0:00:03 > 0:00:05The monsoon.
0:00:05 > 0:00:06THUNDER CRASHES
0:00:06 > 0:00:09The greatest weather system on Earth.
0:00:15 > 0:00:17The giver of life.
0:00:17 > 0:00:19And the destroyer.
0:00:23 > 0:00:25Shaping magical lands,
0:00:25 > 0:00:28from the Himalayas
0:00:28 > 0:00:30to Australia.
0:00:31 > 0:00:34Its impact felt by giants,
0:00:34 > 0:00:36the exquisite,
0:00:36 > 0:00:38and the bizarre.
0:00:40 > 0:00:42Where spectacular nature
0:00:42 > 0:00:46meets the planet's most vibrant cultures.
0:00:50 > 0:00:55Our story begins when all of life is waiting.
0:00:57 > 0:01:01It's a time when wildlife is pushed to extremes.
0:01:07 > 0:01:12A time when ancient cultures anxiously await the great rains
0:01:12 > 0:01:16to deliver the wonders of the monsoon.
0:01:16 > 0:01:18THUNDER CRASHES
0:01:27 > 0:01:29Across a vast area of the globe,
0:01:29 > 0:01:32from India to Australia,
0:01:32 > 0:01:34life is dominated
0:01:34 > 0:01:37by an immense weather system.
0:01:39 > 0:01:40The monsoon.
0:01:44 > 0:01:49Throughout the year, unimaginable quantities of water
0:01:49 > 0:01:52are moved about this swathe of our planet in rhythms
0:01:52 > 0:01:57sometimes unpredictable and mysterious.
0:02:02 > 0:02:06The monsoon delivers deluge,
0:02:06 > 0:02:10and with it the miracle of rejuvenation.
0:02:23 > 0:02:27But the monsoon can also bring drought.
0:02:29 > 0:02:33Such extremes test the endurance of every creature
0:02:33 > 0:02:35and everybody.
0:02:37 > 0:02:39We begin our journey
0:02:39 > 0:02:43in the far southern extreme of the monsoon world.
0:03:00 > 0:03:03It's the dry season in Northern Australia.
0:03:07 > 0:03:09BUZZING
0:03:17 > 0:03:20It's been six long months without rain.
0:03:31 > 0:03:36But there is an escape from this dry and thirsty land.
0:03:41 > 0:03:43The Roper River.
0:03:44 > 0:03:48Fed by underground springs, it flows throughout the year.
0:03:52 > 0:03:55A vital refuge for a small mammal
0:03:55 > 0:03:57with an intense dislike for the sun.
0:04:00 > 0:04:02The little red flying fox.
0:04:05 > 0:04:09These bats are waiting for monsoon rains,
0:04:09 > 0:04:13but now it's reached 38 degrees Celsius.
0:04:15 > 0:04:18Just a few degrees more, and they will die.
0:04:21 > 0:04:23THEY SCREECH
0:04:23 > 0:04:25Squabbles break out for shade.
0:04:32 > 0:04:34They are dehydrating.
0:04:34 > 0:04:39300,000 bats are desperate for water.
0:04:52 > 0:04:55Only the Roper River can save them.
0:05:04 > 0:05:08By soaking their chests, they can collect a little water
0:05:08 > 0:05:09to lick off back at the roost.
0:05:17 > 0:05:21But this is probably the most dangerous thing they'll ever do.
0:05:23 > 0:05:24SPLASH
0:05:34 > 0:05:37Australian freshwater crocodiles.
0:05:38 > 0:05:40Warmed by the summer heat,
0:05:40 > 0:05:43they are at their most alert.
0:05:56 > 0:06:00A crocodile's jaws snap shut in the blink of an eye.
0:06:03 > 0:06:05The bats' reactions...
0:06:07 > 0:06:09..must be quicker.
0:06:16 > 0:06:19They must choose a spot, and run the gauntlet.
0:07:17 > 0:07:20The survivors will brave the river every day
0:07:20 > 0:07:22until the monsoon rains break.
0:07:25 > 0:07:27Which must be soon.
0:07:35 > 0:07:39Australian Aboriginals call this time of the year Gunumeleng -
0:07:41 > 0:07:42the pre-monsoon.
0:07:45 > 0:07:49It's a tense, menacing time that can last for weeks,
0:07:51 > 0:07:54and which brings an unexpected danger.
0:07:57 > 0:07:59Dry lightning.
0:08:03 > 0:08:07The spark that ignites the "fire devil".
0:08:23 > 0:08:25This raging tornado of fire
0:08:25 > 0:08:28can grow to more than 100m high.
0:08:28 > 0:08:32It incinerates everything in its path.
0:08:35 > 0:08:39At its core, the temperature can reach over 1,000 degrees.
0:08:42 > 0:08:46From all around, air is sucked into the furnace,
0:08:46 > 0:08:47feeding the flames,
0:08:47 > 0:08:50before being blasted high into the sky.
0:09:02 > 0:09:05It's by a similar process of heat rising
0:09:05 > 0:09:09that right now the monsoon winds are being drawn towards Australia.
0:09:13 > 0:09:16But on a scale that's continental.
0:09:20 > 0:09:24The entire landmass is now a vast hot-plate.
0:09:26 > 0:09:29It heats the air above, causing it to rise.
0:09:29 > 0:09:34This sucks in more air from all around.
0:09:34 > 0:09:36These are the monsoon winds.
0:09:36 > 0:09:38WINDS BLOW
0:09:38 > 0:09:41And as they hit Australia's coast,
0:09:41 > 0:09:44great storms begin to build.
0:09:51 > 0:09:54As the humid air hits the heated land,
0:09:54 > 0:09:56it's thrust upwards,
0:09:56 > 0:09:58rapidly cooling,
0:09:58 > 0:09:59condensing...
0:10:02 > 0:10:06..and forming clouds taller than the world's highest mountains.
0:10:14 > 0:10:16Giant cumulonimbus -
0:10:16 > 0:10:20the biggest and most powerful clouds on the planet.
0:10:26 > 0:10:30Inside, vast electric charges build
0:10:30 > 0:10:32on a monumental scale.
0:10:46 > 0:10:49WINDS HOWL
0:10:51 > 0:10:55The energy released from just a single storm cell
0:10:55 > 0:10:59can be equivalent to an exploding atom bomb.
0:11:05 > 0:11:10They can let fly over 1,000 lightning strikes an hour.
0:11:21 > 0:11:24With every discharge, the air around explodes
0:11:24 > 0:11:26at over 25,000 degrees,
0:11:26 > 0:11:30four times hotter than the surface of the sun.
0:11:41 > 0:11:42FLYING FOXES SCREECH
0:11:52 > 0:11:55At last, the flying foxes are free.
0:11:58 > 0:12:01No longer tied to the crocodiles' river,
0:12:01 > 0:12:04they can now return to their nomadic life
0:12:04 > 0:12:06and disperse across the outback.
0:12:09 > 0:12:11For the next few months,
0:12:11 > 0:12:13one of the biggest weather systems on Earth
0:12:13 > 0:12:15sits over Northern Australia,
0:12:15 > 0:12:18transforming the land...
0:12:19 > 0:12:21..and stirring dragons.
0:12:34 > 0:12:36A frill-necked lizard.
0:12:37 > 0:12:41He's endured the dry-season heat and lack of food
0:12:41 > 0:12:45by drifting in and out of a state of suspended animation.
0:12:51 > 0:12:55But the monsoon rains have triggered a bounty.
0:13:04 > 0:13:07This is his chance.
0:13:07 > 0:13:12He must cram a year of life into these few short months.
0:13:22 > 0:13:25But he's not the only predator the monsoon wakes.
0:13:27 > 0:13:31The black-headed python has a taste for lizards.
0:13:33 > 0:13:35HISSING
0:13:39 > 0:13:41His frill is a bluff,
0:13:41 > 0:13:44to look big and ferocious.
0:13:44 > 0:13:46But if that doesn't work,
0:13:46 > 0:13:49he's off.
0:13:51 > 0:13:55He sprints so fast that his upper body lifts off.
0:13:58 > 0:14:01At speeds of up to ten miles an hour,
0:14:01 > 0:14:03no snake is going to catch him.
0:14:12 > 0:14:16This is a lizard that lives life in the fast lane.
0:14:17 > 0:14:21At least while the southern monsoon is overhead.
0:14:27 > 0:14:301,000 miles to the north,
0:14:30 > 0:14:33on a remote and tiny island,
0:14:33 > 0:14:36the rains have triggered another extraordinary emergence.
0:14:39 > 0:14:42One of the greatest wonders of the monsoon.
0:14:49 > 0:14:50Across the island,
0:14:50 > 0:14:54the forest floor is erupting.
0:14:58 > 0:15:02Over 40 million burrows are opening up.
0:15:09 > 0:15:13The red crabs of Christmas Island.
0:15:20 > 0:15:23For most of the year, they hid below ground,
0:15:23 > 0:15:26feeding on rotting leaves.
0:15:27 > 0:15:31But now, with the monsoon and rising humidity,
0:15:31 > 0:15:34they begin to march.
0:15:37 > 0:15:40It's time to spawn.
0:15:48 > 0:15:52The forest is a colossal assault course.
0:16:02 > 0:16:07And the neighbours are indignant at the sudden swarm.
0:16:07 > 0:16:09SQUAWKING
0:16:18 > 0:16:20BUZZING
0:16:20 > 0:16:25A nesting booby is best avoided.
0:16:31 > 0:16:34But the crabs face a more insidious danger.
0:16:36 > 0:16:38Suffocation.
0:16:43 > 0:16:45Crabs, even land crabs,
0:16:45 > 0:16:49breathe with gills that must remain moist.
0:16:51 > 0:16:55They can only attempt this journey when the monsoon brings damp air,
0:16:55 > 0:16:59but every time the clouds part, water evaporates,
0:16:59 > 0:17:03and it becomes increasingly difficult to breathe.
0:17:10 > 0:17:13But that's not the end of their troubles.
0:17:17 > 0:17:19Monster-sized robber crabs.
0:17:20 > 0:17:23Their legs span up to a metre across,
0:17:25 > 0:17:28and with little competition,
0:17:28 > 0:17:31they have become the top predator.
0:17:47 > 0:17:49CRUNCHING
0:18:15 > 0:18:18But no matter how many they kill,
0:18:18 > 0:18:20they won't dent red crab numbers.
0:18:22 > 0:18:24There are just too many of them.
0:18:42 > 0:18:45The island's entire population,
0:18:45 > 0:18:48over 45 million of them,
0:18:48 > 0:18:50are on the march.
0:19:03 > 0:19:05Journey's end.
0:19:13 > 0:19:14It's more than two weeks
0:19:14 > 0:19:19since these crabs left the darkness of their burrows.
0:19:19 > 0:19:22And this is why they've come so far.
0:19:27 > 0:19:31Tonight, when the tide is at its highest,
0:19:31 > 0:19:36billions of red crab eggs will be released into the sea.
0:19:42 > 0:19:44Mission complete,
0:19:44 > 0:19:47they'll all return to their forest burrows
0:19:47 > 0:19:50before the island dries out once more.
0:19:52 > 0:19:55It's only down to the moisture brought by the monsoon
0:19:55 > 0:19:59that these crabs can make their incredible journey.
0:20:15 > 0:20:19While the colossal weather system revives Australia
0:20:19 > 0:20:22and its neighbouring islands, further to the north,
0:20:22 > 0:20:26it's making life surprisingly difficult.
0:20:29 > 0:20:32Monsoon winds draw moist air away,
0:20:32 > 0:20:37creating a dry season in one of the most unexpected places.
0:20:37 > 0:20:40Southeast Asia's equatorial islands.
0:20:47 > 0:20:50With daily rainfall for most of the year,
0:20:50 > 0:20:53this is one of the warmest and wettest regions in the world.
0:20:58 > 0:21:03The annual rainfall for some islands can be as much as six metres.
0:21:04 > 0:21:07But even here, it's seasonal.
0:21:10 > 0:21:12While Australia is having downpours,
0:21:12 > 0:21:17the island of Sumatra has only the lightest showers.
0:21:21 > 0:21:24It's perfect weather for a baby orang-utan
0:21:24 > 0:21:26to practise a useful skill.
0:21:30 > 0:21:33Making a leaf umbrella.
0:21:36 > 0:21:40During the wet season, it will be an essential accessory.
0:21:42 > 0:21:44He hasn't quite perfected it yet.
0:21:48 > 0:21:49But that's fine.
0:21:49 > 0:21:51He has time.
0:21:56 > 0:22:00Even so, the dry season creates a problem for Mum.
0:22:06 > 0:22:09She has to find food for both of them,
0:22:09 > 0:22:11but during the dry season,
0:22:11 > 0:22:16fewer trees fruit, and they're usually great distances apart.
0:22:27 > 0:22:30She must take her son on a long and difficult journey
0:22:30 > 0:22:32through the treetops.
0:22:42 > 0:22:45Their search will cover many miles of canopy,
0:22:45 > 0:22:47and she can't afford to get it wrong.
0:22:54 > 0:22:56But she has a plan.
0:22:57 > 0:23:00She knows exactly where to head.
0:23:04 > 0:23:09She holds a mental map of almost 1,000 hectares of rainforest.
0:23:11 > 0:23:13But also, quite remarkably,
0:23:13 > 0:23:18she has a diary of exactly which trees are fruiting
0:23:18 > 0:23:19and when.
0:23:26 > 0:23:31She times her journey through the forest precisely.
0:23:33 > 0:23:35A fig tree she knows well.
0:23:36 > 0:23:39Its fruit, perfectly ripe,
0:23:39 > 0:23:41just as she knew it would be.
0:23:54 > 0:23:59Her memory map is vital for surviving lean times,
0:23:59 > 0:24:02and now she's passing that knowledge on to her son.
0:24:02 > 0:24:06He'll spend up to ten years with Mum,
0:24:06 > 0:24:10piecing together his own map and diary.
0:24:25 > 0:24:29It will be her legacy, and his survival kit.
0:24:32 > 0:24:34When the monsoon rains return,
0:24:34 > 0:24:37fruit will be widely available again.
0:24:39 > 0:24:41But there are rogue years,
0:24:41 > 0:24:46when the monsoon is so weak that it fails to bring rain.
0:24:46 > 0:24:48Yet what sounds like a disaster
0:24:48 > 0:24:52is crucial for the survival of a key forest species.
0:24:54 > 0:24:59Dipterocarp trees, some up to 70 metres tall.
0:25:00 > 0:25:04And as the forest dries out, something magical happens.
0:25:04 > 0:25:09They all flower and fruit at the same time.
0:25:17 > 0:25:22Which means all their winged seeds ripen
0:25:22 > 0:25:24then drop together.
0:25:43 > 0:25:48Each tree sheds as many as 20 million seeds,
0:25:48 > 0:25:51so there are billions carpeting the forest floor.
0:26:02 > 0:26:03Though triggered by
0:26:03 > 0:26:06the unpredictable failure of the monsoon,
0:26:06 > 0:26:12the reason for this spectacle is the trees' greatest foe.
0:26:14 > 0:26:18A tiny weevil, less than the width of a matchstick.
0:26:22 > 0:26:25This is a voracious seed predator.
0:26:25 > 0:26:29But because the trees have not fruited for several years,
0:26:29 > 0:26:31the weevil population has starved,
0:26:31 > 0:26:34and has been kept in check.
0:26:40 > 0:26:42By fruiting now, as one,
0:26:42 > 0:26:46the remaining weevils are swamped by a glut of food.
0:26:53 > 0:26:58Guaranteeing that many of the seeds will survive, and germinate.
0:27:01 > 0:27:04The trees have used the rare failed monsoon
0:27:04 > 0:27:07as a cue to outwit their number-one enemy.
0:27:17 > 0:27:21But there was once a time when the monsoon cycles mysteriously changed,
0:27:21 > 0:27:25and weakened, for almost a century.
0:27:31 > 0:27:37In the forests of Cambodia lie the remains of a once-thriving city.
0:27:41 > 0:27:44The temple of Angkor Wat.
0:27:49 > 0:27:51Nearly 1,000 years ago,
0:27:51 > 0:27:56Angkor was the pre-industrial world's greatest city,
0:27:56 > 0:28:00built on the bounty of the monsoon.
0:28:10 > 0:28:14Superb engineers constructed vast reservoirs
0:28:14 > 0:28:17to collect monsoon waters, used for irrigation
0:28:17 > 0:28:21and pushing food production to the maximum.
0:28:28 > 0:28:33At its peak, over a million people lived in Angkor.
0:28:33 > 0:28:35But then the monsoon weakened,
0:28:35 > 0:28:38causing a cycle of severe droughts
0:28:38 > 0:28:41that lasted nearly 100 years.
0:28:48 > 0:28:54Drought brought famine, and an end to wealth and prosperity.
0:29:01 > 0:29:04Angkor's population collapsed.
0:29:11 > 0:29:13The kingdom fell,
0:29:13 > 0:29:17its buildings consumed by the forest.
0:29:24 > 0:29:30Its people had created a system that relied totally on the monsoon.
0:29:33 > 0:29:38Too fragile to survive such drastic change.
0:29:46 > 0:29:49Today, over half the world's population
0:29:49 > 0:29:52are dependent on its fickle nature.
0:29:54 > 0:29:56Each year, in India,
0:29:56 > 0:30:01people's hopes focus on whether the rains will come to them.
0:30:04 > 0:30:08An explosion of colour welcomes spring
0:30:08 > 0:30:11as rainbow play-fights take to the streets
0:30:11 > 0:30:15in the joyous celebration of Holi.
0:30:24 > 0:30:27It marks the end of the dry winter
0:30:27 > 0:30:32and anticipates what all hope is soon to come.
0:30:36 > 0:30:39In Mathura Temple in northern India,
0:30:39 > 0:30:43families gather in a centuries-old tradition.
0:30:46 > 0:30:51It honours a symbolic victory of the future over the past
0:30:51 > 0:30:53and good over evil.
0:30:57 > 0:31:01For this, they call on the monsoon.
0:31:01 > 0:31:04INDIAN MUSIC PLAYS
0:31:27 > 0:31:31Water is coloured with the spring flowers of the forest.
0:31:31 > 0:31:34Symbolic of the monsoon rains,
0:31:34 > 0:31:37it washes away the dust of the dry season
0:31:37 > 0:31:39and the old year.
0:31:41 > 0:31:45This is a rebirth for everyone.
0:32:10 > 0:32:13But underlying the colour and good humour
0:32:13 > 0:32:16is something far more serious.
0:32:18 > 0:32:22Economic success and even a family's very survival
0:32:22 > 0:32:24depends on the rains coming.
0:32:30 > 0:32:32What controls their future
0:32:32 > 0:32:35lies over the northern border of their huge country.
0:32:46 > 0:32:50The Himalayas - the highest peaks on Earth.
0:32:54 > 0:32:59And beyond, the great Tibetan Plateau.
0:33:02 > 0:33:05This is the other driver of the monsoon,
0:33:05 > 0:33:09even more powerful than Australia.
0:33:11 > 0:33:15As the Plateau heats up in spring, hot air rises,
0:33:15 > 0:33:20drawing in monsoon winds from thousands of miles away.
0:33:20 > 0:33:24From far beyond the southern tip of India.
0:33:33 > 0:33:36The winds pull at the surface of the Indian Ocean,
0:33:36 > 0:33:39creating currents so powerful
0:33:39 > 0:33:42that even the waters of the deep sea turn to follow,
0:33:44 > 0:33:48bringing great changes beneath the waves.
0:34:00 > 0:34:03In the Maldives Archipelago,
0:34:03 > 0:34:05an unusual gathering takes place,
0:34:05 > 0:34:09triggered by the pull from the distant Tibetan Plateau.
0:34:17 > 0:34:21A giant manta ray, almost four metres across.
0:34:26 > 0:34:29They're normally solitary wanderers,
0:34:29 > 0:34:34but now many arrive together in one small, shallow bay.
0:34:39 > 0:34:42They're here for a feast.
0:34:57 > 0:35:00Mantas feed on microscopic plankton,
0:35:00 > 0:35:02relatively scarce in the tropics.
0:35:02 > 0:35:04But the monsoon winds
0:35:04 > 0:35:08pull up cold, nutrient-rich water from the depths,
0:35:08 > 0:35:10thick with plankton,
0:35:10 > 0:35:14trapping it for just a few hours in the confines of this bay.
0:35:20 > 0:35:23Remarkably, the mantas know when to be here
0:35:23 > 0:35:25almost to the minute.
0:35:27 > 0:35:30Just how they know is still a mystery.
0:35:41 > 0:35:43For a fleeting moment,
0:35:43 > 0:35:48it's the greatest gathering of giant mantas in the world,
0:35:48 > 0:35:54and all brought about by the winds blowing towards the Tibetan Plateau.
0:36:08 > 0:36:12After just a few hours, the plankton disperses,
0:36:12 > 0:36:17and conditions won't be as good again until next year.
0:36:24 > 0:36:27Above the waves, through the monsoon season,
0:36:27 > 0:36:31the winds hold steady and strong,
0:36:31 > 0:36:33heading towards India.
0:36:37 > 0:36:41It's April in Kanha, northern India,
0:36:41 > 0:36:44and the forest wakes to a new summer day.
0:36:49 > 0:36:52Soon, it will be unbearably hot.
0:36:54 > 0:36:57But there's a sure sign that change is coming.
0:36:57 > 0:36:59PEACOCK CALLS
0:37:01 > 0:37:03According to local folklore,
0:37:03 > 0:37:08the peacock's call means the monsoon is just weeks away.
0:37:17 > 0:37:21Right now, his one desire is a partner.
0:37:26 > 0:37:30But peahens aren't so easily impressed.
0:37:42 > 0:37:44If only he could mate now,
0:37:44 > 0:37:47his eggs would hatch just in time for the monsoon.
0:38:19 > 0:38:21PEACOCK CALLS
0:38:23 > 0:38:27The hormones are clearly clouding his judgment.
0:38:29 > 0:38:32PEACOCK CALLS
0:38:40 > 0:38:46By mid-morning, it's just too hot for such flamboyance.
0:38:46 > 0:38:49The forest is drying out.
0:38:49 > 0:38:51Toughest, perhaps, for the chital deer.
0:38:51 > 0:38:58The ground is parched, and food out of reach for even the tallest stags.
0:39:01 > 0:39:03But they've learned that right now,
0:39:03 > 0:39:06it pays to hang out with fellow forest-dwellers.
0:39:06 > 0:39:09Hanuman langur monkeys.
0:39:11 > 0:39:14Mahua trees produce their strangely fleshy flowers
0:39:14 > 0:39:20before the rains, just when the animals most need them.
0:39:23 > 0:39:26There's enough that the monkeys can take their fill
0:39:26 > 0:39:28and leave the rest.
0:39:37 > 0:39:41Sticking with the langurs means the chital can keep their strength.
0:39:41 > 0:39:45But there's also security in their combined numbers.
0:39:49 > 0:39:50GROWLING
0:39:54 > 0:39:57A tiger mother with two rapidly growing cubs.
0:40:06 > 0:40:09They're bouncing with energy.
0:40:15 > 0:40:18Not even the heat of the day stops their play.
0:40:41 > 0:40:43Despite the invitation,
0:40:43 > 0:40:47their mother is more intent on keeping cool
0:40:47 > 0:40:49than joining in.
0:40:49 > 0:40:55Experience tells her it's only going to get hotter.
0:41:01 > 0:41:05Right across India, temperatures are soaring.
0:41:07 > 0:41:12It's June, and the monsoon should be here by now.
0:41:12 > 0:41:17Roads must be repaired before the expected floods.
0:41:17 > 0:41:19But will they come?
0:41:21 > 0:41:23The city waits.
0:41:26 > 0:41:28Traders monitor the market.
0:41:28 > 0:41:31When rains delay,
0:41:31 > 0:41:33food prices rocket.
0:41:33 > 0:41:38The impact of a failed monsoon will ripple across the entire world.
0:41:45 > 0:41:49With the monsoon already late and the stakes so high,
0:41:49 > 0:41:52it calls for desperate measures.
0:41:52 > 0:41:54CHANTING
0:43:01 > 0:43:03In a sacred ceremony,
0:43:03 > 0:43:08called upon only when fears of failure are greatest,
0:43:08 > 0:43:12holy Brahmins give voice to ancient Vedic texts
0:43:12 > 0:43:15that are learned by heart.
0:43:21 > 0:43:27They call on Varuna, the god of water.
0:43:27 > 0:43:28CHANTING
0:43:48 > 0:43:52This centuries-old ritual beseeches Varuna
0:43:52 > 0:43:55to deliver India from drought.
0:43:55 > 0:43:59Prayers to bring the life-giving monsoon.
0:44:10 > 0:44:12But will he answer?
0:44:22 > 0:44:26Outside, it's getting tougher by the hour.
0:44:29 > 0:44:32On northern Indian salt pans,
0:44:32 > 0:44:35the rains are now two weeks late.
0:44:36 > 0:44:41And for one family, the situation is becoming critical.
0:44:43 > 0:44:46New foals have been born to a herd of Asian wild ass,
0:44:46 > 0:44:52their birth timed to coincide with the usual arrival of the monsoon.
0:44:55 > 0:44:58All around, new grass should be growing,
0:44:58 > 0:45:02but the frazzled ground offers nothing.
0:45:06 > 0:45:11A mother struggles to provide her youngster with enough milk.
0:45:11 > 0:45:16And now, there's danger coming from within the herd.
0:45:19 > 0:45:25Rain or not, the stallion has one thing on his mind.
0:45:28 > 0:45:29HE HOWLS
0:45:50 > 0:45:51He can't delay.
0:45:51 > 0:45:55Breed now, and next year's foals will arrive on schedule,
0:45:55 > 0:45:59in time for a normal monsoon and its fresh grass.
0:46:26 > 0:46:29Right now, the mares have barely enough energy
0:46:29 > 0:46:33to care for this year's foals, let alone carry another.
0:46:37 > 0:46:41They'll resist, but there's nowhere else to go.
0:46:41 > 0:46:45The herd must endure the rising tensions.
0:46:47 > 0:46:48And wait.
0:47:00 > 0:47:02PANTING
0:47:07 > 0:47:09In Kanha, even the cubs are subdued.
0:47:12 > 0:47:15Yet despite the heat, the delayed rains
0:47:15 > 0:47:19have given their mother a distinct advantage.
0:47:25 > 0:47:31In the forest, the chital are tied to the last muddy water holes.
0:47:58 > 0:48:04The dry vegetation means that she is perfectly camouflaged.
0:48:27 > 0:48:31But chital have a keen sense of smell.
0:48:32 > 0:48:34CHITAL CALLS
0:48:47 > 0:48:50Langurs warn the rest of the herd.
0:49:18 > 0:49:21She's brought down a large stag -
0:49:21 > 0:49:25more than two days' food for her cubs.
0:49:31 > 0:49:35The late monsoon has been good to the tiger family.
0:49:35 > 0:49:37But prey will be much harder to catch
0:49:37 > 0:49:39when the rains eventually come.
0:49:48 > 0:49:52And there's a sign that they're finally here.
0:50:01 > 0:50:03THUNDER RUMBLES
0:50:03 > 0:50:06India has endured months of drought.
0:50:07 > 0:50:10Could the long wait be over?
0:50:19 > 0:50:23Come the deluge, the land will be green again.
0:50:23 > 0:50:25RAINDROPS FALL
0:50:27 > 0:50:31But the monsoon can bring both welcome relief
0:50:31 > 0:50:33and complete devastation.
0:50:42 > 0:50:49The only certainty is that all of life here is about to change.
0:51:00 > 0:51:05Across the series, the team's ambition was to film monsoon storms
0:51:05 > 0:51:07in all their glory.
0:51:10 > 0:51:13Some of the world's biggest and most powerful thunderstorms
0:51:13 > 0:51:15occur in Northern Australia.
0:51:17 > 0:51:21This is where the team joined one man who understands the ambition
0:51:21 > 0:51:22more than anyone.
0:51:23 > 0:51:28Murray Fredericks, ex-commando and world-renowned photographic artist.
0:51:29 > 0:51:34For him, capturing the perfect storm is about more than just the weather.
0:51:34 > 0:51:36It can't just be a shot of a storm.
0:51:36 > 0:51:38It's got to be a great landscape as well.
0:51:38 > 0:51:39It's got to be the whole image.
0:51:39 > 0:51:43And getting that quickly, somewhere you've never been before
0:51:43 > 0:51:46because the storm is taking you somewhere you've never been before,
0:51:46 > 0:51:47is a real challenge.
0:51:49 > 0:51:54The team are monitoring about 400,000 square miles,
0:51:54 > 0:51:57an area four times bigger than the UK.
0:51:59 > 0:52:03Typically, storms need hot ground and high humidity to power them.
0:52:09 > 0:52:11Professional storm-chaser Jacci Ingham
0:52:11 > 0:52:14is helping the team to narrow the search area
0:52:14 > 0:52:16and safely get close to a storm.
0:52:16 > 0:52:17So we're trying to anticipate
0:52:17 > 0:52:20theoretically what we think's going to happen today,
0:52:20 > 0:52:22based on what we just know from the models.
0:52:22 > 0:52:26Humidity is rising 600 miles to the west.
0:52:26 > 0:52:30It's a good sign. But even with the help of radar,
0:52:30 > 0:52:32the search area is still vast.
0:52:32 > 0:52:34The chances of us now saying,
0:52:34 > 0:52:37"The storm is going to happen there" is 1%, you know?
0:52:37 > 0:52:40So I think if we go, "It's there, there, there, there, there,"
0:52:40 > 0:52:43and we just know that's where we barrel on to...
0:52:43 > 0:52:46We always want to be ahead of it so it's coming towards us.
0:52:48 > 0:52:51To film a storm, they need to find one that's accessible.
0:52:53 > 0:52:55So the thing about Australia is,
0:52:55 > 0:52:57the roads just go on for ever and ever.
0:52:57 > 0:53:00And this is apparently a highway.
0:53:00 > 0:53:02To cope with the rough roads,
0:53:02 > 0:53:05they're using specially adapted long-range vehicles.
0:53:06 > 0:53:09It's a long day's drive,
0:53:09 > 0:53:13but eventually Jacci's predictions pay off.
0:53:17 > 0:53:19We've just driven right into the rain.
0:53:19 > 0:53:21This is it.
0:53:21 > 0:53:23This is the real thing.
0:53:23 > 0:53:26There's thunder, there's lightning, the road's flooded,
0:53:26 > 0:53:27I can barely see out of the window.
0:53:27 > 0:53:30We're driving further and further into the storm.
0:53:30 > 0:53:32Wow, did you see that?
0:53:32 > 0:53:36That lightning just hit almost... Just off the side of the road.
0:53:37 > 0:53:42Here, a single storm can dump as much as 12 billion tonnes of water.
0:53:42 > 0:53:45I can hear the lightning over there,
0:53:45 > 0:53:48so that's... The centre of the storm is rumbling there,
0:53:48 > 0:53:51and if we can get in front of the storm where the light's hitting it,
0:53:51 > 0:53:53we could get some nice shots.
0:53:53 > 0:53:57- RADIO:- 'On the left-hand side, guys, there's a nice cell there.
0:53:57 > 0:54:00'Looking good.'
0:54:03 > 0:54:06Out of the rain, the team head to a high point
0:54:06 > 0:54:09where they can capture the storm's final stages.
0:54:13 > 0:54:16But to capture a single ten-second time-lapse,
0:54:16 > 0:54:18they need the camera to run, free of water on the lens,
0:54:18 > 0:54:20for at least ten minutes.
0:54:37 > 0:54:40The team need to leave the cameras running
0:54:40 > 0:54:41until the last possible moment
0:54:41 > 0:54:43before the storm is on top of them.
0:54:46 > 0:54:49- Let's go!- I've got to get the other camera too. That was good.
0:54:51 > 0:54:54An encouraging start to the shoot -
0:54:54 > 0:54:56a spectacular curtain of rain.
0:55:01 > 0:55:04What they need next is lightning.
0:55:06 > 0:55:09The land here is now wet and cold, but further west,
0:55:09 > 0:55:13it's still hot and humid, with storms looking likely.
0:55:16 > 0:55:20It's another 1,000 miles, and time is against them.
0:55:22 > 0:55:24We're trying to get into this more arid country,
0:55:24 > 0:55:27but this is as far as we go. There's no way round this river.
0:55:27 > 0:55:29- So what do we do now? - We turn around and go back -
0:55:29 > 0:55:31hope we've got enough fuel.
0:55:35 > 0:55:38By the time they catch up with the storm, it's dark.
0:55:41 > 0:55:42THUNDER CRASHES
0:55:42 > 0:55:46- Whoa!- It's absolutely going nuts.
0:55:46 > 0:55:48That sky is alive.
0:55:51 > 0:55:53Oh!
0:55:53 > 0:55:55It's a great light show.
0:55:55 > 0:55:57But for the perfect shot,
0:55:57 > 0:56:01Murray needs just enough daylight to illuminate the landscape.
0:56:01 > 0:56:03I hope this carries on.
0:56:03 > 0:56:07To get ahead, and ready for storms tomorrow,
0:56:07 > 0:56:09they're pushing even further west.
0:56:16 > 0:56:20The journey eventually brings them to the spectacular landscape
0:56:20 > 0:56:22of the Kimberleys.
0:56:25 > 0:56:29The humidity and temperature have been building here for days.
0:56:34 > 0:56:36I've got one straight ahead. Keep coming, guys.
0:56:37 > 0:56:39That's just stunning.
0:56:39 > 0:56:42RADIO:
0:56:53 > 0:56:55OK.
0:56:58 > 0:57:01A thunderhead is forming.
0:57:01 > 0:57:05The bigger it grows, the more static electricity builds up
0:57:05 > 0:57:07and the more chance of lightning.
0:57:07 > 0:57:11There's a shot, as tight as we can get through to that mountain range,
0:57:11 > 0:57:14through the saddle there between those two hills.
0:57:14 > 0:57:16Lightning keeps coming down at exactly the same point.
0:57:22 > 0:57:24ALL: Whoa!
0:57:26 > 0:57:28THUNDER CRASHES
0:57:30 > 0:57:31THEY WHOOP
0:57:31 > 0:57:33Look at that!
0:57:38 > 0:57:41I'm a little bit scared, now, what do you think?
0:57:41 > 0:57:43Never show fear to the storm.
0:57:43 > 0:57:45Whoa!
0:57:45 > 0:57:47I've never seen anything like that!
0:57:48 > 0:57:50It couldn't have actually worked out better.
0:57:50 > 0:57:52It's a beautiful shot.
0:57:52 > 0:57:55Good day, really, really lucky. Stunning.
0:57:55 > 0:57:57These images help to tell the story
0:57:57 > 0:58:00of the monsoon's arrival in Australia.
0:58:00 > 0:58:04For the monsoon team, though, this is just the beginning.
0:58:09 > 0:58:11Next time...
0:58:12 > 0:58:13..deluge.
0:58:18 > 0:58:20Flood.
0:58:22 > 0:58:25The monsoon at its most extreme.
0:58:28 > 0:58:30Those that survive
0:58:30 > 0:58:34must now grasp the opportunity to prosper...
0:58:35 > 0:58:37..from life-giving waters.