All language subtitles for Episode 07 On Thin Ice

This white wilderness,
this emptiness, is the North Pole.

I'm standing in the middle
of a frozen ocean.

Beneath my feet and for
over 500 miles in every direction,

there are several metres of ice.

But something significant is
likely to happen here,

at the North Pole, soon.

Chances are that some time,
within the next few decades,

perhaps even as soon as 2020,
there will be open water here

for the first time
in human recorded history.

The Arctic
and Antarctic are changing.

Enormous masses of ice that have been
frozen for thousands of years

are breaking apart and melting away.

Ice scientists are going to
extremes to find out exactly

what's going on.

For them, these are exciting times.

But the transformation that's being
seen here will be felt

far beyond the polar wilderness.

In this programme,

I'll be trying to understand what
these changes mean, not just to the

wildlife and people that live around
the Poles, but for the whole planet.

I'm starting my journey in the
Arctic, the far north of our planet.

It's still very cold
outside by most people's standards,

but the Arctic has been warming fast,

twice as fast as the rest
of our planet.

My first mission is to find out
what effect

that's having on the animals.

Although first, we have to find them.

It's April in Svalbard.

We are 1,000 miles
north of the Arctic Circle,

in search of the region's
top predator.

We need to travel away from the land
and out over the frozen sea.

There's some tracks
right beneath us.

Over there.

I'm with a Norwegian team,

which is giving the polar bears of
Svalbard their yearly health check.

She's under us now.

I'll come round for a clean shot.

The team works together to
give an anaesthetic injection

from a dart gun without hurting
the bear.

It takes tremendous skill.

You've got it.

I'll just back off
until she's asleep.

Nobody likes to see a magnificent

animal like a polar bear lolling
about unconscious on the ice,

but it's only by darting them

in this way and keeping check on them

year after year,
that we can be sure we know

what is happening to them and the
population of polar bears as a whole.

Over the last 30 years,
many teams have been seeing

the condition of their local bears
deteriorate.

Although not every bear is suffering.

How much? 96, there.

And 102 here, so that's 197, yeah.

Is that good?

It's not too bad,
it's a bit above average.

So she's a bear in a good condition
for Svalbard.

The trouble is that if this was
underweight, she would be in trouble.

Not only from her own point of view,
but from the point of her cubs,

because an underweight female
gives birth to underweight cubs

and underweight cubs have a great
problem of surviving

their difficult first year
in these circumstances.

It can be minus 40 degrees Centigrade
when polar bear cubs emerge

at the start of the Arctic spring,

from their dens where they were born.

This mother hasn't
eaten for half a year.

She and her cubs need to fatten up
fast over the next few months and

their chances of survival depend on
what's happening beneath their feet.

These polar bears aren't walking
on land.

They're roaming across the frozen
surface of the sea.

And the bear's food lives
under the ice.

Ringed seals are hunted
by polar bears.

In fact, in some parts,
polar bears eat almost nothing else.

So, it's very understandable that
this mother ringed seal...

who's looking at me now,
should be a little apprehensive.

That pup of hers is only about
three or four days old...

and the pup won't be able to swim
for another two or three days.

Seals have good reason to be
nervous around their holes.

They need the holes to breathe
when the sea is frozen,

but this makes them easy to find.

Polar bears can sniff out seal holes,
even if they're covered in snow.

Spring is the best hunting season.

This mother's found a food store
under the snow

that was probably made
by an Arctic fox.

It's a time of plenty now,

but the bear family need to make
the best of it

because the good times are about
to come to an end.

As the weather warms,

the ice beneath the bears' feet
starts to break up and then melt.

And as the ice dwindles, so do the
bears' chances of a successful hunt.

Most of the ice is lost over these
shallow coastal waters,

where most of the seals live.

It's now summer and these bears
have a choice ... take their chances

on the shrinking ice floes,
or make for the safety of the land.

It's a case of sink or swim.

Bears have always gone
hungry in the summer,

but the length of time
when there's enough ice for them

to go hunting is getting shorter and
shorter, across much of the Arctic.

This is hitting cubs
particularly hard,

because they can't survive for as
long without feeding as their mother.

Cubs that were born
underweight are at the greatest risk.

This mother and her cubs may well
not get another meal

until the sea freezes again
in winter.

There's not much to eat on land and
the fact is that the longer the cubs

have to wait until the ice returns,
the more likely they are to die.

Longer summers with no ice
are probably the main reason why

many polar bear populations
are dropping.

To help monitor bears into the
future, this female is being fitted

with a radio collar to track
her movements.

It's an extraordinary sensation to be

so close to such a powerful animal.

With luck, carrying that collar,

she will have more years to go yet...

and be telling us a great deal

about herself and the rest

of the race of polar bears, as they

face this very uncertain future.

The future of the ice cover on
the sea isn't just

an issue for the animals.

It's a big concern for the people

who live in the Arctic

and travel across the ice every day.

David Iqaqrialu is an Inuit
from the village of Clyde River

in the Canadian Far North.

There are very few roads up here,
so David and his community,

like most Inuit people, have always
travelled across the frozen sea.

Dog sleds are the safest way to
get around because the dogs feel

thin ice underfoot and won't lead
travellers into trouble.

Old-timers, like David,
know the ice is as well as we know

the streets in our local
neighbourhood.

Every spring,

cracks have always formed in
the same places at the same time.

It's going to be big very soon.
After two weeks maybe...

it will be more open.

But now, cracks are appearing
where they never did before.

So, David and his friend,
Laimikie, have taken on a new job.

They are using special GPS units
to record the position

of new cracks or weak ice.

These findings will be used

by locals for their own safety,

but they're also being studied
by ice scientists,

who want to predict how the ice
will change in years to come.

The Inuit are keen to know what
the future holds too

because they've seen
with their own eyes the changes

that the scientists have seen
from space.

This satellite photo from 1980
shows the Arctic Ocean

at the end of the summer,
when ice cover is at its minimum.

Since then, there's been a 30%
drop in the area covered by ice.

But these images can't tell us about
changes to the most important factor,

the thickness of the ice.

Measuring thickness
across the whole ocean

was beyond scientists for many years,

until help came
from an unexpected source.

The Arctic Ocean is of huge military
importance, as it's the shortest

route between North America
and Russia.

Since the late 1950s, British,
US and Russian submarines

have been patrolling
the Arctic Ocean.

But as well as looking out for
enemy activity,

they've also been measuring
the thickness of the ice,

critical when looking for
a place to surface.

When scientists got permission to
look at the submarine crew's records,

they discovered that the ice
has been thinning fast.

In fact, it's nearly
halved in thickness since 1980.

Across most of the Arctic Ocean,

there are now just
a couple of metres of ice.

It's so thin that it could melt away
almost entirely in the summertime,

and that includes
the ice at the North Pole.

If current trends continue,
then there will be

open ocean here by summer's end,

some time within
the next few decades.

So, the days of the Arctic Ocean
being covered

by a continuous sheet of ice
seem to have passed.

Whether or not that's a good or
bad thing, of course,

depends on your point of view.

Nobody has had a better view of the
changes to the Arctic Ocean

than the people of Barrow,
the most northerly town in Alaska.

The people here have always
survived by hunting on the frozen sea

and they celebrate this
at a festival every year.

The blanket toss was once the best
way to spot distant animals to hunt,

as lifelong resident
Lewis Brewer explains.

When we throw ourselves up into the
blanket, you know,

you get that much more of an ''
of seeing further and further out,

so sometimes, you'll jump 15-20 feet
in the air,

and hopefully, you're being caught
right back into the blanket.

I'm OK!

But the old way of life
is under threat.

When Lewis was young, the sea stayed
frozen to the horizon until July,

and some ice remained
off-shore all summer.

But now, it's breaking up in June

and melting away completely
for two or three months.

I used to go out on the ice all
the time at this time of the year,

but we can't do that any more,
cos there's no more ice.

Lewis can also see that the
loss of sea ice is affecting

the animals he hunts for a living.

Since 2007, something very strange
has been happening

on this stretch of coastline,
close to Barrow.

Mother walruses, confused by the lack
of ice, are crowding onto the land

with their pups.

This very tight crowding isn't normal

and it's caused many youngsters
to be crushed to death.

Many Arctic animals are threatened
by the changing conditions

and that's also bad news
for the traditional hunters.

But the ice loss could be good news
for some people.

There are trillions of dollars' worth
of oil

and gas under the Arctic Ocean.

But the only way to get to them,

until now, has been by building
expensive artificial islands,

like this.

But if the sea ice goes,

it will be much easier to
drill for the huge riches below.

So, the countries that surround
the Arctic are scrambling

to stake their claims.

This daring attempt by the Russians
to claim the disputed seabed

at the North Pole in 2007 caused fury
among the competing countries

and it's unlikely to be
the last such dispute.

The Arctic has never been
so important

and not just because of
its resources.

The North-West passage,

a legendary sea route around the
north of Canada and Alaska, cleared

of ice in the summer of 2007 for the
first time since records began.

This promises a much faster

and cheaper shipping route between
the Atlantic and Pacific Oceans.

And some wildlife could benefit
from an ice-free Arctic too.

Bowhead whales are one of just
a few whales that can live

year-round in the Arctic
because they have no dorsal fin.

This means they can come up
for air in small spaces

and travel easily under the ice.

Their unique body shape used to
mean that the Arctic whales had

the seas to themselves
for most of the year.

But now, some cousins from down south
are moving in.

Killer whales are now a much more
common sight in the Arctic.

Their tall fins make it difficult
for them to travel under ice,

but the longer summers mean they can
travel much further north

and make the most of
the rich Arctic seas.

For animals and people,

it will be those that can adapt who
will thrive in a changing Arctic.

But the loss of sea ice isn't just
an issue for the Arctic,

because the state of the ice affects
the climate of the whole planet.

Because it's white, the ice reflects
up to 90% of the Sun's energy.

This is called the albedo effect
and it's why

we often see heat haze in the Arctic,
even when the air feels cold.

The frozen Arctic Ocean
acts as a huge reflector,

bouncing back the Sun's heat
into space.

Throughout history, that has helped
to cool the planet,

but when the ice melts,
it's a different story.

Because sea water is dark,
it absorbs most of the Sun's heat.

In the Arctic, this can trigger
a chain reaction, as the warming

water melts more ice, exposing more
water to the Sun's heat.

This cycle of warming, as huge areas
start to absorb rather than

reflect heat, is the main reason why
the Arctic, a region the size

of North America, is warming twice
as fast as the rest of the Earth.

So, melting sea ice is a big issue.

But there's another kind of ice
that could have an even more

dramatic impact on our world.

The ice that is found on land.

This is fresh water ice,

formed from thousands of years
of accumulated snowfall.

This is the front of a glacier,
quite a small one, believe it or not.

Glaciers are like rivers of frozen

fresh water flowing
across the surface of the land.

This one, like most polar glaciers,

is flowing down from a vast
inland ice sheet.

And it's what happens to those
ice sheets

that could radically alter
the face of the planet.

The Greenland ice sheet is by far
the largest in the Arctic.

It's two miles thick in places

and six times
the size of the United Kingdom.

Every summer, some of the surface
of the ice sheet melts,

forming sapphire blue lakes
of melt water.

More and more of these lakes
have been forming

as Greenland has warmed
over the last 20 years.

This lake has grown over several
weeks and now it's overflowing,

carving a deep channel
through the ice.

A network of channels criss-crosses
the ice sheet,

but many of them
come to an abrupt end.

Huge holes, like this,
can open up quite suddenly,

draining the melt water away.

Alun Hubbard is a glaciologist,
studying the enormous power

of these waterfalls,
which are known as moulins.

We've got this amazing moulin
going off here today.

The water's overflowing from the
lake, which is beginning to drain.

Tonnes of water cascading down
this pipe that is, effectively,

plummeting to the depths
of the ice sheet through

over a kilometre of vertical ice.

Alun is here to study where
the melt water goes

and what effect it has on
the remaining ice.

To do that, he needs to find a
moulin that has recently run dry.

Just a week ago,
there was a three-mile long,

ten-metre deep lake here.

The weight of all that water
cracked the ice beneath

and the late drained in just
a few hours with incredible force.

Thousand-tonne ice boulders
were tossed about like dice.

Alun's team have found the hole
down which the lake disappeared

and they want to have a closer look.

It's not a job for anyone
with a fear of heights.

As you can see, it's dry up here,
but if you listen,

you can hear the thunder of,

there's a lot of water entering it
at some depth.

Alun wants to place a sensor
deep into the moulin to discover

how much water is flowing
through the ice.

As they drop,
they travel back in time.

30 metres down and they reach
ice formed from snow that fell

10,000 years ago,
in the last Ice Age.

When this lake drained and the plug
got pulled and the whole lot

flushed down through here,
this ice sheet, it rose by a metre

as that water accessed the bed
and forced, jacked up the ice sheet.

So, we know that the water

in this whole plumbing cavity
system, down here,

we know that shoots straight
through that ice

and actually hits
the bed of the ice sheet.

We've hit the water,
I can see the water now.

Great. Nice work.

This daring experiment is
measuring how the water flowing under

the ice sheet affects the speed
with which the glaciers

flow from it, down to the sea.

The theory is that the water is
acting as a lubricant.

So, the more water there is,
the faster the glacier flows.

To the naked eye, glaciers don't
appear to move at all.

But move, they do.

These unique time-lapse images were
captured over the last four years.

Through long observations,
we now know that Greenland's ice

is flowing down to the sea twice
as quickly as it was 20 years ago.

The speed of the glaciers
affects our sea levels

because when they reach the water,
they break apart into icebergs.

Occasionally, a real mega-berg
is born.

This is the Store Glacier
in May 2010.

75 million tonnes of ice,
that had been sitting on land

for thousands of years,
has broken away.

Events like this have become
increasingly common,

as Greenland's glaciers flow faster
into the sea.

Every single one of these icebergs
raises the sea level a small amount.

Scientists monitoring the ice sheet
predict that Greenland might add

as much as a half metre to world sea
levels by the end of the century,

enough to swamp many of
the world's low-lying islands.

99% of the Arctic's fresh water ice
is in Greenland.

It's a staggeringly big ice sheet,
but it's just a drop in the ocean

compared to that at the southern end
of our planet.

In Antarctica,
there is ten times more ice,

by far the largest
concentration of ice on Earth.

Our exploration
of the Antarctic only began

a little over 100 years ago.

The study of ice retreat here was
unwittingly begun

on an expedition led by the great
early explorer Ernest Shackleton.

In 1916, after their expedition boat
was crushed and sunk by ice,

Shackleton and two companions set
off to summon help in a tiny boat.

They sailed over 800 miles
across the Southern Ocean

to the island of South Georgia,
on the edge of the Antarctic.

Near starving and dressed in rags,
the three men

walked across the ice sheet at the
centre of the island, knowing there

was a whaling base on the opposite
coast where they could summon help.

This team of Royal Marines is
re-tracing the steps

of that journey in tribute
to Shackleton and his men.

But for all their efforts, they can't
exactly copy the great walk

because the ice is not as it was.

A number of South Georgia's glaciers

were photographed

by Shackleton's cameraman.

Frozen Planet saw a dramatic change

when they returned 94 years later.

Most of South Georgia's glaciers
have shrunk since Shackleton's time

and most of that has happened

since I first went to
the Antarctic 30 years ago.

I've been to South Georgia
several times

and seen how greatly the glaciers
there have changed.

This photograph of a glacier

reaching right down to the sea

was taken just six years

before I first visited in 1981.

Now, that glacier has retreated
by 400 metres away from the beach.

Temperatures in South Georgia have
risen sharply, but the Southern

Hemisphere's most dramatic warming
has happened a little further south.

In recent years, stronger winds
blowing over the Southern Ocean

have brought warmer air to the 800
mile-long finger of land that forms

the northern extremity
of the Antarctic continent.

Here, on the Antarctic Peninsula, the
changing wind patterns have driven

temperatures up by nearly
three degrees Centigrade

over the last 50 years.

Ten times the average rate
of the rest of the planet.

The rapid warming is having
a big effect on the birdlife.

The Adelie penguin is the most
southerly nesting of all penguins.

And, like the polar bear,
up in the north,

their lives are dependent
on the sea ice.

Adelies spend their whole lives
near ice.

These birds have spent
the winter feeding at the ice edge,

but now it's spring

and they've started a long trek
over the frozen sea towards land.

They're heading for areas
of exposed rock, where they gather

to breed, in colonies that can be
over 100,000 strong.

But it seems that Adelies don't
find the conditions

on the Peninsula
to their liking any more.

17 years ago, when I was last
in the Antarctic, there were

large colonies of Adelie penguins
all along the Antarctic Peninsula.

Now, warming temperatures
have meant less sea ice

and Adelie penguin numbers
are in decline.

Many colonies have been
emptying fast.

It may be that penguins are starving,

or it may be that they're heading
south to colder climes

where there's still plenty of ice
on the sea.

But, as in the Arctic,
while ice-loving animals are feeling

the heat, animals that like it
a bit more cosy are moving in.

The bright orange beaks of Gentoo
penguins are a much more common sight

on the Peninsula these days.

I always used to know them
as residents

of the slightly warmer islands
north of the Antarctic.

But they've moved south in numbers.

There are thought to be ten times
more Gentoos on the Peninsula now

than just 30 years ago.

The peninsula has warmed
a great deal,

but the same is not true
further south.

The Antarctic continent is smothered
by the world's greatest ice sheet.

One and half times the size of
Australia

and up to three miles thick.

A staggering 75% of the Earth's
fresh water is locked up in this ice.

Global sea levels would rise by some
60 metres if all this was to melt.

But what chance is there of
that happening here in the coldest,

most hostile place on Earth?

The ice beneath me, up here
on top of the ice cap, is so thick

that I am short of breath,
simply because of the altitude.

This is midsummer

and the average temperature is
some 20 degrees below freezing.

And I can tell you it feels
much lower than that.

And even the worst predictions
don't suggest

that the air is going to warm enough
to melt the ice.

But now, scientists are asking
a different question.

Could the speed at which
the Antarctic ice flows off the land

be increased by a warmer ocean?

Where the ice sheet meets the sea,

scientists are going to
extreme lengths to find out.

Firing.

Andy Smith works
for the British Antarctic Survey.

What we have here is one kilogramme
of pentolite explosive.

We're going to use this
to generate a shockwave

and record the echoes that come back
from underneath the ice.

Firing.

Andy is particularly
interested in mapping

the underside of the ice
around the coast.

Because here,
it isn't resting on land.

It's floating on sea water,
so if sea temperatures rise

just a little,
it can be melted from below.

Around the coast of Antarctica,

the glaciers have flowed out across
the sea to form immense masses

of floating fresh water ice,
called ice shelves.

These freeze to the land around
them, sticking fast and acting

like bathplugs, holding back the
flow of the glaciers into the sea.

On the Antarctic Peninsula,
a one-degree sea temperature rise

has helped to break apart seven major
ice shelves in the last 30 years.

This is the Larsen B ice shelf,

three times the size of Greater
London, breaking apart in 2002.

Afterwards, the glaciers it had been
holding back

started flowing
up to six times faster.

In 2008, a much larger ice shelf
at the southern end

of the peninsula started to break up.

It's an enormous event
that's never been filmed before.

Andy Smith is flying
down the Peninsula to study

this phenomenon first hand.

We're flying to a place called
Wilkins Ice Shelf.

It's an ice shelf that,
over the last couple of years,

has shown a very sudden
and dramatic break-up.

The Wilkins Ice Shelf is
a two-hour long flight south

from his research base,
but Andy can start to see

the evidence of ice shelf break-up
a long way before he gets there.

As we're heading further south,

we can see more and more
icebergs in the ocean.

And most of the big ones
will be ones

that have broken off
the ice shelves in this area.

Once we cross the mountains,
we should be able to see

Wilkins Ice Shelf and then it's not
far then to the ice front, here,

where it's collapsing.

As Andy's team reaches
their destination,

the scale of what's been happening
soon becomes clear.

Here, for thousands of years,
an area the size of Yorkshire

has been covered by a sheet of ice
200 metres thick.

But now,
over half of that has broken apart.

Andy has been studying
Antarctic ice for 25 years,

but even he is blown
away by what he's seeing.

Now, that is pretty awesome.
That is remarkable.

The edge of the ice shelf has just,
kind of, disintegrated.

Some of the big pieces look like

they could be a mile or more
in size.

It's almost like a, sort of,
a slow motion explosion.

It all pushes outwards very quickly.

Every one of these huge icebergs
will slowly drift out to sea.

To study how fast that happens, Andy
needs to get closer to the action.

We're going to look around and see
if we can find a place where

we can land. And if we can, we'll be
able to put down an instrument

that will help us monitor the big
icebergs that are breaking off

as the ice shelf breaks up.

Landing on an iceberg is another
first for Andy's team.

This satellite transmitter will help
to track the continued break-up

of this colossal ice shelf.

The remainder of the Wilkins
looks set to break apart soon.

It's the latest ice shelf to
disintegrate in a wave that's been

travelling southwards,

playing a major role in the loss
of ice from the Peninsula.

Next in line, and already weakening
in places, are the ice shelves

that hold back Antarctica's gigantic
continental ice sheet.

And it would only take a small
corner of this to slide into the sea

to have major global consequences.

We've only started to see changes
in the Arctic and Antarctic recently.

So, it's hard to predict exactly what
impact these changes will have.

But we can see for ourselves
that these places are changing

and on a scale that is hard
to ignore.

The Poles, North and South,
may seem very remote,

but what is happening here is likely
to have a greater effect upon us

than any other aspect
of global warming.

If the Arctic sea ice
continues to disappear,

it will drive up the planet's
temperature more quickly.

And the melting ice sheets could
contribute to a sea level rise

of a metre, enough to threaten
the homes of millions of people

around the world's coasts
by the end of the century.

We've seen that the animals are
already adapting to these changes,

but can WE respond to what is
happening now to the frozen planet?

The increasing unpredictability
of the ice was a big issue

for the Frozen Planet team, who spent
three years working on top of it.

Whether on sea, land, lake or river,

the state of the ice was the first
concern for most filming crews.

Unexpected break-ups left many a
cameraman in need of a swift rescue.

Sometimes, help came by boat,
and sometimes by air.

I had a chance to see the changing
ice conditions for myself,

when I visited the North Pole.

I flew with the team to a temporary
camp that is set up every year in

the centre of the frozen Arctic Ocean
to support expeditions to the Pole.

I had never visited
the North Pole before,

so this was a great highlight for me.

But it was hard going
in temperatures of minus 40,

so as soon as filming finished,
we flew south.

Little did we know that
we had made it out just in time.

We got back from the Pole camp
last night and I've just bumped into

the Russian Commander,
who's just heard from the camp.

And the news is that a little crack,
which I'd seen in the ice

between our tent and the airstrip,
which was no more than an inch

or so wide, has, overnight,
widened to 20 metres.

Temporary break-ups,
caused by stormy weather

and strong winds, have happened
before, but they've been getting

more and more frequent over recent
years as the ice has got weaker.

It was only swift action
by the staff that prevented

a lot of valuable equipment
going in the drink.

The biggest concern was that the
ice airstrip might break apart,

but, luckily, it held
and everyone was able to evacuate

when the weather improved.

The Frozen Planet team's
clearest demonstration of the power

and unpredictability of breaking ice

came when they went to film the
melting of a frozen Canadian river.

Producer Mark Linfield

and researcher Matt Swarbrick have
travelled to the far North of Canada.

Matt, when was the last time
we saw a car?

I don't know, about three hours ago.

They've driven through the vast
Northwest Territory on a mission

to film the moment when
this frozen waterfall breaks apart.

The break-up, when the frozen
river above the waterfall thaws

and masses of water start to flow
again, can be a spectacular event.

But predicting exactly when
it's going to break

is the big challenge, if Mark and
Matt want to get the best shots.

And they're not the only ones
who want to know.

When the waterfall breaks,
it can flood the town of Hay River,

just downstream, with
millions of tonnes of water and ice.

Mark is taking advice
from the scientist Fay Hicks,

who has the job of predicting
when the ice will break.

What happens is, you get ice jams
form upstream and they start to dam

up the water and it builds

and builds and builds,
and that can let go,

and that's a much bigger wave of
water, you know,

than just the normal flow.

So, it just depends upon how
dramatically it unfolds.

Fay takes her research helicopter
to monitor the situation

upstream of the waterfall.

Just ten miles up river,
the ice is starting to break.

The locals are concerned because
huge amounts of water can build up

if these ice chunks dam the river,

and that can lead to devastating
flooding in the town,

when the dams burst.

Sound of it's moving through
there now.

Yes, got a shot.

Using cameras and sonar to assess
the state of the river,

Fay makes her best guess at
when this break-up will hit

the waterfall just above the town.

Now, guys, I think we have about
48 hours to go.

Fay's prediction of the 24th April
is exciting news for the team.

Upstream from here, it's already
starting to melt and Fay thinks that

we may only have another one or two
days before this whole thing goes.

Which is almost impossible
to imagine looking at it now,

but that's what she says.

With the break-up seemingly imminent,

the team set up
their cameras in anticipation.

Over the next 48 hours, the weather
warms to well above freezing,

but there's no sign of the break-up.

The team waits and waits and waits.

Mark is concerned that the crew have
to return home soon, so

he heads into town to get the advice

of long-term resident Red McBrian.

We just have to live with it and
take whatever evasive action we can.

Red has had 50 years
of witnessing the power of the river.

Well, we're hoping that she may
break up in two or three days.

No, no, no, that's too soon.
No, no.

Boys, you're looking at seven
or eight days

before she breaks of any
significance.

And if she breaks, she can jam
and hold up. She can be...

She'd be down here probably
around the 5th or 6th May.

The townspeople are on tenterhooks,
waiting for the big day,

but another week goes by
before anything starts to happen.

Finally, it seems that things
might be happening.

We've just heard some cracks
from upstream,

so, if we're lucky,
we might get some action.

Seven o'clock, which gives us
two hours of light. Two hours.

If it happens at night,
we're going to miss the whole thing.

Sure enough,
the town is put on red alert

that the river is about to break
in the middle of the night.

They've just called a full
evacuation of the Eye Inn,

where we're staying, and if we don't
move now, we're all going to be

underwater and possibly get trapped
here for a few days.

The team have to move out
and get up to the waterfall,

hoping that it doesn't break
before it's light enough to film.

Luckily, the Sun is up
before the main event begins.

That is a serious amount of ice
coming around the corner.

After weeks of waiting,
the sleeping giant of a river,

we thought nothing was go to happen
and suddenly, look at this!

This is what we're here for.
Unbelievable.

Absolutely unbelievable. Holy ...!

The team is used to handling
multiple cameras,

but they don't usually have to dodge
ten-tonne ice floes at the same time.

As you can see, it's racing
over at unbelievable speed.

The power, I just, if you were here
to feel this, it's a deep rumbling

sound of the river, I can feel it up
through my feet.

The power, I just can't imagine.
That could crush a house in no time.

The team takes to the air to witness
the destruction that's unleashed.

Huge ice blocks are pushed
downstream on the wave of water

released by the breaking waterfall.

This could devastate the town.

But, this year,
the townspeople's luck is in.

The town has escaped flooding.

Crucially, the ice blocks did not
dam the river, it's running free.

And the date of the break-up,

the 6th May.
Red's got it right again.

I don't use any of these here gauges
and mechanical assistance,

I just go by what I see on
the river as I walk it down.

And I say I walk it down, back and
forth every day on the river to see

what's happening, and from that,
I gauge when it's going to hit here

and what the situation is going
to be like when it does get here.

You know,
when it went this morning,

I said to my students,
"Guess what the date is?"

Red told us it was the 6th May
and we were, you know, I'm not

surprised, because we've been here a
couple of times and that's happened.

Ten days, two weeks out and he just
looks around and goes "5th May."

How does he know that?

It's incredible.

It's because he just has lived
on this river

and lived this break-up
for 50 years.

Ice scientists are improving
the accuracy of their predictions

all the time, but in the meantime,

the people of Hay River have a
remarkable guardian.

Red, you were completely right this
year. Are you right every year?

No, I'm...

I miss the odd one.
Yes, 1985, I missed it.