the problem as well.

Those shrubs
and lie-lowing waxy plants

have a resin-like coat
on their leaves

that helps them
to retain moisture,

enabling them
to survive drought.

The relationship between
wildfires and debris flows,

or mudslides,
is quite interesting,

because what tends to happen
if you’ve got a wildfire

is the superheating
of the ground can release,

from the vegetation,
it burns the vegetation,

and it can release the waxy
substances from the plants.

They come out mainly as a kind
of vapor, and it can solidify,

usually below the soil surface,
around the soil particles.

And it forms this, what they
call "hydrophobic soil."

It sheds water, and it won’t let
water pass through

the actual soil profile.

So that means you’re more
likely to get soil runoff,

and then that can take with it
mud and debris

and sediment
from the surface,

and can lead to all sorts
of erosion problems.

Elevation and the relief,
in other words,

of the highest to the lowest
point in a catchment

is actually quite important.

If you’ve got steeper slopes,
you’ll get more runoff.

And therefore, you’ve got
less stable slopes, generally.

With regard to generating
debris flows,

you’re more likely to generate
them on steeper slopes.

The mudslides in Montecito

are a tragic reminder

that natural disasters
threaten many U.S. homes,

even within prosperous
neighborhoods.

Aberfan, a tiny mining
village in Wales,

could not be more different

to the affluent coastal
community of Montecito.

At 9:15 a.m. on the morning
of 21st of October 1966,

this small village
was plunged into despair

when thousands of tons
of waste from a coal tip

roared down a hillside,

engulfing a school
and several homes.

The village of Aberfan

is a community that grew up

around the Merthyr Vale
colliery.

Merthyr Vale
started operating in 1869,

and was once one of the largest
of the 600 coal mines

that were so crucial
to the development of Britain.

Coal was so vital
to the economy of the time

that it was known
as black gold.

It powered
the Industrial Revolution,

which enabled Victorian Britain

to become the world’s
superpower of the time.

But by 1966,

the importance of coal
was in decline,

replaced by oil,

and several pits
had already closed.

In Aberfan,

the number of miners had fallen
from over 2000 to about 800.

But it was still considered
vital to the local economy.

Since the coal industry
had been nationalized

after the Second World War,

the National Coal Board,
known as the NCB,

had taken control
of U.K. mining

and wielded enormous power.

It was seen as the protector
of a dwindling coal industry

and was treated with a respect
bordering on reverence.

For around 50 years,

waste material from the nearby
colliery, known as "spoil,"

had been tipped
in a series of slag heaps

onto the tops
of the surrounding hills

above the village.

In the center of the village,

directly below one of the huge
heaps of spoil

known simply as Tip Number 7,

lay Pantglas Junior School.

Tip Number 7 had been growing
for nine years,

and by 1966 contained nearly
300,000 square meters of waste,

towering 34 meters high.

The children
in the back classrooms

would have been able
to see the enormous tips

through their window.

There was a regulation in place
with the NCB

that any mine material dumped

should not be dumped
on top of a spring,

a natural water spring.

And that was ignored
at Aberfan.

Numerous complaints
had been made

about the dangers
of the tip,

including a petition
from Pantglas school,

which lay in its shadow,
but the NCB dismissed them all.

They made it clear that
the cost of moving the tip

would make the mine
unprofitable.

In the days
leading up to the disaster,

there had been heavy rain.

At 7:30 a.m.,
on the day of the disaster,

a crew arrived at Tip Number 7
to begin work.

They quickly noticed
something unusual.

The tip had clearly moved,

and the track
that their crane stood on

had been bent about 3 meters.

Since they had no telephone,

a worker was dispatched
to go down on foot

to report the problem.

But no alarm was raised.

Nearby,
excited children set off

on their last morning
of school

before the half-term
holidays.

As they made their way
along the narrow lanes

that separated
the miners’ terraced houses,

they could have no idea
of the horrors that lay ahead.

By 9 a.m., the tip had subsided
by another 3 meters.

Minutes later,
a vast wall of mud and rocks

smashed into the side
of the school

at over 34 kilometers per hour.

We just looked
up at the windows,

the front windows,
facing the tip,

and you could see like a black--

Like a black mass,
like locusts.

Just a mass
coming into the classroom.

The slide continued
its path of destruction,

engulfing a whole row of houses
in the village

before finally coming to rest.

There was this rumbling sound

which got louder and louder
as time went by.

And the next thing I remember
was waking up.

When I woke,
I found myself in this, um...

covered in this material...

with a dead girl
on my shoulder.

And I couldn’t move.

There were screams and shouts,

and obviously they got less
and less as time went by.

Hundreds of villagers
who rushed from their houses

were faced with a scene
of utter devastation.

A large part of the school
was buried

with their children inside.

Only the shattered roof
was visible

above a black sea of slurry.

As news of the disaster
spread,

the emergency whistle sounded
in the colliery.

Miners emerged
and ran to the school.

Many of their wives
were already there,

clawing at the slurry,

some with no skin left
on their hands,

desperate to reach
their children

who were crying for help,

children that only
a few minutes before

they had waved off to school.

Doctors and nurses set up
a triage in the playground

at the school’s entrance.

Men and women of the community

carried the injured children
to the triage,

where they were assessed
by the waiting medics

and provided with first aid.

The area was declared
a disaster zone,

and the seriously injured
were taken to hospital.

Roads for miles around
became gridlocked

as emergency services,
the Army and Civil Defense,

tried to get to the scene.

They were joined by miners
from surrounding pits,

as well as thousands
of volunteers.

First local,
then national

and eventually
international media,

descended upon the village.

Aberfan was the first
British tragedy

to be covered extensively
on television,

as the scale
of the catastrophe unfolded

in pictures which were
beamed around the globe.

The plight of Aberfan horrified

and deeply moved
the watching world.

In all,
just 35 people were rescued

out of the mass
of coal slurry and debris.

The last rescue
occurred at 11 a.m.

After that, it was only bodies
that were found.

Specialist officers arrived

to set up
a temporary mortuary.

They needed to take the bodies
somewhere nearby,

and decided on Bethania Chapel,

which was just down the road
from the school.

The grief of their relatives
is almost unimaginable.

As darkness fell,

arc lights were set up
so they could continue to dig

all through the night.

The following day,

both Lord Snowden,
husband of the Queen’s sister,

and later the Duke
of Edinburgh,

walked among the 2000
emergency service personnel

and volunteers who were working
in the disaster area.

Many of them had been laboring
continuously for over 24 hours.

It was nearly a week before
all the bodies were recovered.

Nearly half of the pupils

at Pantglas Junior School
lost their lives.

They were between the ages
of 7 and 10.

Five of their teachers
also died.

Most of the victims were buried
in the village cemetery

at a joint funeral
that was attended

by more than 2000 people.

Today, the site of what once
was Pantglas Junior School

is a memorial garden on
the outskirts of the village.

A peaceful place
with wide, paved borders,

trees and bushes.

It’s almost impossible
to believe

that we have to have a tragedy

before we deal
with the consequences.

That’s exactly what happened
at Aberfan.

Aberfan resulted
in all these tips,

you know, if you know the area,

there were an enormous number
of tips

which were perched
above villages in the area.

And, you know, they could easily
have failed as well.

And evidence was ignored,
it just wasn’t accepted,

even at the NCB.

Because no miners were killed
underground,

in theory, they didn’t even
need to report the fact

that this tip had failed,

because that wasn’t deemed to be
part of their responsibility.

You know, it’s an
appalling situation,

and a savage indictment
on the regulations

that were in place at the time.

Aberfan was a tragic event
caused by a single landslide.

It would seem unimaginable
that such a phenomenon

could occur more than once
in a century.

But over the course
of a nine-day period

in December 1999,

torrential rains fell
on a mountainous region

of Venezuela,

causing another flow
of deadly mudslides

that devastated
the state of Vargas.

The landscape of Vargas
is extremely steep and rugged.

The distance between the coast

and the 2700-meter peaks of
the Sierra de Avila mountains

is only 6 to 10 kilometers.

The rivers and streams
of this mountainous region

emerge from steep canyons
onto flat alluvial fans,

before emptying
into the Caribbean Sea.

These alluvial fans
are triangular in shape,

and are formed
by deposits of sand,

gravel and silt,
brought down by water

flowing off the slopes
of the mountains.

In Vargas,
little relatively flat land

was available for development,

with the exception
of the alluvial fans.

This coastal city was popular

because of its proximity
to the capital,

which is only
30 kilometers away

and is easily accessible

via a pass
through the mountains.

Many residential communities
had developed

as well as a thriving
tourist economy.

Venezuela’s main airport,
the Simón Bolivar,

and the major seaport
of La Guaira,

which handles around a third
of all of Venezuela’s trade,

are also situated
in the state.

Because of this,

many people were drawn
to work in the area.

But with the flat
alluvial fans

already heavily built on
for resort towns,

newcomers had no option

but to settle on the steep
hills and canyons.

This had a great impact
on the life of the poor.

They were known to be
dangerous, but for many,

they were the only homes
available.

Many of these coastal towns

were developed
in a bizarre way,

with luxury hotels,
harbors for yachts,

and high-end
apartment buildings

in view of the shanty dwellings

clustered on the hills
above them.

Although scientists had known
of the dangers from landslides

in the area, no hazard maps
were ever produced,

or warning systems
put in place.

This, despite the fact that
during every rainy season,

which normally runs
from March to October,

about 200 homes were estimated
to have been swept away

by rain and mud.

The best way to avoid
any form of landslide,

of which mudslides are a type,
is basically,

to not build in their path,

to identify where the areas
that are susceptible

to any kind of movement,
and just avoid them.

And that’s proper planning
regulations.

You have the right
regulations in place,

properly instigated
by the authorities,

and therefore, you can avoid
a lot of the problems.

There are so many shantytowns
built up

around major areas of population
with no regulation whatsoever,

and often these are in
very vulnerable places.

The weather in 1999
was by no means normal,

with torrential rain continuing
into November and December.

The reason for this unusual
out-of-season rainfall

was a cold front that settled
over the coastline,

interacting with the moist air

flowing south
from the Pacific Ocean.

Rain fell continuously
for 16 days,

and the ground
was completely saturated.

On the 2nd and 3rd
of December alone,

rainfall amounting
to 20 centimeters

fell in the region.

But even worse would follow,

when a major storm
inundated the area

with over 90 centimeters
of rain

between the 14th and 16th
of December.

Many thousands realized
the danger they faced,

and fled the region
to higher ground.

Many people were unable
to get away in time,

and were still in their homes
when the landslides hit.

Unable to absorb
anything more,

the soil finally gave way.

Numerous floods
and debris flows occurred

in the later hours
of the night

of the 15th of December,

persisting right through
to the afternoon

of the following day.

Avalanches of wet mud
and debris

began hurtling
down the hillsides

in a maelstrom that tore away
everything in its path.

The flow,
which was up to 9 meters deep,

hurtled down the slopes

at speeds of 60 kilometers
per hour,

carrying huge rocks,

some as big as 9 meters
in diameter.

With little or no warning,

thousands of people
were swept away,

as their homes collapsed
in the seething mudslide.

Houses lower down the slopes
were destroyed

when the buildings above
collapsed onto them.

In some cases,
entire neighborhoods

were obliterated in a moment.

Shantytowns and whole villages
were buried beneath the mud

or swept out to sea.

Entire towns like
Carmen de Uria and Cerro Grande

were completely obliterated.

In Carmen de Uria,
an estimated 10 percent

of the town’s
5000 inhabitants died.

Of the 3000 houses
that once stood there,

only around 100 were spared

the destruction
wreaked by the mudslide.

The once bustling streets
and open markets

were reduced
to a muddy gorge,

strewn with boulders
and rubble from buildings

torn apart in the deluge.

The avalanche of water,
mud, trees,

and the wreckage
of houses

came to a stop at the bottom
of hills and mountains,

where it engulfed high-rise
apartment buildings.

Many people were stuck
on rooftops for days,

completely cut off
by mud and debris.

More than 8000
individual residences

and 700 apartment buildings
were damaged or destroyed.

Every aspect of the state’s
infrastructure...

vanished within minutes.

All utilities,
telephone, electricity, water,

and sewage systems
were severely disrupted.

The whole state was virtually
cut off from the outside world.

People were unable to find out

what had happened
to their loved ones.

Local television stations

allowed relatives
to appear on-air

with photos and messages

in an attempt to help them
get the information

they so desperately needed.

For weeks, there was no access
to relief supplies,

and hundreds of thousands
were evacuated from the area.

One thousand survivors
took shelter on a golf course

near the resort of Caraballeda,

where they waited
to be evacuated.

They were attended to
by 18 doctors

who worked for days
without respite.

By an unfortunate coincidence,

the disaster coincided with
a major government referendum

that was being held
at the same time.

Hugo Chávez, who had been
sworn in as president

just 10 months earlier,

was seeking a mandate
to ratify a new constitution.

Many accused the government

of not executing disaster
relief quickly enough,

because military
and police resources

were too heavily focused
on tasks related to the voting.

On the 15th of December,
as the crisis deepened,

there were widespread reports

that looting
had become rampant.

President Hugo Chávez
called in the military,

with a remit to aid
in evacuation efforts

and to restore order.

By the 20th of December,
the authorities realized

the seriousness
of the situation in Vargas

and declared
a state of emergency.

Three hundred and fifty
thousand people,

mostly the very poor,

were left homeless
by the terrible storm.

Although all members
of society were affected,

it was the poor in shantytowns
who suffered most,

as their flimsy dwellings
were swept away

in the raging mud
and water.

The American
and Venezuelan Red Cross

joined the relief effort,
setting up bases

so that victims
could have access

to food and medical care.

Many nations sent assistance

in the aftermath
of the disaster.

They joined 13,000
Venezuelan soldiers

who led the relief efforts.

The international community
realized that Venezuela

was in the midst of one of its
worst-ever natural disasters.

There was clear evidence
of lots and lots of mudslides

coming down through the village.

The area was cut off for
a considerable amount of time.

One of the issues
I remember most about that

was that they
had to evacuate

something like 80,000 people
from the area,

and they had to declare martial
law just to protect the area.

The mudflows in this area
flowed out into the sea,

so you couldn’t actually work
out how far they ran out.

But again, it seems to be the
result of very heavy rainfall,

and a lack of planning in where
the developments took place.

The World Bank
quickly stepped in to help

with an offer to loan
the stricken nation

$150 million U.S. dollars.

Hundreds of thousands
of people

remained homeless for many
weeks after the mudslides.

The official estimate
for the death toll is 30,000,

although it could be as high
as 50,000.

At the time, this represented
well over 10 percent

of the estimated population
of Vargas.

A true figure of the human
cost will never be known,

because so many people were
buried or carried out to sea

by the debris flows
and flooding.

Only about 1000 bodies
were ever recovered.

And the fact that it was never
known how many people

were living in the shantytowns
before the mudslides

further complicated the task
of getting accurate information

about the number of deaths.

Estimates of the cost
to rebuild

the ruined infrastructure,

and deal with
the 150,000 people

who had lost their homes,

was put at between
4 and 15 billion U.S. dollars.

The sheer volume of debris,

rocks and large boulders hauled

make the 1999 event

amongst the largest
rainfall-induced debris flows

ever documented.

The disaster
highlighted the need

for the country
to rethink its land development

and environmental policies.

Plans were drawn up
to create new dams

and dig long canals to prevent
a repeat of the disaster.

But 10 years later,

many of the once-thriving
coastal communities

were like ghost towns.

Apartment blocks and holiday
villas remained derelict,

with boulders and dried mud

lying where they settled
during the fateful disaster.

And, tragically,
there were people for whom

those wrecked
buildings were home.

If you can’t plan
to stop development,

then you have to fall back
on remedial treatments.

And we do have those in place.
They are available.

Add to that, you do need to have
some monitoring systems.

You need to ensure that
you have evacuation plans.

And at the end
of the day, yes,

you do need to have
emergency plans in place

to deal with the aftermath.

And again, the developed world
is so much better,

because it has the resources
to have such things in place.

The developing world
is where those plans--

Maybe they’re there in theory,

but rarely there are
the resources there

to just have plans ready
and get things moving quickly.

There can be few more
terrifying experiences

than seeing a solid hillside
turn into a fluid mass,

capable of smashing through
everything in its way,

bringing death and disaster

on a murderous path
to the valley floor.

The landslide is truly

one of Mother Nature’s
most horrific killers.