All language subtitles for Apocalypse Earth Series 1 Part 5 Frozen Fury 1080p

(tense music)

- [Narrator] It can be
a stone cold killer.

And centuries ago, millions
fell victim to its wrath.

- [Kyle] If a hundred mile
per hour chunk of ice hits you

in the head, it can
very easily kill you.

- [Narrator] How could
ice become so violent

and so powerful as to
nearly wipe out civilization

while carving out some of
America's most natural wonders?

- [Steve] It moved the position
of the Mississippi River.

- [Narrator] And has this
frozen fury of our ancient past

become the slippery slope
towards our future demise?

- As we move into the future,

if the climate state is such
that we can have severe storms

and severe weather events
coming in every year,

adapting to that kind of
extreme is very difficult.

We don't know what
to prepare for.

- [Narrator] Earth,
air, fire, and water,

essential for human survival,

but in their extreme--

- [Man] Coming down right
now, make your turn.

- [Narrator] To everything
and everyone in their path.

- [Man] Oh, big power black.

- Wow.
- Whoa, whoa!

- [Narrator] These are stories

of Apocalypse Earth.

With every bone chilling
winter storm come predictions

of a new Ice Age.

Extended periods
of freezing rain,

blinding snow storms, and
Arctic air lead many scientists

to predict a return
to a frozen earth,

not seen for thousands of years.

A time when our planet was
covered in massive ice sheets

with the power to change the
shape of continents and oceans.

Evidence from the past could
provide key clues to when

and if we return
to another Ice Age.

Some scientists predict
that the world is entering

a period of extreme
climate disturbance.

Freezing temperatures
could grip Europe

and the Northeastern Coast
of the United States,

while other regions suffer
from drought and flood.

It has happened before.
(ominous music)

(bell tolling)

Generations had prospered
in the stable weather

of pre-Renaissance Europe,

but in the 1300s,
without warning,

that predictable world
was turned upside down

by the so-called Little Ice Age.

- One of the things
that happened was that

you had this whipsaw going
to warm, going to cold.

1309 was cold.

1315 was warm.

1317 is cold again.

And creatures and other things
respond in different ways.

You get crops rotting in
the field if it gets too wet

or germinating too early or
never germinating at all.

- [Narrator] The climate
rapidly switched back and forth

between cold and
warm; wet, and dry.

But this initial erratic
climate was only a prelude

to catastrophic changes
of epic proportions.

Over the next few centuries,
(thunder crackles)

the weather continually
fluctuated at temperatures

between 0.5 and three
degrees lower than normal.

This small change was enough
to awaken an icy killer.

- Throughout the Alps and
throughout parts of Europe

and in fact, in North
America, and Canada,

the Eastern Canadian Arctic,

we see evidence that during

The Little Ice Age,
glaciers advanced.

- [Narrator] The difference
of only a few degrees

triggered a self-perpetuating
feedback cycle.

- You make a little more ice,

it reflects more of the sun.

By reflecting the sun,

the sun is not warming us
up and so it gets colder,

so you make more ice.

- [Narrator] As the
glaciers expanded,

the Vikings took the first brunt

of the climate's deadly chill.

- They switched from
being a farming economy

to eating a lot from the sea

because they were having
troubles raising enough

things on their
farms, apparently.

- [Narrator] But as
temperatures continue to drop,

storms and freezing winds
blasted the settlements,

even the sea held
no hope of survival

for the starving Vikings.

- Around Iceland,
sea ice expanded,

and the people couldn't
get out and go fishing.

And they had open boats,
not boats with decks,

so they were particularly
vulnerable to bad weather.

- [Narrator] After
decades of expansion,

battle ax wielding, pillaging,
and plundering Vikings

were defeated by a sudden
drop in temperature.

(tense music)

- Well, 10 super cold years,

including one of the
coldest years on record ever

in about 1355 AD shut
down Western colony

and a hundred years later,

the more Southerly Eastern
colonies shut down.

- [Narrator] The
Vikings who survived

migrated south, assimilating
into populations

living in continental Europe.

Their fearless culture
receded into history.

If it hadn't been for
The Little Ice Age,

the Vikings may have continued
settling in the New World

and today's America would
be a very different place.

By the end of the 14th Century,

Europe was buckling under
freezing temperatures

all winter long.

In a chain reaction ignited by
the cold and stormy weather,

one calamity followed another.

Crops failed and food
shortages spread across Europe.

The freezing cold
blasted through Asia,

but that was only the beginning.

Relentless storms killed
at least 7 million.

The resulting floods produced
a horrific and infamous

blowback effect on Europe.

- Everybody's familiar
with the Black Death,

but the lesser known
story of course

is the role that
climate may have played

in unleashing it.

(ominous music)

- [Narrator] The Black
Death or The Plague

was a devastating pandemic

that ravaged Europe during
the mid 14th Century.

(thunder rumbles)

The drop in temperature
changed weather conditions

causing storm patterns
to shift and intensify.

In the early 1300s,

Asia had a record breaking
series of torrential storms

and subsequent flooding.

Rats carrying the plague
thrived to these conditions.

- The animals that react
at the first are the ones

that reproduced by the zillions
and reproduce very rapidly,

where as the longer lived,
slower reproducing animals

tend to lag.

And so weedy species of every
sort seem to take advantage

of climate change and flood.

- [Narrator] Rats on ships
traveling the trade groups

spread the disease
from Asia to Europe.

An already starving and
weakened population was no match

for the Black Death.

Within five years,
the plague had killed

between 25 and 34
million people in Europe,

one-third of the population.

An estimated 40 million more
died in North Africa and Asia.

Generation after
generation suffered

the relentless pounding of
extreme cold and wet weather,

pushing the starving
peasant to his limit.

- Then there intense
storms and incessant rain.

Crops are rotting in the field.

There's so little sunlight
that you can't make salt

in the summer to
preserve anything.

Diseases, molds, blights,
and everything else

we're beginning to afflict them.

People fell into robbery, they
lost their land, starvation.

They started eating their
livestock, dogs, and cats.

And at some point, they
even ate each other.

- [Narrator] Sophisticated
European societies

quickly crumbled, scratching
at the edges of mere survival.

Starving peasants revolted
against the aristocracy.

The political unrest and an
economic crash in England

were factors in the
American Revolution.

And it was the
poor of 1789 France

that fueled the
French Revolution.

(tense music)

The tragic scope of The
Little Ice Age was staggering.

Millions died horrible
deaths simply because

the temperature
dropped a few degrees.

- You're living on the edge
and you get just a little bit

of a cooling, it can
push you over the edge.

- Little changes in
global temperatures

can have an enormous effect.

A temperature change of
five to nine degrees,

which is also within the
realm of possibility,

would just be unimaginable.

- [Narrator] The small
drop in temperature

that triggered
The Little Ice Age

may have been caused by
a dimming of solar output

linked to a change
in sunspot activity.

(tense music)

Another factor that
intensified the cooling

was something else no one could
have predicted or prevented.

During the Little Ice Age,

at least three massive
volcanoes erupted:

Mt. Vesuvius in 1631,

Mt. Tambora in 1815,

and Krakatoa in 1883.

All spewed particles and gases
into the upper atmosphere.

These particulates
reflected the sunlight back

into the atmosphere,
cooling the earth.

- If you put a lot
of volcanic debris

high into the
northern hemisphere,

it's going to be everywhere
in the northern hemisphere

within just a couple of years.

No matter what part of the
earth is facing the sun

day or night, it's still
going to get less sunlight.

- [Narrator] After six centuries
of death and deprivation,

the weather finally
began to warm.

- So, the Little
Ice Age likely ends,

because the
volcanoes quiet down,

they're not blocking the
sun, and the sun brightens

up a little bit.

So, you have warming
coming out of 1850 or 1900

into the early
part of the 1900s.

- [Narrator] The Little
Ice Age may be over,

but some scientists
see it as a preview

of what could occur again,

this time with even more
devastating consequences.

Coming up.

(speaking in foreign language)

- [Interpreter] How could
a snow cloud of that size

not bury whoever was on
the face when it hit?

- [Narrator] Some experts
believe that global warming

could paradoxically
catapult parts

of the Northern Hemisphere
into a new Little Ice Age.

(tense music)

rn Seaboard

and Western Europe
would be battered

by severe winter
blizzards and ice storms.

(wind howling)

Proponents believe this big
chill would be triggered

by changes in the
Atlantic Ocean.

70% of the earth's
surface is ocean.

90% of all rain
falls into the seas.

It is a colossal reservoir
of water carrying heat

all over the planet.

A huge ocean
current system known

as the Thermohaline Circulation,

which includes the Gulf
Stream circulates warm water

north from the equator,

giving our Northeastern
Seaboard and parts of Europe

relatively temperate climates.

London, England,
and Calgary, Canada

are on the same latitude,

yet London is much
warmer on average.

The reason: the
Thermohaline Circulation,

which brings warm Atlantic
water and air North

to the British Isles.

As the heat is absorbed
into the atmosphere,

the surface water becomes
colder, saltier, and dense.

It sinks deeply,
in effect pulling

the current down behind it.

- So in the winter as the
water gets really cold,

and colder makes it contract
and contracting makes it denser

and then it sinks and
then warm water flows up

to replace it.

- [Narrator] In a self
perpetuating cycle,

the thermohaline
circulation then moves south

where it warms
again at the equator

and continues its
cycle back up north.

This immense system is dependent
upon a delicate balance

between warm and cold water
and fresh and salt water.

Some experts believe
that global warming

could disrupt this
delicate system

and in a worst case scenario
create a mini Ice Age

in parts of the
Northern Hemisphere.

- The oceans are warming.

Almost all the
glaciers on the planet

have gotten smaller over
the last hundred years.

You're getting reductions
in sea ice in the Arctic.

Things are happening
earlier in the spring

and lasting further
into the fall

than they did in the past.

And so this is great number
of indicators that say,

yes, the planet is warming.

- [Narrator] According
to the Big Freeze Theory,

the rise in the ocean
temperatures could
cause a shutdown

in the thermohaline
circulation that brings warmth

to the North Atlantic region.

- The total heat capacity
of the ocean is 1,100 times

that of the atmosphere.

So in my mind we really
should be trying to understand

what's going on in the ocean

to understand our
future climate.

- [Narrator] Researchers
from Woods Hole

Oceanographic Institution
utilize many tools

to study the changing ocean.

Remote-controlled devices
called floaters track changes

in the ocean's condition.

- They're sort of like
weather balloons for the ocean

that drift at depths for 10 days

then come to the
surface reporting

the temperature and
salinity as they rise

and they transmit that
data to a satellite.

And we have a program to
deploy thousands of these

around the global ocean.

- [Narrator] Using the
data transmitted by tools

like floaters, scientists
create computer models

that track and then
project climate changes.

(beeping)

(crashes)

Researchers continue
to find evidence

of a disturbing development:

global warming is melting
glaciers and ice sheets

causing an increase
in fresh water

flowing into the
thermohaline circulation,

a process they call freshening.

This fresh water could throw
off the critical balance

between temperature and salinity

that powers the
thermohaline circulation.

- What it means is
that those warm waters

no longer flow north and they
stopped much further south.

And so all that warmth
that would otherwise warm

the Northern Hemisphere stays
in the south, which means,

for example, there's more
energy in the atmosphere.

There are more extreme
storms and so on,

but critically much
colder in the north.

- [Narrator] Some
experts think that if

the thermohaline
circulation is disrupted,

temperatures could
drop dramatically

in the North Atlantic

leading to a new Little Ice Age

in North America and Europe.

- If the thermohaline
circulation was to shut down,

the average temperature
changes resulting of that

could be anywhere between
eight to 12 degrees possibly,

but that would be on average.

And clearly the extremes that
could resolve from an average

temperature change like that
could be well beyond that.

- England France,
Germany would begin

to resemble Alaska and Canada.

And those parts of the
world, particularly Alaska,

might even get colder still.

- [Narrator] In
the United States,

the Northeast Coast
would be hit the hardest

with extreme temperatures

and more intense
blizzards and storms.

- For example, severity
of nor'easter storms

could easily increase in
a condition where you had

increased storminess,
increased wind

velocities impacting the
eastern North America.

- [Narrator] Some experts
doubt this big chill

would be nearly so dramatic,

that it would in fact
be only a side effect

of the real devastation in
other parts of the world.

In the Pacific, a warmer
ocean will intensify

the El Nino rainstorm cycle
that historically batters

the Pacific Coastline.

- Even a two-degree change
if we were so lucky,

would be double the intensity
or more of the strongest

El Nino we've ever felt.

In 1998, there was a
very strong El Nino,

did $100-billion damage
around the world and killed

tens of thousands of people.

So, even a very slight
variation from the norm

in global weather can
cause a lot of damage.

- [Narrator] In
the South Atlantic,

warmer oceans will mean
intensified hurricanes

and massive storms.

- The fact that we have a
great deal of heat built up

in the ocean means that
there's plenty of fuel

for more intense hurricanes.

So it seems inevitable
that strong hurricanes

are in our future.

- If we get not
just one Katrina,

but if we get five
Katrinas per year

coming into different
regions of the Gulf coast

or in fact shifting to
where now these storms

are impacting along
the eastern seaboard

and coming into Washington
DC and New York City,

then the consequences
would be severe.

- [Narrator] And warming
oceans and warmer air

could threaten the largest
source of frozen fresh water

on the planet, massive
ice sheets at the poles.

Melting those could
result in floods

never before seen on our planet.

Snow and ice can rapidly
become a deadly mix,

especially for hardcore
adventure seekers.

(tense music)

The Himalayas.

This mountain range
in Nepal is home

to the 14 highest
peaks on earth.

It's most treacherous, the
one known is Annapurna.

- You have a mountain
that's over 26,000 feet

and a canyon right
next to it going down

to only three or 4,000 feet,

so the vertical relief
is just amazing.

- [Narrator] But
it's a hidden danger

that gives Annapurna her
deadly reputation: avalanches.

- Over 40% of the climbers
who attempt Annapurna

do not come home.

For comparison, Mount Everest,

which is the tallest mountain
on the planet only has about

a 9% death rate.

- Looking at Annapurna you
can see why the avalanches

are so prevalent.

See those dark rock layers
leaning out of the hill,

looking like slides in a
playground for the snow

to slide off of and see that
U-shaped glacial valley there

acting like a funnel
funneling the avalanches down.

And for some reason, the
climbers like to go up that,

but that's like playing
Russian roulette.

One out of five of them
are going to be killed.

- [Narrator] In
the fall of 1997,

Annapurna is heavy with a
million tons of fresh snow

lying in wait for
her next victims.

On a year long quest to scale
the world's highest peak,

veteran mountain climbers
Jesus and Jose Novas

had been in the
Himalayas for months.

To document their
triumph over Annapurna,

the brothers hire
cameraman Alejandro Rocha.

They brush off forewarnings of
the mountain's short temper.

(speaking in foreign langauge)

- [Interpreter]
There were conditions

that could be
considered favorable

to provoking an avalanche,

but you're always sure
that it won't happen.

- [Narrator] As they set
up camp at 19,000 feet,

the signs of impending
disaster are clear.

(tense music)

- These guys are very well aware

that an avalanches occur.

Avalanches occur on
Annapurna all the time.

If you get heavy
snow and warming,

you are going to
have an avalanche.

- [Narrator] Ignoring the risk,

Jesus and Jose
make their ascent.

They're halfway up the
cliff face when Annapurna

springs her trap.

(suspenseful music)

A rippling frozen
surge, 6,500 feet wide

careens down the mountain
at eighty miles per hour.

Alejandro watches in
terror as the snow pack

swallows his friends.

(speaks in foreign language)

Then he realizes
he could be next.

(speaks in foreign language)

- [Interpreter] The cloud was
getting bigger and bigger,

it was like this big white
cloud, a huge heap of snow.

- [Narrator] Helpless
and terrified,

Alejandro retreats
to his only shelter,

waiting for the worst.

[Bleep]

The cameraman braces
against Annapurna's fury

as he pummels the tent
with snow and ice.

(suspenseful music)

[Bleep]

Remarkably, Alejandro
survives the attack.

Immediately, his thoughts turn
to the two climbers outside.

He peeks out, not
knowing what he'll find.

The entire snow face,
all 2,600 feet of it

has plummeted down the mountain

and the Novas brothers
are nowhere in sight.

(speaking in foreign language)

If they're still alive,
it may be only minutes

before Jesus and Jose
suffocate under tons of snow.

(speaking in foreign language)

- [Interpreter] How could
a snow cloud of that size

not bury whoever was on
the face when it hit?

- [Narrator] He scans the cliffs

desperate for any sign of life.

Finally, his camera
catches two tiny figures,

halfway up the slope.

It's Jesus and Jose
clinging to the cliff side.

- [Interpreter] I saw them
and I screamed at them

asking them if they were okay.

(speaking in foreign language)

Since I only saw two tiny
dots, quickly descending.

- [Narrator] Trudging
through waist-deep snow,

the climbers returned to camp.

(speaking in foreign language)

(man laughs)

- [Narrator] Astonished that
Annapurna

has failed to bury
them alive.

- [Interpreter] The avalanche
was a total surprise.

All of a sudden we heard
a crack like a boom.

It was as if something broke.

It was a dissonant bang, boom!

I said an avalanche, quick,
quick, we'll hide over here.

In no time, in just
a matter of seconds,

the avalanche was on top of us.

The cliff protected us from
everything that was falling

from above, forming
something of a shield.

We were under there for
about a minute or so.

It was very difficult to breath.

(speaking in foreign language)

- [Interpreter] I got as
close to the wall as possible

to avoid being hit
by the chunks of ice.

We were only thinking
of not falling down,

of holding on with the ice axes.

- You really have to
admire the quick thinking

of the two climbers.

To see an avalanche bearing
down on them so rapidly

and to be able to take cover
that quickly is really amazing.

- They talk about suffocating
for not being able to breathe,

but that's a heck of a
lot better than being hit

by tons of wet snow.

- [Narrator] All
three mountaineers
are lucky to survive,

a rare instance of Annapurna
missing her targets.

In more recent years,

another disaster on Annapurna
would prove the rarity

of their survival.

In January of 2020,
several South Korean

school teachers went missing.

Their bodies, not discovered
until that spring.

Annapurna with about
one in three climbers

failing to survive the ascent

remains the deadliest
mountain in the world.

- The fatality rate
for Annapurna seems

to be very, very high because

of its great prevalence
of avalanches.

Inclined rock layers that are
easy for snow to slide off of

and climbers going up
glacial valleys funnels

where avalanches
are directed into.

Very hard to avoid
the avalanches.

Very easy to die
on this mountain.

(tense music)

- [Narrator] Each day, several
hundred million metric tons

of ice on the polar ice sheet
are lost perhaps forever.

This alarms scientists because
ice sheets cover nearly

1/10th of the earth's land

and contain about 70%
the planet's fresh water.

- The potential melting
from the big ice sheets

of Greenland and Antarctica,
those are really the gorillas

in the wood shed if you
wanna talk about problems.

Far bigger than
what we would get

from a few glaciers melting.

That's really a key for
civilization in this century,

what's gonna happen
to the ice sheets?

- [Narrator] The same
ominous phenomenon

is taking place
all over the world.

The renowned snows of Mount
Kilimanjaro are disappearing.

The frozen current of
the Andes are drying up.

And the glaciers in Montana's
Glacier National Park

are vanishing.

This full blown retreat
of glaciers is the result

of an overall warming
trend across the globe.

The world's oceans
are heating up.

- The climate system is changing

and it's changing at a rate
that compared to previous

decades and centuries
is quite rapid.

- [Narrator] And warmer
seas mean rising sea levels.

- As water warms, it expands
so warmer water actually

takes up more volume and
increases the sea level as well.

- [Narrator] Scientists are
predicting a rise in sea level

of one to four feet by
the end of the century.

But if the significant portion
of the polar ice caps melt,

it could be much more.

- It's not totally unrealistic

to think that sea level rise
could be maybe up to 10 feet

between now and 2100.

There's a lot of ice
in West Antarctica.

It's grounded below sea level
and it's inherently unstable.

So, we are concerned it
could slip away very rapidly.

And this alone could raise
sea level by 15 feet.

- [Narrator] Low lying coastal
areas could be devastated.

Entire Island nations
in the South Pacific

could be swallowed by the sea.

In Bangladesh, the rice paddies
that feed millions of people

could disappear
under salt water.

Untold numbers of these
people could be displaced

and become climate refugees.

And some of America's
great cities:

Miami, Baltimore,

New York, and Boston

may see their most expensive

waterfront properties
washed away.

Even worse, warmer oceans
will cause more intense

tropical storms and hurricanes.

- A hurricane is a heat engine.

It's a monster that
devours heat and it gets it

from the upper layers of
the ocean and so the warmer

the ocean the more heat for
the hurricane to develop.

- [Narrator] Melting glaciers
could be the first sign

of this impending
environmental catastrophe.

A glacier is a slow moving
river of frozen water,

a tremendous accumulation of
snow compacted by the pressure

of its weight and turn to ice.

- It oozes very, very
slowly under the weight

of its own gravity
and that's the key.

A glacier has to move, in
order to be called a glacier.

- [Narrator] Some of
these frozen rivers of ice

move as fast as
two miles per hour.

During the last Ice Age,

they carved entire
landscapes out of rock.

A glacial system may be
as large as a continent

or as small as a tiny
valley between mountains.

Each year when the snow
falls, new ice is added.

- A healthy glacier is one
that's getting plenty of winter

snow pack and is not melting
too much in the summer,

then it can maintain its
mass or it can even grow.

- [Narrator] These mountain
glaciers have been here

for more than 10,000 years.

Today, scientists are
monitoring their health

on a day-to-day basis.

They predict that every
one of these glaciers

will be gone by the year 2050,

but the life span of
mountain glaciers is short

compared to the rivers
of ice that flow off

the polar ice sheets.

Many of these are more
than 500,000 years old.

It is these polar glaciers
that are even more crucial

to the future of the planet.

Just in terms of mass, the
polar ice caps are astounding.

- Antarctica is not
at the human scale.

It's huge.

If you actually wanna count
all the individual glaciers

in Antarctica, you're
talking about tens

of thousands of glaciers.

- [Narrator]
Difficult to get to,

Antarctica, the
seventh continent,

was not even discovered
until the 18th Century.

Since then, explorers
and scientists

have been trying to
gather information

about the polar ice sheets.

In particular, they wanna
know how quickly the ice caps

are melting, because this
information can tell us how fast

and how much the world's
sea levels will rise.

But the polar regions
have remained elusive.

- You have to realize that
maybe 30, 40 years ago,

we didn't even know where
all the glaciers were,

the important glaciers.

- [Narrator] For decades,
Greenland and Antarctica

proved to be too huge
to accurately survey.

- What we relied on was
putting together hundreds

or thousands of individual
measurements taken

in the field by
individual scientists

going and visiting a polar
ice cap and taking samples.

- [Narrator] The complete
picture of the polar regions

and all their
glaciers has remained

an enormous jigsaw puzzle.

- There's no way from fieldwork
alone you could say anything

about the entire ice
sheet with certainty

and with precision.

- [Narrator] Now scientists
say seeing the ice sheets

in their entirety may
be a matter of survival

for future generations.

- We really need to
look at all of them,

detect the areas where the
changes are taking place

and keep an open mind that
it may not be just one

or two glaciers
that are changing,

but it could be a
whole coastal range

of several thousand kilometers

which is changing
at the same time.

- [Narrator] These changes
in the polar ice sheets

and glaciers could
spell disaster.

And what these scientists
discovered could have

a life or death impact
on millions of people

around the world.

st spectacular

photographic evidence
of nature's fury,

it is by far not the only
hazard faced by those

sitting below tons of
unstable ice and snow.

(tense music)

Namestovo, Slovakia.

It's a thrilling day for
a 150 of the country's

junior hockey players.

They get to meet their idol:

13-year NHL veteran
Richard Zednik.

The Slovak native survived
a brush with death in 2008,

when a player's
skate cut his neck.

He never expected that a
casual Sunday training session

with his home country's
up and coming stars

could also turn deadly.

But just over their heads,

mother nature is putting
the finishing touches

on a sinister plot.

- [Narrator] In Northern Europe,

there's a lot of
heavy winter weather.

Snow, ice, winter storms,

seemingly everyday weather
can lead to big problems.

- Snow might not seem that
dangerous when it falls,

but to a very large,
very wide flat roof,

it can be very destructive.

- [Narrator] As the young
athletes practice their moves

on the ice, ominous noises
from above get their attention.

Suddenly, the roof
cracks open and buckles,

threatening to kill
everyone underneath.

Richard and the other adults
try to hustle the children

out of harm's way before
they're crushed to death.

They flee the collapsing
arena through passageways

along the perimeter that
remained free of rubble so far,

but everyone knows the rest of
the roof might easily cave in

before they find the exit.

- The ceiling
essentially unzipped.

This was a large Quonset hut.

A Quonset hut is a steel arch.

And the one problem
we see with arches

is drain drifting snow,

where all the snow will drift
to one side of the arch.

And that unbalanced load
can cause an arch to buckle.

- These kinds of buildings
are always a challenge.

How do you cover a large
area with enough strength

to stand up to a stress.

And here they failed the
test, the roof collapsed.

- [Narrator] The near
fatal disaster is anything

but a triumph homecoming
for Richard Zednik.

(speaks in foreign language)

- [Interpreter] It
was complete horror

when it started to collapse.

Imagine suddenly a ceiling
falling straight on your head.

I looked around and
saw people in panic.

In two or three seconds, the
ceiling was on the floor.

- Given the number of people
that were in this building

and out on the ice at
the time the ceiling

began to collapse,

it's remarkable that
everybody survived.

And it would have
been very deadly

for anybody who
had been under it.

- [Narrator] For centuries,
America's early geologists

were puzzled by mysterious
marks etched into the bedrock

of much of North America,

and by lonely mountain rock

randomly scattered
across the land.

(thunder crashing)

Then in 1847, a newly-appointed
Harvard university professor

came up with a radical new idea.

Geologist Louis Agassiz

compared North America's
landscape and rocks

with the geology of
mountain glaciers

in his native Switzerland.

And he built on theories
he had developed

in this Swiss Alps a decade
earlier to declare that

North America had once
been buried deep under ice.

Agassiz's work at Harvard made
him world-famous in his day.

But the final proof
of his Ice Age theory

had to wait until the 1950s,

when new evidence
came from the seabed

of the Atlantic Ocean.

That evidence is still
stored to this day

in this refrigerated
laboratory at Miami University.

These thousands of plastic
tubes offer scientists

a unique window to look back
at what the weather was like

on the ancient Earth.

- These records that you
see in this room here

basically are the primary
information we have now

about the climate
changes we have had

over the last two million years.

So these are really
starting points

that open people's
eyes about changes

which occurred during
glacial periods.

- [Narrator] The mud
cores were collected

by oceanographer
Cesare Emiliani.

The deeper he drilled, the
further back in time he went

and the older the sample
he pulled to the surface.

- These are cores
of deep sea mud.

And within the mud
are small organisms,

which record the
temperature and the salinity

and the other conditions
which were prevalent

when that organism lived.

- Those tiny undersea creatures
are called formanifera.

Their chemical makeup varies,

depending on the
temperature of the water

in which they grow.

So the sea bugs in
different layers of mud

act as tiny thermometers,

recording how hot or
cold the Earth was

at different times in its past.

(haunting music)

They reveal that just over
two million years ago,

the average annual temperature
across the lower 48 states

was around 56
degrees Fahrenheit,

about three degrees
warmer than it is today.

Then, the temperature regularly
started crashing below zero

and staying there
month after month.

(dramatic music)

Huge changes happening in
what, in geological terms,

was astonishing speed.

Within 10,000 years,

the year-round average
temperature bottomed out

at just 26 degrees Fahrenheit,

about the same as the average
winter temperature in Chicago.

Even today, scientists
are uncertain

what caused the temperature
to drop so quickly.

Variations in the Earth's orbit,

a change and the
tilt of its axis,

and even the creation of
the Himalayan mountain range

are all prime suspects.

But one thing is certain.

With subzero temperatures
all year round,

snow never melted.

A major storm can drop more
than 40 million tons of snow.

The ever-increasing weight
of snow compacted down

into thick layers of solid ice.

America's Ice Age had begun.

The ice sheets, which built
up two million years ago,

began to move, flowing
as huge glaciers

across the northern U.S.

- Some of the very large
rocks can be literally

frozen on and cut off from
the rock that they came from,

and just put it right into
glacier and moved that distance.

Hundreds of miles
in the glacier,

like a conveyor belt, out
to where we finally find it

on the landscape or in
an outcrop like this.

- [Narrator] The
investigator's next challenge

is finding out just
how far the ice flowed,

and for that task, they
are taking to the air.

In the early morning light,

Brown spots a
mysterious small hill

standing out from the
flat Illinois plain.

Stripped of its
camouflage layer of trees,

the shape of the
hill tells Brown

the secrets of its creation.

- This gently rolling landscape
extends for about 400 miles.

We look at the land forms
and how they're shaped,

And so we can use
that to unravel

the history of the Ice Age.

(lively music)

- [Narrator] The landform
Brown is studying

is a mound of rubble that
geologists call a moraine.

It is an accumulation
of debris that a glacier

has plucked up from the
Earth, dragged along,

and dumped at the front edge.

This hill marks the
spot where the glacier

finally stopped
flowing southward.

Geologists all over
the U.S have recorded

the positions of
other moraine hills,

helping them map out
precisely how far

North America's
ice sheets spread.

Nearly 2/3 of the North
American continent

was buried under ice,

but the frozen chaos
did not stop there.

The challenge now facing
geologists is figuring out

how ice created some of
modern North America's

most famous features.

Coming up.

- [Man] It's like a
fricking war zone.

- It felt like at one point we
were under assault.

(dramatic music)

- [Narrator] Two million
years ago, temperatures fell,

and massive ice sheets
spread out as glaciers

across much of North America.

Geologists set out to discover
what the moving ice did

to the underlying land.

Everywhere the ice had flowed,

investigators discovered
the same puzzling feature.

Lines of stones, all laid
out the same particular way.

- Really good example
of pavement of stones,

this concentration of
small rocks and cobbles

that are collected
here in a line.

It's just one, one stone
or two stones thick.

- [Narrator] Scientists realized
that the stone pavements

must have been laid down
at the base of a glacier.

And even the toughest rocks
had scratches and grooves

carved into their surface.

- [Steve] Glacier carries
along other fragments of rock.

And as it's doing so
it scratches, polishes,

creates grooves in the
rock called striations.

- [Narrator] Those scratches
offered vital clues

to help uncover the history of

how the Ice Age changed America.

- So by lining my
compass parallel to

the striations on this rock,

the compass tells me
that the ice is flowing

from about the northeast,

from this direction
to this direction.

- [Narrator] But other
scratches on rocks

found all over the
northern parts of the U.S.

run in puzzlingly
different directions.

These ice-scraped rocks
in New York's Central Park

show scratches made by a glacier

that arrived from the northwest.

There's only one explanation
of the different ways

in which the ice
appears to have moved.

The scratches were not all
made by a single ice sheet

as first thought, but
by many different ones.

- This phenomenon of
advance and retreat,

the changing of that
landscape, happened many times.

Not just once, but many times.

- [Narrator] Everywhere
the ice flowed,

it marked the underlying blocks.

- The ice changed.

The existing conditions on
the landscape was changed.

The motion of the glacial debris

changed the whole
way these areas look.

- [Narrator] Grinding
over the landscape

at speeds of around
two feet per day,

the massive glaciers diverted
the course of ancient rivers.

Even the mighty Mississippi
was no match for the ice.

- It moved the position
of the Mississippi River.

The Mississippi
River used to flow

through the middle of Illinois.

- [Narrator] A glacier
advanced across the state

and created an ice dam across
the course of the old river.

A huge lake grew at
the edge of the ice,

eventually over-spilled,
and cut a new river channel

80 miles to the west.

(stately music)

The same course that
it follows to this day.

And when the ice
sheets melted away,

their impact on North
America was almost as great.

They produced immense
floods of water,

which all had to
drain away somewhere.

- It formed a completely
new landscape,

with a new river
mouth, a new channel,

completely rearranging
the character

of the existing landscape.

- [Narrator] Where rocks were
soft, or weakened by faults,

the glaciers had carved out
huge basins in the landscape.

When the floods came,

these depressions rapidly
filled up with water.

- Every natural lake here in
Indiana, Illinois, Wisconsin,

were all created by glaciers.

- The biggest
ice-scoured basins became

what we now call
the Great Lakes.

These water-filled craters in
the North American landscape

are nearly five and a half
thousand cubic miles in size.

The water they hold t
could drown the whole

of New York State to a
depth of more than 600 feet.

But even that is
just a tiny fraction

of the total flood
unleashed as retreating ice

poured out nearly 39,000
cubic miles of water.

The flood rushed down
Niagara Escarpment,

at the rate of 42
million gallons a minute,

one and a half Olympic-sized
swimming pools every second.

And that cut a gorge
seven miles long

and 180 feet deep
through solid rock.

The Ice Age had created one of

the modern wonders of
the world, Niagara Falls.

(haunting music)

The investigators' next
challenge was figuring out

why the ice advanced
and retreated so often.

It wasn't until the mid 1960s

that the first real
clues were discovered.

The U.S. military
was building bases

in some of the Earth's
most remote locations.

- [Newsreel Narrator] This is an
ideal arctic labratory,

permanently frozen
under a polar ice cap

which covers all but a few
costal areas of the island.

Geologists realized the
cores of ice being extracted

by hollow drills held a
unique historical record.

(lively music)

Those cores and many
others extracted since

are housed in a laboratory
in Denver, Colorado.

- We're in the Fort
Knox of paleoclimate.

What you see in
these tubes is gold

in terms of what we
know about climate

and what we've learned about
climate over the last 50 years.

- [Narrator] These tubes contain

three-foot-long plugs of ice,

each dug out from layer after
layer of compacted snow.

But it is what is
trapped inside the ice

that most fascinates
the scientists.

As each year's snow
falls onto the last,

it builds up and
moves packed layers

that trap air between
the snowflakes.

- Ice cores are the
only archive we have,

really good archive we
have, of past atmosphere.

In an ice core, you
can see tiny bubbles,

and those bubbles are
air, unadulterated air

from as much as a hundred
thousand to a million years ago.

- [Narrator] The deeper the
bubble, the older the air.

- It contains not only
a temperature signal,

but it contains dust signals.

It tells about
atmospheric circulation.

It contains a record
of the atmosphere,

and specifically the
greenhouse gases.

- [Narrator] Each ice
layer corresponds with

the precise time
in Earth's history

when its snow first fell.

So by analyzing the
bubbles from any one layer,

scientists can figure out what
Earth's atmosphere was like

at any point in the past.

- Over the last
million years or so,

we see fairly regular pacing
of major, major glaciations,

roughly one every 100,000 years.

- [Narrator] Some theories
suggest those colder spells

coincide with variations in

the Earth's orbit
around the sun.

But that's not the only
thing the ice cores revealed.

The cores that White has
been studying suggest

that the longer the ice age
went on, the worse it became.

- Somewhere around
400,000 years ago,

we went from a period that
had lesser glaciations,

if you will, to ones
that were very, very big.

- [Narrator] But new
clues suggests that

the awesome impact of America's
Ice Age didn't stop there.

Coming up.

- You've got the
snowfall moving down

the side of a
steep-sloped mountain

at 60 to 80 miles per hour.

No one can run that fast.

music)

- [Narrator] From the modern
day remnants of glaciers past

to their deposits
comes the question,

how did they get there?

What forces were in play that
could carve great crevices

and deep lines seen
across North America?

The answers lie
right at our feet,

in some of the most recognizable
outdoor spaces on Earth.

The first clue came in New
York State, on Bear Mountain.

- No one knows
for sure how thick

the ice sheet was that
came from the northwest.

But right now, we're standing
at the top of Bear Mountain,

about 1,280 feet
above sea level.

What we're looking at here
are a series of chatter marks.

These are features
of glacial erosion,

and they're produced by
large blocks of solid rock

embedded in the base of
a very thick glacier.

Those boulders were hinged
on this bedrock surface,

plucking pieces of rock
off as the glacial ice

moved through the area.

- Charles Merguerian's
mountaintop discovery

shows how thick the
advancing ice must have been.

- Most people think that
this glacial ice sheet

was about a mile thick or more.

- [Narrator] The marks
are clear evidence that

the New York ice sheet
must have towered

about four times higher than
the Empire State Building.

(dramatic music)

Figures like this have
enabled Merguerian to estimate

the total amount of ice
that buried North America.

It's a staggering 17
million cubic miles of ice.

- Imagine this block of ice,
it's about six inches thick,

being the ice sheet that
covered North America

during the last glaciation.

You would need several
billion of these,

maybe a hundred billion.

It's a number almost
too big to imagine.

- [Narrator] This block
of ice weighs 27 pounds

and is just half a
cubic foot in size.

But there were 17 million
cubic miles of ice

covering America.

When scientists calculated
the total weight of the ice,

it was an almost
incomprehensively large figure,

68,000 trillion tons.

Unsurprisingly, such
a vast weight of ice

did not just affect America.

It distorted the
shape of the planet.

- I've got a beach ball
here that has a depiction

of the whole Earth, and
every continent on it.

And right here is the
outline of North America.

And during the Ice Age,

snow started to
accumulate in Canada.

And as that ice thickened,

it started to flow from the
centers of snow accumulation

southward into North America,

reaching its maximum extent
right here in Illinois.

And when it did that,

this mass of ice
depressed the continent.

(energetic music)

- [Narrator] Earth's
solid crust sits on top of

a layer that scientists
call the mantle,

semi-molten rock
which behaves a little

like hot, sticky plastic.

The weight of the
vast plains of ice

pushed down inland
areas, and simultaneously

made parts of the coastline
bulge up from the sea.

But investigators also found
that in some other areas,

the ice altered the outline
of America's coasts,

the borders of the
sea that define

the continent we see today.

A vital clue came
in downtown Miami

in the unlikely setting
of a municipal courthouse.

- We're here in front of
this impressive building

built in the early 1900s
because of the materials

used to face its surface.

These stones are constructed
of fossilized coral reefs.

And if you know what
you're looking at,

it can actually tell you quite
a bit about Florida's past

and maybe its future.

(lively music)

- [Narrator] The coral
stone is made from

the hard calcium
carbon and skeletons

of tiny sea creatures,

animals that only grow
in very shallow water.

But this courthouse
stone was quarried

out of an ancient coral
reef that now lies

a mile from the present-day
ocean and way above sea level.

- I'm standing here about five
or six feet above sea level

and walking alongside
this rock face,

which is about six feet tall.

The interesting thing
about this rock face,

it's actually composed
of fossilized corals.

And the fact that we're
standing here today

amongst these fossil corals
tells us that in the past,

we would have been under 10
or 15 feet of water right now.

- [Narrator] The coral
stones have been dated

to around 130,000 years ago,

which means the sea
level around Miami

must then have been
far higher than today.

As experts tried to figure
out why the sea level

was so high then,
new evidence emerged

about Florida's coral reefs,

and the mystery
deepened even further.

(lively music)

Divers off the coast of
Miami found a coral reef

now submerged 450
feet under the water.

These corals grew
just 25,000 years ago,

and because a reef like this
only forms in shallow water,

the scientists realized
that the sea level back then

must have been far
lower than it is today.

And that means the
coastline would have been

in a completely
different location.

- Right now we're about two
miles offshore Fort Lauderdale,

on the edge of the Gulf Stream.

But 20, 25,000 years
ago, at the time of

sea level low stand,
we would be sitting

right next to a beach here.

We'd been looking
where we see today,

the ocean and the high
rises in the back,

we'd be looking
towards a sandy beach

in front of a gently
rolling hillside.

- [Narrator] Investigators
studying the coral records

figured out that the up and
down sea levels would repeatly

have altered the entire
shape of America.

- If you look at the
outline of North America,

the outline that I learned
to draw in elementary school,

if we were living years ago,

I would draw
Florida differently.

- [Narrator] 25,000 years
ago, when sea levels were low,

Florida was triple
the size it is today

because more land
was out of the water.

Geologists realized that
the changes in sea level

around the coast were
directly related to

the different levels
of ice on land.

That discovery was the
key to understanding

what the Ice Age had done.

(dramatic music)

Water evaporated from the oceans

and condensed in the
atmosphere to form snow.

But in the colder times,

that snow built up as
ice sheets on the land,

and with so much of the world's

total water supply
locked up as ice,

the oceans simply
ran short of water,

and the sea levels fell.

- When the Earth is cold,
there's more ice on the land.

And sea level is
lower because of that.

When the Earth is warm,

there's less ice on the
land and sea level's higher.

And that makes sense
because when that ice,

when it melts off the land,
has got to go in the ocean.

- [Narrator] But it's
not just enormous

city-sized ice shelves
that can rock our world.

Sometimes it's much
smaller chunks of ice

that can do the most damage,
especially when they're

raining down from
above like cannonfire.

(ominous music)

Oklahoma.

Known far and wide as
the heartland of the U.S.

But this state has another
quality that sets it apart.

And this one can kill.

- Where did the
big hailstorms hit?

The epicenter is the
state of Oklahoma.

They get more than 25 of
these big hailstorms per year.

- Hailstorms tend to happen
in locations where you have

hot, moist air colliding with
relatively cool, dry air.

It's these forces that cause
the warm, moist air to rise up

and start the cycle that leads
to a thunderstorm and hail.

And Oklahoma, unfortunately,

is exactly this
kind of location.

- These stones can be moving
at 100 miles per hour.

If a hundred-mile-per-hour
chunk of ice

hits you in the head, it
can very easily kill you.

- [Man] No!

- [Narrator] A severe
thunderstorm unleashes

a hellish assault on
the state capital.

- Oh my god.
- That's insane!

- This particular
hailstorm was actually

a warm front that
was moving through

that caused a lot of
instability in the atmosphere.

- [Narrator] Chunks of
ice blast the entire city.

- [Man] Holy crap!

- This hailstorm reminded me
of a Civil War battlefield

with cannonballs
landing all around you.

- [Man] Baseball-size hail.

- When I see baseball
and softball-size hail,

that tells me this is an
enormously

powerful thunderstorm.

- Softball-sized hail
is relatively rare.

'Cause when you think about it,

here's a drop of rain
that's frozen into ice.

Ice makes it heavier.

It wants to fall, but that
means updrafts of wind

have to pick it
up and hold it up.

- Then what happens is
the hailstones fall down

and melt slightly and are
coated with more water.

Then they're carried up
again by more updrafts

to be coated by an
additional layer of ice.

At that point,
they start to fall.

- [Bonnie] Oh my god!

- [Narrator] College
student Bonnie Tibbs

is home visiting family

when their house is
suddenly under siege.

- Oh my god, it's
hitting the window!

This hail is loud and it's big.

and it's slamming up
against our house.

It was like rocks were
being pelted at our house.

I literally moved away
from the kitchen window

and moments later, large shards
of glass were flying out.

So that's when I screamed
to get in the closet.

- [Narrator] Across town,
Mac Maddox and his fiancee

suddenly find their
homes under fire by ice.

It felt like at one point
we were under assault.

We hear the skylights
getting busted out

and shards of glass
going everywhere.

- The house is
literally shaking.

It feels like there was
an army outside just

taking machine guns through
the entire apartment.

I started to worry about
even our lives at this point.

- [Narrator] The storm
intensifies and Mac realizes

he's under a full-force
frozen assault.

Windows were getting busted out.

Blinds were getting ripped off
of the windows on the inside.

There were shards of siding
that was getting blown off.

It felt like we were in
the middle of a war zone.

- [Narrator] 20 minutes later.

- [Narrator] The Tibbs
family emerges from hiding.

- [Narrator] The onslaught
shatters windows and skylights.

- [Bonnie] Oh my god!

- [Narrator] Allowing
pounding ice to destroy

the family's belongings.

- After the skylights
are completely gone,

and you've got these six
giant holes in your house,

it continued to rain.

It actually came onto
the rugs and furniture,

the walls, everything.

- It's crazy to
think that your day

could start off
absolutely normal.

This is the aftermath.

Windshield's
shattered on my car.

And just literally matter
of minutes could turn into,

you know, your whole
livelihood getting destroyed.

- Hail like this, that
destroys car windows,

puts big dents in cars.

If a person happened
to be unlucky enough

to be outside and
have no shelter,

it could seriously
injure or even kill them.

(ominous music)

To see actually
literal baseballs

and golf balls
flying from the sky

and totally tearing
everything apart,

I don't know if I'll
ever see anything

like that again in my life.

- Mother nature got us good.

We always thought we
could outsmart her,

or she wasn't gonna affect us.

It's in my room!

We know that we can be affected

and that we can't outrun her.

- [Mac] It's Armageddon!

rs melt,

the area of white
reflective surface shrinks,

replaced by Earth or ocean,

both dark surfaces
that absorb more heat,

which in turn
accelerates meltdown.

This is what scientists
call a feedback effect.

(energetic music)

In the last four decades,

there's been a significant
loss of glaciers

in Montana's Glacier
National Park.

- Since the '70s, we've had
pretty much a very rapid

and full-scale disappearance
of the glaciers.

- [Narrator] Ecologist Dan Fagre

has been monitoring their
demise for many years.

- Well, we use several ways
of monitoring the glaciers.

The first and most obvious
one is that we take pictures,

and these can be pictures
from a point in the landscape,

so you're looking at
it from the side and

you can just look at the
visual changes year by year.

- [Narrator] Sequential
photos taken decades apart

show how specific glaciers
have shrunk in size.

- I can see with my own eyes

how much that
glacier's disappeared.

And it's a little
bit of a compelling

and alarming kind of view
because you think about glaciers

as being, you know, a steady
presence on a landscape.

And to see it disappearing
this quickly means

that we are going through
some very, very dynamic times.

- [Narrator] Here,
Fagre is photographing

Salamander Glacier, which
has been losing mass rapidly.

For glaciologists, the surface
area is not the only factor

that's important in
determining a glacier's health.

- It's also how thick it
is or how much total mass.

And for that, we do a lot of
ground measurements as well.

And we can go on the glacier
with global positioning systems

and get both the
area and the height.

- [Narrator] The prognosis
for Glacier National Park

is dire.

- Based on the best measurements
that we have to date,

it looks like the year 2030
is when most of the glaciers,

if not all the glaciers,
will be completely gone.

- [Narrator] A similar
fate is predicted

for glaciers all over the world.

- Almost all of
the world's alpine,

mountain, or valley
glaciers have been receding.

What's happening in
Glacier National Park

is basically going on globally.

We're seeing that
these mountains

are being transformed
by climate changes.

- [Narrator] Melting glaciers
have long posed a threat

to local communities.

Like many high mountain
areas, the glaciers of Peru

were once feared for the
avalanches they unleashed.

Sometimes icy mountains hide
their true destructive nature

behind picturesque
scenes of winter wonder,

spectacular beauty, secretly
poised to destroy whatever

and whomever is in its path.

(ominous music)

Odda, Norway.

Set at the base of the
Klungersetskreda Mountain,

Odda is the picturesque home

to approximately
7,000 residents.

- You've got the elevation,

you've got the topography,
you've got the mountains.

You've got lots and
lots of snowfall.

- [Narrator] These majestic
peaks have stood guard over Odda

for hundreds of years,

but locals don't know that
the mountains themselves

are poised to attack.

(ominous music)

A loud rumble erupts as an
icy juggernaut races downhill.

- This avalanche begins
relatively small,

but very rapidly gains force.

- [Narrator] Residents
know they're in trouble

when the Earth itself seems
to unleash a mighty roar.

(rumbling)

- It's almost like
a big jumbo jet

coming down the mountainside.

- [Narrator] Police
officer Johnny Helle

is stunned by what he
sees out his window.

- I was thinking it
will be a big disaster.

- [Narrator] As the
mountain shed seven stories

of snow, ice, and rocks,

Eivind Kopperdal videotapes
from his home across the fjord.

- This avalanche came
like a big waterfall.

There was a rumbling
and a very ugly noise.

- This event is
triggered because of

an enormous amount of snow
leading up to the event.

And then there was a warmup.

- This avalanche was
a lot of wet snow,

which means it's heavier
and has more mass.

- The snow stored
at a high elevation

has tremendous potential energy.

Once it breaks loose and
starts moving downslope,

that potential energy is
converted to kinetic energy,

which creates tremendous
momentum and power.

- It's pushing the
air out ahead of it.

So you have gale-force winds
coming down this mountain.

- [Narrator] The onslaught wipes
out everything in its path,

including trees that
have stood for decades.

- One of the reasons why
this avalanche is so deadly

is the debris that it's
picked up along the way.

A rock or a tree or a boulder
has much more momentum

and much more force than snow.

- [Narrator] Seconds later,

the avalanche
takes aim at homes,

and now lives are on the line.

- In an avalanche, your chances
of survival are very low.

You've got the snowfall
moving down the side

of a steep-sloped mountain
at 60 to 80 miles per hour.

No one can run that fast.

- The avalanche get bigger and
bigger and wider and wider,

and my God, I thought,
it's going to the houses.

- I was sure that this
would kill a lot of people.

- [Narrator] The snow
slide swallows a house

where a family is just
sitting down to breakfast.

- Initially it's just
knocked off its foundation.

- [Narrator] But the
three people inside

don't stand a chance as
the 100-year-old structure

topples over.

- The house just
disappeared in the snow.

I got a real bad, bad feeling.

- [Narrator] The
70-foot wall of ice

continues down the
slope and threatens

another home near the shoreline.

But the house is spared.

- We see two houses
attacked by the avalanche.

The one on the left is
being hit by brown snow,

that's snow carrying rocks
and debris against that house.

The house being hit
by the white snow

without the rocks survives.

- [Narrator] Then, after
six terrifying minutes,

an eerie silence.

- This was a very
special quietness because

I felt like everything
stopped, no sound at all.

- [Narrator] Helle
fears the worst,

Since the snowpack
is like cement.

- I had to go out, see how
many people was killed,

because I was 100%
certain that houses

had been smashed
by this avalanche.

- Unfortunately,
rescue in an avalanche

can be very, very difficult.

Even if you survive
the crushing power

of the avalanche itself,

it will be very, very
difficult to find you.

(ominous music)

- That's where
somebody was killed.

There were three
people in that house.

Two of them escaped
into the basement.

The third person was in a
wood-frame portion of the house

above the basement,

and they were killed when
the house was crushed.

- [Narrator] Since
that fateful morning,

barriers have been built to
divert any future avalanches,

but the villagers know that
what's up on the mountain

is truly a higher power.

- In the path of an avalanche,

you don't have any
really good options.

- You are mostly helpless.

(dramatic music)

- I feel very small compared
to what nature can do.

can
significantly impact

rising sea levels,
but in Iceland,

that meltdown isn't
only environmental.

It can be explosive.

In fact, the evidence
is mounting that Iceland

has the potential to be

the most lethal
island on the planet.

A fearsome volcanic
force lies beneath it,

creating powerful volcanoes
capable of generating

gigantic lava floes and
altering global climates.

(haunting music)

Yet many of Iceland's
are covered in glaciers.

Fire and ice are held
in a delicate balance.

Scientists fear if this
balance were tipped

in the volcanoes' favor, Iceland
could become even deadlier.

If the remaining
ice were to melt,

what effect would it have

on the activity of
Iceland's volcanoes?

The first clue in
the investigation

lies in these innocuous-looking
piles of rock and rubble.

They're found all over Iceland,

and yet these rocks don't
come from a volcano.

They're moraines,
the geological term

for rock piles deposited
at the mouth of a glacier.

These deposits are evidence
the glaciers are shrinking.

Year by year the
glacier has melted

and retreated back
up the valley,

leaving a moraine
like this behind.

Dr. Roberts has studied
the Vatnajokull glacier

for many years and has
noticed this dramatic trend.

- The glacier has retreated
at a remarkable rate.

Since I've been
visiting the area

I've seen tremendous changes.

The ice has retreated annually

at a rate of about
200 feet per year.

This lake over here used
to be filled with ice.

I've seen the ice
progressively melt.

This moraine has formed.

This whole valley has
become almost bare.

Maybe in the next 20 years,

this whole glacier
will disappear

and a lake will
form in the Valley.

- [Narrator] Iceland's
glaciers are melting

at an unprecedented rate.

With an increasing amount
of Iceland's ice caps

melting in the last 50 years,

the question that scientists
are keen to understand

is what effect this
rapid melting will have

on volcanoes that lie beneath.

The only other time
that glaciers

have melted this quickly

is when Iceland came
out of the last Ice Age.

But what can past events
tell us about the future?

Geologists professor
Bill McGuire

is investigating how
volcanic activity changed

at the end of the last Ice Age.

And he's unearthed some
surprising results.

- Around about 11
to 12,000 years ago,

you started to see quite
rapid melting of glaciers

in Iceland and elsewhere,

and that triggered a
recognizable increase

in volcanic activity
because you were removing

this large mass of ice
very, very quickly.

- [Narrator] The
rapid melting of ice

kickstarts volcanic
eruptions beneath.

- Volcanic eruptions
are triggered by the

gas in the magma,

which expands to form bubbles

and the bubbles
drive the eruption.

It's rather like
taking the cork out of

a bottle of champagne.

Now, if you have a very heavy
weight on top of a volcano,

if there's heavy
mass of water or ice,

that can help suppress
eruptive activity.

- [Narrator] But when
ice melts quickly,

this downward pressure
is suddenly released.

And that's when
the trouble starts.

- As the ice melts,

so the pressure on the
magma underneath is reduced,

the gas in the magma
can form bubbles.

They can coalesce and they
can eventually drive the magma

upwards towards the
surface and trigger either

explosive eruptions
or effusions of lava

that can spread out
over huge distances.

- [Narrator] Imagining
an ice-free Iceland

isn't that far-fetched.

In fact, it's a future
Iceland's leaders

are taking very seriously,

not only for its potentially
far-reaching economic impact,

but for what is likely
explosive geological activity.

- The question is when.

These are things that
we have to think about

and try to prepare
ourselves to deal with

if they happen in our lifetime.

- [Narrator] Coming up.

- The one major difficulty
we have, the flow of glaciers

is mostly caused by what's
happening at the bottom.

And the bottom is the
part that we don't see.

glaciers serve as vital
reservoirs for fresh water,

providing 50% of the water
nearby populations need.

- When mountain
glaciers disappear,

there can be some real direct
consequences for human beings.

Case in point is some of
these valleys in the Himalayas

it is the glaciers,

particularly at the
end of the dry season,

providing the drinking
water for people.

So when those
glaciers disappear,

those people will have to
find alternate water supplies,

or basically have to move.

- [Narrator] In the
Western United States,

our dependence on glacial
ice and snow reservoirs

is just as great.

- It's about 87% of the
water that Americans

in the West have to use.

So mountains are
very, very critical

in providing that water.

- [Narrator] A reduction
in drinking water

is only one of the problems
caused by melting glaciers.

Equally as troubling is
what a meltdown of ice

in the polar regions will
do to sea levels worldwide.

And the melting is occurring
faster than anyone predicted.

In 2000, scientists
were stunned by changes

at Antarctica's Ross Ice Shelf.

The ice shelves act as
buttresses for the glaciers,

holding them back from the sea.

Over the course of two weeks,
a 4,247-square-mile fragment,

an area the size of
the island of Jamaica,

shattered and separated
from the continent.

Three trillion tons of ice,

one of the world's
largest recorded icebergs,

drifted out to sea.

(ominous music)

- We're talking about
several degrees warming,

over the last century,
which is a huge number.

The ocean has been very
hot and cold, and today,

we just have no idea what's
going on with the ocean.

- [Narrator] But it's
difficult to determine

how fast the
glaciers are melting.

- The one major
difficulty we have,

the flow of glaciers
is mostly cut short

by what's happening
at the bottom.

And the bottom is the
part that we don't see.

The changes that we're
observing in the ice sheets

are more rapid, and larger than
what is predicted by models.

I think in the
most extreme case,

a lot of Greenland
would be removed,

and a lot of west Antarctica.

Then you could raise sea
level 10 times more than that.

30 feet.

- [Narrator] A 30-foot rise
means that many low-lying areas,

such as large portions of
Florida, would be submerged.

Today satellites are
the most important tool

that scientists have for
monitoring what's happening

to the oceans and
the ice sheets.

- To see the whole ocean,

you have to do it from far away,

and you really have
to do it from space.

- Satellites are able
to do this for us

because they're
observing 24 hours a day,

seven days a week, 365 days
a year, for years at a time.

- [Narrator] Scientists
estimate about 200 billion

metric tons of ice
melt away every year.

For those who study
these satellite signals,

it's an alarming picture.

Rising oceans will swallow
farmland, towns, and cities.

But unlike floods of the past,

once the waters have been
unleashed, they will not recede.

- Most places in the world,

people live within about
100 miles of the ocean.

It doesn't matter where we are.

The population lives
close to the sea.

In China and Japan and Europe,
America, Africa, everywhere,

and those are the places
that are most vulnerable

to climate disruption.

They're the ones that are
gonna be hit the hardest.

- [Narrator] One catastrophe
slams into another,

like the pinball
hitting its target

and ricocheting to the next.

- And so we envision
a situation where

you have the West coping
with its water problems,

the hurricane zone
coping with hurricanes,

the Northeast coping,
not just with windstorms,

but with hailstorms
and ice storms,

which will also impose a burden.

The Midwest, we're looking
for swarms of tornadoes,

which causes an enormous
amount of insurable damage.

- [Narrator] So much
uncertainty in a world

plagued with an
ever-changing climate.

Change is indeed happening,

and more quickly
than we might like.

If we fail to act on
these things we can change

and prepare for what we can't,

we are doomed to living
on a radically different

and hostile planet.

(ominous music)

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