Documentary series about the weather. A look at rain, including the true shape of a raindrop, how and why rain falls, and stories of adaptation to this elemental force of nature.
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and it pours.
In English it rains cats and dogs.
In Welsh it rains old women and sticks.
Rain nurtures the grass for our sports grounds,
it gives us green countryside
and the sliding tackle.
As you can see, we're in the middle of summer
and we are here in the rain.
You really witness this a lot of the time -
water, water, water.
So how has our frustration and fascination with rain
driven our attempts to understand it?
How did we learn to predict it?
And protect ourselves from it?
Rain has been a spur to scientific breakthroughs
and revolutionary inventions.
We once hoped these would allow us to master it.
Now science tells us our rain is likely to become wilder
and less predictable.
How will that affect this very British obsession?
We're going to have to reckon with the fact
that rain is back as a threat to us
in a way that the Victorians and the scientists of the 20th century
thought they might eliminate.
FEET STAMP IN PUDDLES
BAND PLAYS A JAZZ TUNE
If there's one thing the British know about it's rain.
But there's a paradox.
It's an essential ingredient for what we love about Britain.
Yet we love to complain about it. That's what makes us British.
We want it to be out of the picture
and rain comes along and spoils that party. We're not happy.
We're anxious, we're fretful, we're cross.
Trying to plan our lives around rain is an exasperating business.
It has a tendency to disrupt our national life.
We sort of quite irrationally think it should always happen at night,
or it should happen some other time,
and when it happens during Wimbledon it seems unreasonable - unfair.
SPECTATORS GROAN AND MUTTER
# Into each life
# Some rain must fall
# But too much is falling in mine... #
All our efforts to calculate around it are in vain and we know that.
It's regarded as devious and tricksy.
# ..Some day the sun will shine... #
I think about the rain probably seven or eight times a day.
For instance, this year's final. I only watched a couple of minutes.
Most of the time I was looking at the clouds.
When it rains, it's the referee's responsibility to stop play.
Most of the time it's a very easy decision
because if it's hard, that's it.
We've stopped matches on match point before now.
The criteria being when it gets dangerous for the players.
If it comes on very heavy, then you've got to stop it immediately.
Eddie Seaward has been head groundsman here for 15 years.
What he doesn't know about rain in this corner of South London isn't worth knowing.
And he's noticed that the pattern of rainfall has changed.
At one time we used to come in and if we got 2mm overnight,
that was considered a lot of rain.
Now we get 10-12mm without thinking too much of it overnight.
I think that's the biggest thing. When it does rain it rains more and there's greater volume.
Trying to understand rain - its changing patterns, its origins,
has always fascinated British scientists.
Clive Saunders has studied rain for over 40 years.
In his laboratory at the University of Manchester,
he injects water into an air stream to simulate a rain drop as it falls to earth.
It's taking the natural shape
that it would have if it was a rain drop falling inside a cloud.
And you can see that it has a flat base,
is oval in shape,
and it certainly doesn't have the teardrop shape
that is sometimes drawn in cartoons.
I think there's this fallacy that a rain drop is the same shape as a tear drop
and so it's an interesting metaphor.
So you can have a thing like - "My tears fell like rain"
or "rain fell like tears".
But I think it's much more of a bodily function than that
because rain makes cold and clammy and wet and that feels miserable.
The true shape of a rain drop
was discovered by scientist Philip Lenard in 1898.
He saw that as rain drops fall they become flat,
resulting from the tug-of-war between the surface tension of water
and the air pushing up from below.
Lenard's experiment also shows how rain drops combine.
So this would be quite a large rain drop,
falling at several metres per second in the atmosphere.
But it can collect other drops as it falls.
Then two rain drops collide together to make a bigger one.
So that will fall faster,
which is how they grow - smaller ones collected by bigger ones.
These water droplets are between one to two mm in diameter -
the size of an average rain drop.
But away from the lab, rain drops can be much larger.
The largest drops of rain ever recorded
were nearly one cm in diameter.
So we know what it looks like but where does rain come from?
The Greeks were among the first
to give us a scientific explanation of rain.
Their investigations into the natural world
convinced them rain was part of a cycle.
Water evaporates into the atmosphere and falls back to earth as rain.
The Greeks were remarkable
because they were the first to think of the natural world
as having an integrity of its own -
not necessarily just gods and goddesses doing their tricks.
That was present in the Greek world as well
but on the other hand you start to find people like Aristotle
with the idea that the natural world has its own physical integrity.
The realisation that in the heat of the summer water goes up
and it comes down and you have the basis of the hydrological cycle.
Aristotle doubted that rain alone
could account for all the water on earth.
He believed that our rivers and lakes must be fed by a series of vast underground seas.
It wasn't until the 17th Century that a new theory challenged this idea.
European scientists argued that evaporation and rain was sufficient
to supply all our rivers and lakes.
It took a young British genius to prove it.
In 1687, Edmond Halley, of comet fame,
devised a simple experiment
that transformed our understanding of rainfall.
Halley is an IMMENSELY significant thinker
in the history of the study of rain.
Now, what he does is this.
He says, "I took a brass pan of eight inches in diameter
"and four inches deep
"and filled it perfectly brimful on a normally warm summer's day
"and weighed it.
"Two hours later I re-weighed it and I noticed how much had gone."
Using this rate of evaporation as a measurement,
he calculated how much evaporates from one degree of the ocean -
an approximate area of 69 square miles -
during the course of just one day.
And then he gets a STAGGERING figure.
In every single day -
in the temperate latitudes of the globe, let alone the tropics -
every single degree is yielding
33 million tons of water into the air.
Halley's astonishing calculation showed millions of tons of water
move in a constant daily cycle of evaporation and rain
in what we now call the hydrological cycle.
The total amount of the Earth's water does not change
but the distribution of rain varies enormously across the planet.
It's a distribution that can play havoc with our most treasured cultural traditions.
Nothing captures the essence of the British summer more than cricket.
But cricket suffers more from the impact of rain than any other sport.
It's a typically British game.
It's a fantastic game -
influenced by the weather sometimes in a negative way by stopping play.
TV COMMENTATOR: Ground staff have got to be quick here.
It's absolutely hammering down.
Just look at this! Who'd be a groundsman?
A dreadful day for everybody concerned. It's bucketing down.
Cricket is played during this wonderful thing called the English summer.
Unfortunately, we've had a record-breaking spell of rain
here in South Wales in the last week.
The average rainfall in September in Cardiff
is somewhere in the region of 10cm.
We've, in the last week, already had 12. Very, very unusual.
The ground has literally become saturated just by the sheer volume.
It's always a very colourful scene when rain drops
but it's not the scene everybody wants.
We are optimistic.
The forecast here for the rest of the day and for tomorrow is for reasonable weather,
so we should have some play later.
# ..It's a lovely day tomorrow
# Tomorrow is a lovely... #
But this optimism was confounded.
For the first time ever at this ground,
not a single stroke was played over the course of a four-day match.
# ..Just forget your troubles
# And learn to say
# Tomorrow is a lovely day... #
In Britain, rain can do far more than disrupt our sport.
It can threaten lives and destroy homes.
In the summer of 2004,
an entire village - Boscastle in Cornwall - was devastated by rain.
Any flood which happens in the West Country during the summer
is a collusion of meteorology and geography.
You need the heavy rainfall first of all
but because the river catchments are, generally speaking, very small
they respond very quickly to rain which falls on them.
If the cloudburst happens exactly over that catchment,
then all the water will find its down the river
and out to sea in a matter of hours.
Monday 16th August 2004.
Visitors in Boscastle are enjoying the morning sun.
At midday, just a few miles away in the hills above the village,
heavy rain begins to fall.
At the end of the main street is a 14th-century building.
Now a shop, it's one of the most popular attractions in the village.
The owner is Trixie Webster.
The day started off quite warm and sunny
but round about midday we had this sort of ominous black cloud
and it started raining.
The first showers took visitors by surprise.
But much heavier rain was falling on the slopes above the village.
This water was being rapidly funnelled down the narrow valley...
..and heading straight towards Boscastle.
Just before three o'clock in the afternoon,
it came up to the top of the old bridge
and I realised then we were going to have a flood.
A huge torrent surges through the centre of Boscastle.
Many don't realise their lives are at risk from the fast-flowing water.
But soon people call the emergency services for help.
RADIO: 'We do need assistance urgently. We need police certainly.
'The roads are all blocked now and it's absolute chaos here.'
'..reportedly cut off by the cafe.
'Roger. We'll go and investigate.'
The surging river is fuelled by one of the most extreme downpours ever experienced in Britain.
Eight inches of rain falls on the hills in one day.
Well, we did everything we could.
We put up storm boards,
sand bags on all the buildings that we thought might be flooded.
In Boscastle, 3.5 inches of rain fell in one hour
and events escalated rapidly.
The sewage system collapses.
Hundreds of tons of thick, dark sewage mix with the flood water.
And the sheer power of the water -
the volume of it. It was muddy, it was smelling.
The river burst its banks
and flood waters threaten Trixie Webster's shop.
The first thing was the volume of water I saw -
it just dismissed the sandbags and everything else
and just broke open the door.
And we have three windows at the back and it burst through those windows.
The flood destroyed the contents of Trixie's shop
and swamped many other buildings in the village.
The emergency services are now inundated with calls.
'This is serious flooding, we are talking three foot deep down the main road.'
'You're through to the police. What's your emergency?'
'We've got a road flooded and people in danger.
-'How many people are trapped?
'There's a flood here. A really bad flood and people are getting injured.
-'We need some emergency services down here.
-Whereabouts are you?
'In the car park.' SCREAMING IN BACKGROUND
The noise was just colossal.
You literally couldn't hear yourself shout.
It turned into a ballistic scene of just utter carnage.
Water cascades through the centre of Boscastle
at a rate of 140 tonnes per second.
A wall of water sweeps cars through the village
and smashes them into buildings.
METAL CRUNCHES AGAINST STONE
Trixie's shop is battered.
Every car that came down smashed into it. It didn't stand a chance.
Trixie Webster's 14th-century shop,
at the end of the main street, simply disappears.
HELICOPTER WHIRRS OVERHEAD
It was only the next day,
when the waters had subsided
and we saw the devastation. That was the shock, really.
The 400-year-old building was gone.
It was like a bereavement, actually.
If you look through the records,
you can find examples of previous floods in Boscastle -
probably once every 15 or 20 years -
not to the same extent as the 2004 event but the same pattern.
The weather can always throw you something worse than before.
Records are there to be broken.
The unpredictable nature of rain reveals the British character.
When it rains too much, we complain bitterly.
And when the sun comes out, we celebrate.
# Wow! We're having a heat wave
# A tropical heat wave... #
MUSIC: "You Sexy Thing" by Hot Chocolate
A tropical heat wave in 1976
became the longest dry spell in over two centuries.
The British abandoned their normal reserve, soaked up the sun
and swarmed to the seaside.
# ..I believe in miracles
# Where you from?
# You sexy thing
# Sexy thing, you... #
The holiday spirit blossomed
and a new, uninhibited culture took hold of the nation.
But the 1976 heat wave soon became a drought
and we badly missed the rain.
TV: Save or suffer, it's up to you.
The country was thrown into turmoil as water was restricted
and reservoirs ran dry.
A similar drought 100 years earlier, in the 1850s,
lasted for several years.
The Victorians worried that there wouldn't be enough water
to supply their industrial revolution
and the rapid growth of towns and cities.
But this drought led to a great step forward in meteorology
and our understanding of British rainfall.
In the late 1850s, there was a crisis of drought
and, as it happened, in the late 1850s,
there was a young man with a fascination for the weather -
a young Londoner, George James Symons.
He saw that all the talk about this crisis of drought lacked something,
there was something missing,
and it was a scientific basis for discussion.
Everybody knew there wasn't enough rain
but nobody knew how much less rain there had been than before.
Nobody knew how the patterns across the country worked.
Nobody knew the longer-term picture.
How often does a drought like this happen?
And he set himself the task of answering those questions
and it's a great threshold in the history of meteorology.
Here was somebody who said,
"Look, let's not rely on the sayings of shepherds
"to inform our understanding of rain, let's measure it."
The drought of the 1850s ended with a welcome return of the rain.
George Symons began to take rainfall measurements.
These are some of his early handwritten records.
He understood that only with accurate data,
collected from all over the country and over many years,
would it possible to discover a pattern to British rainfall.
It was a giant undertaking
that consumed Symons for the rest of his life.
He took out advertisements in local newspapers saying,
"Would anybody care to measure rain?"
And there was a craze.
The response to Symons's advertisement was staggering.
From prisoners to admirals of the fleet,
people signed up in their scores to become rain collectors.
Symons asked them to send in their rainfall measurements
and he standardised the way rain should be collected,
so everyone could use the same type of rain gauge.
This museum piece is a traditional rain gauge.
It's the same sort of instrument
that Symons would have used 150 years ago.
It works very, very simply.
The rain falls into the funnel, which is exactly five inches across.
The water finds its way down through the tube
and into a collecting bottle
and there we see the rain which fell last night, which we can measure.
And it tells us that the rainfall last night was exactly 6.2mm.
Rainfall collectors throughout the country
sent their readings back to George Symons.
He was a bit of an anorak, really. He liked playing with numbers.
Symons painstakingly transcribed the numbers
and produced annual statistics.
And such was the demand for regular updates from the British public
that from 1866 he issued monthly rainfall reports
in Symons's Monthly Meteorological Magazine.
I think when you hear that phrase,
"since records began", when people talk about the rain,
everybody should think then about George James Symons
because he was when records began. He started it.
Until he came along there was a sense that this was just so big,
it was un-measurable,
nobody could imagine how you would nail down
enough information about rainfall for it to be useful.
Here was somebody who was prepared to think big and be ambitious
and, you know, he's a marvel.
Symons died in 1900 after 40 years of studying British rainfall.
His data sets give us the oldest rainfall records in the world.
And he never received a penny of public money.
He was buried in Kensal Green cemetery
amongst the great and good of London society.
The Times reported on the large crowd of distinguished scientists
who gathered here to send him off.
Well, this is the grave of George James Symons -
the great pioneer of the study of British rainfall.
There isn't a headstone. There's a stone there
but there seems to be nothing on it. There's no record here.
Nothing to help us remember this man
who told us more than anyone about the rainfall in Britain.
If we really were obsessed with the weather, as the legend has it,
surely he'd be a hero
and surely he wouldn't be there in an unmarked grave like some pauper,
a forgotten pauper.
I suppose he would be consoled with the idea
that he's left us his fantastic data sets
and he has left us the ability to say,
"The wettest July since records began".
There's the man who made those words possible.
I'd just like to think it was possible to come
and remember him in some way.
That a passer-by might have a chance to say, "Oh, see what he did!"
Over time, Symons's collection of measurements
revealed the pattern of British rainfall.
It showed a Britain divided in two.
Most of our rain falls in the north and west of the country,
leaving the south and east relatively dry.
And he discovered one of the most stunning areas of Britain
is also the wettest.
The Lake District.
This lush, green landscape draws thousands of tourists each year
and it largely owes its beauty to the rain.
Green grass, rivers and lakes.
All a result of regular rainfall.
No surprise then that Seathwaite, in the valley of Borrowdale,
is arguably the wettest inhabited spot in Britain.
Showered by rain all year round,
Seathwaite has an average yearly rain fall of 120 inches.
# The sun is out
# The sky is blue
# There's not a cloud to spoil the view... #
Mark Weir has lived in the area all his life.
# ..Raining in my heart... #
I've witnessed this weather for 42 years.
When you've been born here
and you understand the weather patterns, you get on with it.
I'm incredibly happy when I leave Borrowdale
because there's always sunshine everywhere else.
You really witness this a lot of the time,
which is water, water, water.
I would like a little bit of sun, please!
# ..The weather man says clear today... #
At the top of a hill pass in the Borrowdale valley
is Mark Weir's slate mine -
one of the few underground slate mines still working in Britain.
A conscious decision when I bought this 12 years ago
was do I want to work outside and be rained off most of the time,
or do I want to go underground?
I think the origin of mining began here
because underground everybody can continue to work
regardless of the weather on the surface.
The Lake District has something to offer even in the wet. You know?
It is quite beautiful being at one, on the mountains,
in the driving rain.
It seems to be getting more tropical now,
more heavier rain than we used to have.
And we seem to have more tourists visiting here when it's wet.
They're treating the mine as a wet-weather experience,
which is good for my business because it continues to grow.
So if global warming is a situation where we have more rain,
that's good for my business.
So you really need to get your shares in now!
# ..Oh, misery
# What's gonna become of me...? #
So why does the Lake District get more rain
than other parts of Britain?
When winds full of moisture from the Atlantic hit the Lake District,
hills force the air upwards.
When air rises it cools
and the moisture condenses into water droplets to form clouds.
If these water droplets are large enough, they will fall as rain.
It's the western side of the British Isles that gets this
and that's because it's where the air that has come from the Atlantic -
it's blown over all that ocean, it's picked up lots of water -
and this is the first land it's reached for thousands of miles.
So it says, "Thank you, I can release my water over the Lake District."
Clouds are much more complicated than people think.
They are a manifestation, if you like,
of the moisture in the atmosphere.
Most clouds actually don't produce rain.
They're fair weather clouds and they just stick around
and block the sun out and don't do anything else.
But certain sorts of clouds, especially the thicker ones,
and especially if there is upward motion in them -
in other words the air is rising in the cloud system -
they will produce rain.
It is our understanding of which clouds
are likely to produce rain and which are not
that marks our ability to forecast the weather accurately.
It was in 1803 that clouds were first classified
into the different types that we know today,
by Englishman Luke Howard.
Luke Howard was a London Quaker and businessman
who had two business premises in different parts of London
and walked between the two.
As he walked, he looked up into the sky and he saw clouds
and he started to think about clouds.
And he began to see, well, I could sort these.
That's a fluffy one that seems to go up very high.
That's a sort of flat grey one...
and that one's a sort of streaky thin looking one
that I can almost see through.
So, if I give these names and then work out what's between those,
what other kinds are there?
And he started to classify the clouds
and he gave them Latin names.
Puffy white cumulus that look like cotton wool.
Stratus that form in layers and cover the sky in a blanket of cloud.
Cirrus and altocumulus that form high in the sky.
And the ominous cumulonimbus - dark grey clouds
that can stretch all the way to the ground, bringing rain.
It's such a simple idea and yet it is,
as he put it, the key of analysis.
Up to that point, the knowledge that was accumulated about clouds,
by individuals, was lost because it was not possible to exchange it.
Here he had given the clouds types
which could be standardised throughout the world and were.
The understanding of clouds and their behaviour,
their likelihood of bringing rain,
all that is suddenly much more clear.
The 19th century advanced our understanding of the water cycle
but a great challenge remained.
What happened to water vapour as it rose into the atmosphere?
It was a challenge embraced by James Glaisher, one of the leading scientists of the day.
The atmosphere was uncharted territory
and the only way for Glaisher to get there was in a balloon.
Balloons were well established by the 1860s, when he's doing his work.
And the first place you go for a balloon ascent is the entertainments industry
because balloons in the Victorian period were not used scientifically,
they were used for spectacular thrills and spills.
Glaisher realised that balloons could be used
for scientific experiments
and he approached a celebrity aeronaut of the day, Henry Coxwell.
In 1862, they planned a series of balloon flights
to study the moisture content of the air.
The classic was the ascent he makes on the 5th September
from Wolverhampton Gas Works.
Glaisher gathers together scientific instruments,
fills the balloon basket and lifts off.
And what he was after was this.
At what altitudes will the air carry
what particular quantities of moisture?
This he realises is crucial for rain and for evaporation.
He takes up these 17 instruments
and is monitoring them literally second by second.
They rose into the cloud, passed through the cloud.
And then Glaisher tells us they broke through onto a plateau of cloud.
And you could see this brilliant white cloud below you.
Glaisher took regular readings of temperature and humidity
but there was danger ahead.
At 29,000 feet, their lives were in peril.
Now, that is nearly five miles.
Up at that altitude, he seems to have lost his senses.
This was the highest manned balloon flight ever attempted.
And at this height, there was not enough oxygen to breathe.
Glaisher's hands went numb and he soon passed out.
The adventure seemed sure to end in death for James Glaisher
and his pilot, Henry Coxwell.
Coxwell had got so cold and so paralysed,
he claims his hands had not only completely failed to function,
they'd gone black from lack of oxygen.
They would almost certainly have been doomed to die.
The balloon would have ascended and ascended
until the gas pressure became so great it just burst
and down you would have come!
Coxwell claims he held the ripcord of the balloon with his teeth,
pulled it three times,
until he felt there was sufficient fall coming down.
Then he let more gas out
and slowly the great balloon starts to come down.
It was a narrow escape.
Undeterred by his brush with death,
Glaisher resumed his experiments and observations.
These are determined scientists
and once he starts getting his senses back,
Glaisher then starts to re-monitor the instruments
as soon as he's regained consciousness.
That whole flight took about two-and-a-half hours.
Glaisher thought they'd got to 37,000 feet...
This was a prodigious feat and scientifically significant.
Glaisher found that the higher he went,
the less moisture there was in the atmosphere.
This discovery alone
advanced our understanding of how and where clouds form.
These Victorians were astonishing figures.
On the 5th September 1862,
one of the greatest Victorian journeys of exploration took place,
and Glaisher and Coxwell rose seven miles
to study the moisture content of the air.
Victorian scientists not only advanced our understanding of rain,
they invented ways to protect us from its ill effects -
inventions that would transform British life forever.
People were afraid of the rain, in an odd way.
There was an absolute conviction that getting wet you would,
to use the phrase, catch your death.
Posh ladies didn't go out and get wet, unless,
as in Sense and Sensibility,
they were in terrible emotional turmoil.
-She's gone out walking.
-The devil knows which way she went.
The first waterproof fabric in this country is eternally associated
with Macintosh, a Scottish inventor,
a Scottish chemist who found a way of sandwiching rubber
between two sheets of cloth
and was therefore able to make waterproof clothing,
which was a revelation.
People didn't have to get soaked and stay soaked.
You could go for a ride in the country.
You could ride through a shower, arrive at your destination,
take your coat off and you were dry.
This was a novelty at the beginning of the 19th century
and through the 19th century these materials developed enormously,
right up to the present day.
Macintosh's amazing invention
led to a booming industry for rainwear.
Let it rain, let it blow.
When you outdoor-type dolls doll up in Aquatogs,
you are snugly stylish and stylishly snug.
With waterproof clothing, people no longer needed to fear the rain,
they could celebrate it in style.
# Pitter patter patter
# Pitter patter patter It feels like rain
# Let it pitter patter Let it pitter patter
# Don't mind the rain... #
Around this time there was an invention
that had even more impact on daily life in Britain
and indeed around the world.
It came from another Scottish pioneer, John McAdam.
By the late 18th century,
British roads were in a state not much different than,
or perhaps notably worse than, when the Romans left.
So that journeys,
you would have to budget twice as long in winter
to make any journey than you would in summer because of the rain.
The roads would simply decay into swamps.
At the end of the 18th century, McAdam, a Scottish businessman,
had the leisure to experiment with a thing that fascinated him -
how do you make a good road surface?
And laid a road, which was a huge success.
It was built on very simple principles.
You banked up the road
and then you created a surface of tiny chips of stone,
which would, with the action of the carriages passing over it,
be broken down into a very fine hard surface,
which in fact was relatively waterproof and that's rainproof.
That's the key here.
McAdam's roads were so successful
that we still use the same principles today.
Small chips are pressed together to form a rainproof layer.
These days we use bitumen and tar to increase waterproofing.
McAdam's road designs were one of the great accelerators of the economy.
They transformed life in the 19th century.
You were no longer trapped, as it were, behind a barrier of mud.
And that may sound like an exaggeration
but it's easy to find letters from the 18th century of people saying,
"Well, I'd love to come and visit you
"but the two miles from here to there are so muddy
"I couldn't possibly do it."
This is a way of beating the rain
and by laying a good road surface,
you're pushing the rain to one side,
you're eliminating it as a factor in your road
and that was a great leap.
He patented it and the world ignored it.
It was just too damn good.
It was copied everywhere.
If he'd got a penny, as it were,
for every yard of road he was responsible for,
he would have been the Bill Gates of his time.
We may not give it a second thought
but in Britain many of our great inventions
have been ways to protect ourselves from the rain.
Rain is certainly the mother of invention in Britain.
It's one of the big drivers for change.
People wanted to get out of the rain.
We have a huge variety of inventions -
from the car, which incidentally keeps us out of the rain,
the covered railway carriage keeps us out of the rain.
They're partly to keep water out.
It's a very big driver for modernity.
While we need protection from the worst rain can throw at us,
scientists today continue to research the mysterious process
that produces rain drops in clouds.
In the late 19th century,
scientists made a crucial breakthrough.
They realised that a key ingredient
essential for the production of rain drops is dust.
In warm climates,
water droplets condense around specks of dust in the atmosphere.
These are the seeds around which rain drops grow.
As water droplets collide with each other, they grow in size
until eventually they are heavy enough to fall as rain drops.
In the tropics, this is how rain usually forms and grows.
But in cooler climates, like ours in Britain,
rain forms in a very different way.
Dust particles are still the seed
but rain drops start their life as tiny ice crystals.
It's known as the cold rain process.
At Manchester University,
Clive Saunders conducts research into this cold rain process.
He uses a 40 foot chamber
to recreate conditions in a typical British rain cloud.
First, he fills the chamber with steam.
So this is the cloud generator
and we're going to use it to fill our chamber with cloud droplets,
which will take several minutes to fill up the chamber.
Then it will be simulating the inside of a cloud,
which is really rather like being in a fog.
Three floors up, Clive seals the top of the cloud chamber.
The temperature inside is now reduced to -15 degrees Centigrade
to simulate conditions inside a cloud.
Within the chamber are dust particles,
just as there would be in the atmosphere.
But because the temperature of the water vapour inside the chamber
is below freezing, ice crystals form around the dust particles.
As these ice crystals move around,
they attract more and more water vapour and grow in size.
Falling out of this chamber are millions of little ice crystals
and the whole of the cold room is full of ice crystals.
So they're growing now from me talking and breath producing vapour.
They're growing like snow.
So you can see diamond dust floating around.
In a real cloud the ice crystals grow into snow flakes
and begin the descent to earth as snow.
But unless the air temperature remains cold,
the flakes melt as they fall and become rain.
Most of the rain we experience in Britain starts its life as snow.
When scientists discovered
that dust particles are the key to growing rain drops,
they realised it might be possible
to artificially seed clouds to produce rain.
The breakthrough came in 1946, when American scientists found
that the chemical silver iodide produced particles
suitable for growing rain drops in clouds.
Cloud seeding works on the basis of the way rain drops
coalesce around small particles -
small, solid particles - in a cloud.
They're called condensation nuclei.
What you need to make rain drops is small pieces of dust, or pollen,
or salt and the more of those that you have in a cloud,
the more likely it is that you're going to get rain drops.
So the idea of cloud seeding was to artificially seed the cloud.
A rain cloud can contain more than eight million tonnes of water,
so the power to control when and where rain falls
has greatly interested governments and the military.
Could rain be used as a weapon of war?
the RAF conducted a cloud seeding experiment above Bedfordshire.
The results were inconclusive.
Cloud seeding was abandoned as a military option.
The American airforce seized on the potential of seeding in the '60s
and poured money into research.
During the Vietnam War,
the Pentagon was keen to use anything to give them an advantage
in the fight against the Vietcong, an elusive guerrilla army.
Their aim was to trigger rain
to fall on the Vietcong's key strategic supply routes
and in March 1967 this new weapon was put to the test
in operation Project Popeye.
Experiments continued for five years until 1972,
when a document was leaked to the press.
The public were outraged and the experiments were halted.
Yet today cloud seeding is carried out throughout the world.
The Chinese did it during the Olympic Games.
But scientists disagree about the effectiveness of cloud seeding.
It's been extremely difficult to show this works.
In fact, the random trials have shown -
as best we can see - that it doesn't work.
But in some countries of the world it still goes on
and in China there's more people trying to modify the weather
than there are trying to forecast it.
Despite our attempts to manipulate the rain,
we will never truly be the masters of it.
And climate change is cruelly exposing our lack of control.
Wild weather may not be a punishment from the gods
but we look to the heavens with increasing anxiety
as the character of British rain changes.
The existing forecasts about what climate change will do to Britain
tell us that we will have a lot of concentrated very bad weather.
How will we cope with that?
I think that we will struggle.
We need to overcome this idea
that we shouldn't have to accommodate ourselves to weather.
With climate change, the one prediction that we can make
with real confidence is that we expect rainfall to become heavier.
When it rains, we'll get more large precipitation events.
The warmer air will actually be able to hold more water vapour,
so we can expect heavier rainfall.
Lewes, in East Sussex, thought they had a solution to heavy rain.
Sitting on the flood plain of the River Ouse,
the town centre had flooded in the past,
but since then defences had been built, banks strengthened,
and walls were put in place along the river.
But in the year 2000 it became clear that people of Lewes
had been enjoying a false sense of security.
Lewes had a very big flood in the 1960s and the response then was,
"We'll build up our defences so that can't happen again."
And yet along comes a pretty freaky series of weather events
and the whole valley above the town floods
and this water is then forced through Lewes.
Well, we had a month's rainfall in 48 hours
and then suddenly all hell broke loose
because it came through the ground.
It came up through the tarmac, through the drains,
and we were six foot under water in the space of 15 minutes.
I don't think we were prepared for the magnitude of the flood.
What happens is that the water gets over the flood barriers,
inundates the town and can't get out again.
And worse than that, of course,
because of this conviction you could defend yourself against flooding,
the Fire Service installed their headquarters behind the defences.
These were now flooded and the water was trapped for days.
TV: The town is completely cut in two.
Waters rose so fast, even the emergency services were caught out.
Ambulances and police cars have been replaced with boats.
Emergency services struggled to cope with the rain.
At Harvey's Brewery,
Miles Jenner was working hard to salvage the business.
The brewery itself we evacuated by lifeboat
because we'd stayed to the bitter end and they sent in a life raft
and our staff were ferried out through the casks
that were bobbing in the water and up to dry land.
No-one died in these floods
but over 800 homes and businesses were devastated.
More than £80 million of damage was caused
by one of the heaviest rainfalls in the area.
Flood plains are there for a purpose.
They're to allow rivers to flood, as the name suggests,
when there's a lot of rainfall, and that's why they're flat.
That means developers like to build on them because it's easy,
until a flood comes along.
I think the lessons learned in Lewes are very hard ones
because Lewes faced a choice. It was expanding.
It could build up onto the South Downs.
Well, who wants that? Or it could build down onto the flood plain.
It built down onto the flood plain with big flood barriers
and still it was caught.
So the lesson from that is,
do you build ever bigger flood defences at enormous cost,
or do you try and plan to expand your populations somewhere else,
because it is a natural bottleneck.
There will always be a danger of flooding.
MUSIC: "I Can't Stand The Rain" by Ann Peebles
If we ever believed we could master the rain,
then recent summers have shattered our complacency.
In 2007, extreme rainfall led
to the wettest May to July since 1766.
Tewkesbury in Gloucestershire was deluged.
There have always been floods here -
a fact taken into account
when the builders constructed the town around the abbey.
They knew that Tewkesbury floods and so they were very clever,
particularly the monks, of building the abbey
exactly where it should be built, which is on dry land.
The lessons of the past were forgotten or ignored.
And in 2007, when rain flooded the town centre,
one building to remain above the waterline was the medieval abbey.
It looked like an ark. And it was treated as an ark.
People actually came and sought sanctuary here,
which is what a church should be able to offer - sanctuary.
I think when the rains come, people are looking over their shoulder.
There's a sense of fear around that all this could happen again.
The weather that we're experiencing at the moment
is reminding us that we are not above nature
but we're an essential part of it.
I think, especially over the last two decades,
we've become increasingly disconnected from the weather
and from the climate as well.
We no longer know, as a nation, what normal British weather is.
And every time something unusual comes along,
though we may have had it many times in the past,
everybody wants an explanation. They want to point the finger.
If it impinges on their lives and interrupts their day-to-day lives,
they want somebody to blame for it.
Somebody has to do something about this.
There's gotta be some precaution they can take about this flooding.
It's happened three times this year.
We were always a bit too complacent about rain.
I think we did get an idea
that we were above weather and we never were.
With the arrival of global warming,
we're now slipping back into a time of greater uncertainty about it
and a fear that we will have to alter our behaviour.
We're going to have reckon with the fact that rain is back,
as a threat to us, in a way that the Victorians
and the scientists of the 20th century
thought they might eliminate.
# In each and every life
# Some rain has got to fall
# But too much of that stuff has fallen into mine
# Some folks can lose the blues in their heart
# But when I think of you another shower starts
# Into each life some rain must fall
# But too much has fallen in mine. #
Documentary series about the weather. The rain is an essential part of being British, giving us the English lawn, the sliding tackle and endless grounds for complaint, but what do we really know about it?
The programme uncovers the true shape of a raindrop, shows how and why rain falls, and tells remarkable stories of how we have adapted or succumbed to this elemental force of nature, such as James Glaisher's seven-mile hot-air balloon ascent in 1862, and how Charles Macintosh invented the waterproof coat.
The Victorians believed that they could master the rain and push it aside, but today climate change threatens us with rain that is wilder and more unpredictable than ever.