Original subtitles

Pounding rain,

ferocious winds and surging waves.

Tropical storms are a deadly disaster that affect millions,

causing damage, death and destruction in their wake.

They just destroy everything in their path.

These things are... Are deadly.

They're-- In some cases they're unsurvivable.

Then the winds drop and calm descends.

Is it over?

The eye of the storm is a small oasis of calm

in the center of a tropical cyclone storm.

Found at the center, the eye is surrounded

by storm clouds, rain and wind.

Cyclones continuously move across the Earth's surface.

Any safety afforded by the eye of the storm

is only a temporary respite.

As the cyclone continues to track forward,

the eye moves on.

The safe zone shifts as the winds close in again

for a second dose.

Cyclones are among the most destructive

of natural disasters,

impacting millions of people

and causing billions of dollars of damage.

In this episode of Deadly Disasters,

we will discover how cyclones form

and why they are so deadly.

Experts will provide testimony

on the most catastrophic disasters of recent years.

We will look at storm case studies from around the globe.

In 2017, Cyclone Debbie

left no part of Australia unaffected.

We will see the reasons why it went on to become

one of the costliest cyclones in Australian history.

Most of my stuff got still left there.

And it'll all be gone.

The aftermath of cyclones can be just as deadly,

with whole populations of people affected

by the lack of food and medical supplies.

We will look at how the rescue efforts in Myanmar

were thwarted by its despotic rulers,

ensuring the outcome of Cyclone Nargis in 2008

was many times worse.

What can be expected when the unthinkable happens

and two major cyclones hit in a single season?

Southern Africa in 2019

faced up to this nightmare circumstance,

forced to deal with both Idai and Kenneth.

No food, no food, no food.

We will consider what happens

when a country struggling to deal with one disaster

gets hit with another.

We will look at how people adapt and respond to cyclones.

Our experts will also look at how our changing climate

has influenced the impact and outcome of these storms.

Cyclones, typhoons and hurricanes

are basically the same type of storm.

The different titles indicate

the storm's geographical location:

cyclones in the South Pacific and Indian Ocean,

hurricanes in the Atlantic and the eastern North Pacific

and typhoons in the western North Pacific.

Regardless of the title,

these tropical storms are a serious challenge

for anyone unlucky enough to be in their path.

Cyclones need very specific weather conditions to form.

A tropical cyclone is a large swirling storm

which is found usually between five degrees latitude

in either hemisphere

and approximately 20 to 30 degrees latitude.

A tropical cyclone is a low pressure storm

that forms over tropical or subtropical waters.

The storm winds circulate in a spiral,

clockwise in the Earth's southern hemisphere

and counterclockwise in the north.

The forces that are needed for them to form

means that they will only occur in areas in the tropics

away from the equator,

where there is a rotational effect in the winds.

They will only form where the ocean is warm.

And they will form where there is humidity in the atmosphere.

So where those conditions are right,

then a storm can be formed.

And it can grow and grow under its own power

and produce a devastating tropical cyclone.

Cyclones cover large areas,

enough to affect many millions of people

when they hit populated areas.

A cyclonic system is typically eight or 10 kilometers high

and around 480 to 640 kilometers across,

approximately the distance between London and Dublin.

Hurricanes and cyclones require several conditions to be right

in order for them to form.

Cyclones start in the tropics

over the warm ocean because heat and moisture are needed.

This sets up a flow of warm, moist air

that rises very quickly.

The rising air creates an area of low pressure at the surface

called a depression.

These tropical depressions only become tropical cyclones

when certain circumstances occur.

For instance, sea surface temperatures need to be

at least 27 degrees Celsius

to inject enough energy into the process.

Surface winds need to converge in the same area

from different directions.

This pushes the damp air upward,

allowing storm clouds to form.

The storm clouds need to rise vertically unimpeded

without being blown off course,

so wind shear needs to be minimal.

The twisting motion of the cyclones is generated

by the rotation of the Earth.

The depression needs to be

a specific distance from the equator

to provide a sufficient Coriolis force.

When all the weather conditions fall into this Goldilocks zone,

the winds accelerate into the spiral of a full-blown cyclone.

Its early genesis, it might be no more

than a severe thunderstorm,

or, as we would see it,

sort of a very cloudy, thundery, rainy area.

But if it gets those three conditions right,

it will intensify.

So when we are forecasting storms,

we can see them change their characteristics very quickly.

If they are traveling along a trajectory

which suddenly brings them into very, very warm ocean

or very moist atmospheres,

or suddenly the winds that might shear the storm

become very calm,

a tropical cyclone can intensify incredibly quickly.

In a matter of 24 hours,

it can change from a Category 1 to a Category 5.

Easily recognized from space,

cyclones form a cylinder of dense thundercloud

around a calm central eye.

The average eye of a cyclone is about 48 kilometers across.

The area is relatively calm,

a space where winds and rain abate.

The most extreme winds are found

on the edge of this area.

The eyewall is typically

the most destructive part of a cyclone.

Cyclones can be deadly

because they cause severe flooding.

And this flooding is over a fairly large area

and can be extreme,

in terms of 5, 6 meters of flooding in some cases,

and that catches people unprepared.

People underestimate cyclones

when they have not experienced a strong cyclone

in their region in the last, say, 20 years.

So when there is not the memory

of a strong cyclone in that region,

people tend to underestimate

how bad a cyclone is going to be.

Cyclones bring devastation

in the form of high winds, torrential rain

and coastal storm surges.

Australia, as a continent,

is close to the warm tropical waters of the South Pacific.

It's no stranger to the havoc that cyclones can unleash.

For a country that's used to extreme weather,

2017 was an exceptional year.

Tropical Cyclone Debbie was one of the worst storms

to hit Australia since records began.

Cyclones are given human's names

to allow for easy identification

of specific storms.

The practice stems from the 1950s.

Alternating male and female names are chosen

in alphabetic order.

On March the 23rd, off the coast of Queensland,

a tropical low pressure zone was detected.

Fed by high surface temperatures in the ocean,

it developed over the next three days

into a Category 4 cyclone.

Categories are an important indicator

of how dangerous a cyclone can be.

Cyclones are given a different numbered category

depending on their wind speeds.

Category 1 have sustained winds

above 119 kilometers per hour.

Category 2,

above 154 kilometers per hour.

Three, above 178 kilometers per hour.

Four, above 209.

And Category 5 have speeds

above 251 kilometers per hour.

The higher the category rating,

the more dangerous the cyclone potentially is.

Category 4 and 5 storms need to be taken very seriously indeed.

The strongest recorded winds from a tropical cyclone

are around 200 miles an hour,

sustained for about a minute.

And that is approaching the kind of winds and devastation

you would get from a tornado.

From March the 26th, 2017,

meteorologists tracked the westward progress of the storm

across the Pacific.

First landfall occurred

when Debbie hit the Whitsunday Islands

on March the 28th.

The Whitsunday Islands are normally a tropical paradise,

famous for their proximity to the Great Barrier Reef

and a popular tourist destination.

When Debbie hit the islands,

it was at Category 4 strength

with winds over 209 kilometers per hour.

The full force of the cyclone

was perfectly targeted on the islands,

with the eye of the storm passing directly overhead.

We were either just inside the red zone

or just outside it in the orange zone.

And that's like 170, 180 kilometer-an-hour winds.

That's-- That's bad. Heh, heh, that really is.

After hitting the Whitsunday Islands,

the storm continued towards the mainland

and made landfall at Airlie Beach, Queensland.

A peak storm surge of over two and a half meters

was recorded by Laguna Quays.

A storm surge is a rise in sea level

caused by a tropical cyclone.

Most deaths from tropical cyclones occur

from flooding due to storm surge.

And the second cause of death is flooding

due to freshwater rains and mudslides.

And the best way to prevent loss of life in storm surge

is evacuation and shelter.

And so people need time to be able to get to shelters

and there need to be shelters close enough

that people can get to them.

And the shelters need to be large enough

and adequate to survive the storm.

A storm surge occurs

where the sea level rises above its normal level,

often flooding low-lying areas.

Surges are caused by the low pressure,

high winds and high waves generated by the cyclone.

If a high tide coincides with the cyclone's landfall,

the waves can be even higher...

because the additional storm surge waters

flow on top of the high tide.

In coastal areas, storm surges are often

the greatest threat to life and property.

A cubic meter of water weighs about 1000 kilograms,

and surges are able to exert significant forces

against anything in their path.

Only the strongest buildings and flood defenses

can withstand the pounding of the water.

People caught in the initial surge

risk being washed away...

drowned, trapped in falling buildings,

or injured by moving debris.

Floods caused by storm surges

have the added complication that the seawater is saline.

The salt water flows inland,

poisoning wells, farmland

and seeping into the groundwater.

The groundwater salinity can last years,

causing havoc with water supplies

until it's eventually diluted enough by fresh rainwater.

Floodwaters can also overrun sewers,

spreading infectious disease.

Evidence of fecal contamination, such as E. coli,

as well as we've got evidence

of Streptococcus and Legionella.

These things, while they may be harmless

when floating around in floodwater,

if you were to get them into a wound or in your mouth

or on your food, could cause

some quite severe gastrointestinal illnesses.

Dealing with the sheer numbers of affected people

is one of the main logistical challenges

associated with cyclones.

All women and children, follow the lady!

Large numbers of transient people

can block transport routes

and then need quantities of food, medicine and shelter.

Flooding was expected in low-lying coastal areas.

Twenty-five thousand residents in the area of Airlie Beach,

Bowen and Proserpine were ordered to evacuate.

The same day,

Debbie made landfall in Queensland around 5 p.m.

with wind gusts of up to 262 kilometers per hour.

Boats were blown onto the shore.

Gusts ripped roofs off buildings,

leveled walls,

and mature trees were uprooted.

The storm behaved like a battering ram

as it smashed through the town.

Heavy rainfall continued,

triggering dramatic flooding.

One measuring station recorded 646 millimeters of rain

in a single 24 hours.

The water went up to the top of the windows,

so everything I couldn't get up out of it would be gone.

For the next two days,

Cyclone Debbie continued to push on

across the countryside...

creating a disaster zone...

across a 1400 kilometer-wide stretch

of the Australian landscape.

Cyclone Debbie was a very large system that moved slowly.

It took a long time to pass.

Areas underneath were directly in the storm for longer

than they would otherwise be in a typical cyclone.

Fortunately, there were no immediate deaths

in the strike zone,

although the eventual death toll

was at least 10 people.

Days after the cyclone passed,

Airlie Beach was still without power and running water.

The continued bad weather frustrated aid efforts,

with roads blocked

and communications infrastructure damaged.

This happened so fast,

within six hours.

Had virtually no warning.

In fact, the warning I got was after the event.

The Logan river burst its banks,

and the area suffered from particularly extensive floods.

A lot of people have lost houses.

In this part of the Logan River,

there's people who have yet to discover

that they've lost their houses

because they stayed with family and friends.

They'll come back today and find that their house is underwater.

Homes were flooded, soaking belongings beyond repair.

In addition to homes and buildings being damaged,

farmland was also affected,

with many crops destroyed.

All told, Tropical Cyclone Debbie caused

insured losses of 1.7 billion Australian dollars.

The task of rebuilding was a daunting prospect,

set to impact people's lives for years to come.

As well as a physical toll,

such disasters can have a negative impact

on people's mental health.

Populations can bounce back and recover

from individual incidents.

However, Australia remains at risk of future cyclones.

Any rebuilding efforts need to consider

that they will be enveloped by the next inevitable cyclone.

Cyclones can't be avoided.

But the more we know about them,

the more it becomes possible to detect patterns

and learn to manage the risk.

If we are able to predict cyclones

and provide early warnings,

this information has the potential

to save thousands of lives each year worldwide.

Tropical cyclones by their nature

are difficult to predict.

They can change direction and dissipate at any time.

This makes long-term predictions difficult to make.

When it comes to weather warnings,

it is also important to avoid false positives.

Mobilizing rescue crews and evacuating populations

is costly and should only be done

when strictly necessary.

In some circumstances, the storm may abate

and it may become safer for populations to ride it out

rather than evacuate.

Fortunately, cyclones move quite slowly,

typically 16 to 32 kilometers per hour.

This allows some time for evacuation

and fortification of buildings against the storm.

Satellite imaging is key

in the early detection of a cyclone

because they normally form away from land.

Radar and computer modeling technologies

are being continuously developed.

Further research has involved flying planes

directly into cyclones to gather dimensional data

of the forces involved in the storm.

At ground level, so-called storm chasers

use customized vehicles built to collect data

as they follow the path of the storm.

International cooperation is key,

and countries work together to track cyclones

and share information.

These activities are coordinated at a global level

by the World Weather Watch program.

The point of gathering this data

is to shrink the cone of uncertainty

and ensure that predictions are accurate enough

to allow people to make the right decision

whether to evacuate or shelter during the next storm.

Cyclone Debbie was highly damaging

to the settlements on the Whitsunday Islands.

Coastal mangroves.

A tangle of trees adapted to survive

in the saltwater deltas.

A twisted knot of roots intertwined

forms an almost impenetrable barrier.

Mangroves' complex root systems

are evolved to withstand the action of the waves.

They form a natural defensive barrier,

protecting the landscape

from the extremes of cyclone activity.

In many parts of the world,

humans have cleared large areas of mangrove forest.

Previously known as Burma,

Myanmar is a country in South Asia

bordered by Bangladesh, India, China, Laos and Thailand.

In the last decade, Myanmar has lost

most of its mangrove forests along the coast

to shrimp farms and rice paddies.

The mangroves, not only do their root systems

hold the soil together

underneath the water or near the water,

but the trees themselves also protect against wave action.

And all of this helps prevent erosion of land

and it helps create new areas of land out from the coast.

And so mangrove forests help form a barrier

that protects further inland

from heavy waves and storm surge.

The data backs this up.

Studies have shown that mangroves

reduce the number of deaths in cyclone-hit areas.

In Myanmar, the destruction of the mangroves

has economic benefits in the short term.

The farms established in their place

are relied upon by the local populations

as a key element of their diet.

However, in the longer term,

the increased flood risk due to the loss of the mangroves

has the potential to impact the economy more.

Low-lying aquaculture ponds

and rice paddies present an inherent flood risk.

The ground is already waterlogged,

and any potential barriers

to the influx of water are removed.

In the event of storm surges, there is nothing to prevent

oceanic saltwater flowing inland, poisoning the crops.

With its tropical location,

Myanmar has a high risk of cyclone activity.

However, with its defenses depleted

in recent years, the risk of catastrophic floods

have continued to increase.

It was just a matter of time.

In 2008, time ran out.

2008 was the year

of the most deadly natural disaster

ever recorded in Myanmar.

It was caused by a tropical cyclone.

A tropical system was detected

in the Bay of Bengal

by Indian meteorologists on April the 27th.

By the following day, it had developed

into a Category 1 cyclone and was given the name Nargis.

Nargis was a tropical cyclone

that formed in the Bay of Bengal in late April, 2008.

And the Bay of Bengal has

among the highest sea surface temperatures

in the entire world,

especially between spring, summer and fall

in the Northern Hemisphere.

By May the 2nd,

Nargis had developed

into a deadly Category 4 cyclone,

and it made landfall near the town of Wagon

in the Ayeyarwady Division.

In Myanmar in particular,

the Cyclone Nargis was an event that--

None of which on that scale has happened before.

So the government was very much unprepared for that.

And people on the ground in the delta, of course,

were very vulnerable.

Typically, when a storm would hit

big, solid land of mountains, it would lose energy.

But in this case, in the delta,

the land is already completely flooded.

There's lots of warm water there.

It's very, very flat, there is no shelter.

And there's nothing to make the storm lose energy.

So as Nargis hit the river delta in Myanmar,

it didn't lose any energy at all.

The winds were incredibly intense

and the storm surge drove the water far inland from the delta

because the land was already flooded full of water.

That was what was responsible for the loss of life.

Nargis would go on to cause untold devastation,

destroying 450,000 homes and damaging a further 350,000.

Approximately 600 hectares of farmland were destroyed

and over 800,000 people were displaced.

Nargis could be considered a perfect storm of destruction.

However, there were several human factors to consider

that greatly increased the toll caused by the cyclone.

The country of Myanmar was not well prepared for cyclones.

It had no early warning system for incoming storms.

In the case of Cyclone Nargis,

it was only tipped off to the storm's presence

by Indian meteorologists.

It had no storm shelters or evacuation plans.

Much of its housing was particularly vulnerable,

built mainly from poor materials

in a haphazard fashion

without controls or building regulations.

Poor quality housing

is one of the main risk factors

in the developing world when facing extreme weather events.

Myanmar is one of the least developed countries

in the world and in Southeast Asia.

It's also one of the largest countries

in Southeast Asia actually, space-wise,

and it has about 55 million inhabitants who suffered under

authoritarianism, military rule, ethnic conflicts, civil war

ever since the independence of the country.

When the weather warnings did come,

many people doubted their accuracy

and didn't evacuate or prepare.

Previous forecasts in Myanmar had been so inaccurate,

people didn't believe these warnings...

the cone of uncertainty regarding storm predictions

having a deadly effect in this case.

Within a couple of days of landfall,

some 260,000 people were evacuated to temporary camps

throughout the Ayeyarwady River Delta.

Heavy rains and a 3.6-meter-high storm surge

destroyed up to 95 percent of the buildings

in the cyclone's path.

The floodwaters penetrated 48 kilometers inland

from the coast...

damaging not just homes,

but farms, fisheries, industry, roads and infrastructure.

The political situation at the time in Myanmar

greatly complicated the emergency response.

Myanmar at the time was considered a pariah state

while under the rule of an oppressive military junta

from 1962 to 2011.

The military were in place by force

rather than a democratic mandate.

Its response to the cyclone

greatly increased the human cost of the disaster.

During the disaster, despite international condemnation

by multiple world leaders,

including U.S. President George W. Bush

and British Prime Minister Gordon Brown,

Myanmar's rulers heavily resisted international aid

for too long.

We now estimate that 2 million people

faced famine or disease as a result

of the lack of cooperation of the Burmese authorities.

This is completely unacceptable.

There must be unfettered access to humanitarian agencies.

We've already made available 5 million pounds.

We've got a humanitarian team now in Rangoon

to assess all options

for getting help through to people in need.

You do have people that are dying every day.

And we don't have a sense at this point

that the response to date is adequate

to keep more people from dying.

It means, you know, probability of outbreaks,

disease outbreaks.

More people dying because of exposure,

because of disease, because of malnutrition,

because of hunger.

When aid finally came,

it was too late for many.

An official death toll doesn't exist.

Myanmar's military leaders didn't coordinate a count.

However, the confirmed death toll is known to be

at least 146,000.

At least 2.4 million people

were greatly impacted by Cyclone Nargis.

All told, it is estimated

that Cyclone Nargis caused

over 10 billion U.S. dollars' worth of damage,

making it the costliest cyclone to have occurred

in the North Indian Ocean basin.

Most of the discourse around cyclones

is focused on the damage they do

and the humanitarian challenges of dealing with the aftermath.

Climate change also needs to be factored in

when discussing the potential future outcomes

of extreme weather systems like cyclones.

Counterintuitively,

studies show cyclones are happening less often.

The number of tropical cyclones over the last 70 years

have steadily reduced.

Unfortunately, it's not all good news.

The cyclones that do occur

are more intense and more dangerous.

As the Earth warms,

the moisture content in the air increases,

which in turn feeds more powerful storms.

Computer models predict that for a two-degree Celsius rise

in global temperatures,

rainfall during a cyclone would increase 10 to 15 percent

and the storm's intensities would rise by

as much as 10 percent.

Rising sea levels increase the height of coastal storm surges

and greater flooding is likely.

The effects of climate change are already visible

in the cyclones that are affecting many countries.

The trend of more and more powerful storms

can be seen in Cyclone Idai,

which decimated parts of Southern Africa in 2019.

The impact a storm has on the population

depends not just upon the deadly ferocity

of the storm itself

but how well equipped a population is to deal with it.

In developing countries,

buildings are typically less robust

and less able to withstand the forces

of 160-plus kilometer-per-hour winds.

Emergency response services are underfunded,

and their ability to help is exacerbated

by poor transport infrastructure.

Food and medical supplies are often overstretched

by the sheer numbers of people involved.

This magnifies the human impact,

resulting in tens of thousands of casualties,

compared to the hundreds in the West

for a similar-size cyclone.

Cyclone Idai hit Southeastern Africa in March, 2019,

and went on to become

one of the hemisphere's most devastating storms.

Mozambique typically only gets

one significant storm every 10 years.

Because of this intermittent risk,

preparation for cyclones isn't prioritized.

It's unlikely, if an area

is very infrequently attacked by tropical cyclones,

that they will have the infrastructure in place

to move people, to have safe places

where they can evacuate people to.

So a storm that hits in an area

which is, shall we say, unprepared,

of course, like any event, is going to be more badly affected.

Between the 9th and the 12th of March, 2019,

a tropical storm strengthened into Tropical Cyclone Idai.

At its peak, sustained wind speeds

were around 177 kilometers per hour.

Idai's intensity receded over the next day or so.

But that trend didn't continue,

and Cyclone Idai's wind speed ramped up again.

By March the 14th, the sustained wind speeds

peaked at 193 kilometers per hour.

Cyclone Idai had a looping path

that made it unpredictable and difficult to track.

It actually made landfall twice in Mozambique.

On the 15th of March,

Idai made landfall in the Mozambican city of Beira.

It was not prepared for such a catastrophic storm.

The city of Beira was torn up

as the storm ripped through the buildings.

Many people were injured by the airborne debris.

Beira has about 500,000 people,

some of whom live right near the river in low-lying areas.

So because the system was able to push a surge of seawater

up the river in a populated region,

it made this system quite deadly at landfall.

And furthermore, it spent more days after that

with heavy rainfall, causing further river flooding

and other kinds of inland flooding.

Up to 90 percent of the buildings in Beira

were totally destroyed.

From Beira, Cyclone Idai continued inland,

leaving a trail of destruction in its wake

and reaching Zimbabwe on March the 16th.

Eventually, Idai killed at least 1300 people

and impacted over 3 million people across Madagascar,

Mozambique, Malawi and Zimbabwe,

making it the second deadliest cyclone

to hit the Southern Hemisphere.

Idai brought torrential rainfall,

causing catastrophic flooding in many areas,

displacing hundreds of thousands of people.

The floods helped spread infectious diseases,

including cholera and malaria.

Over 100,000 homes were destroyed

and at least 1 million acres of crops were ruined...

exacerbating food shortages

and placing the country at risk of famine.

Very intense rain

has hit the whole province,

which is swelling the river basins

and is putting additional populations

along those rivers at risk,

including the population

in certain cities such as Pemba.

We estimate that probably over 100,000 more people

are at risk of the flood.

The impact of storms such as Idai can last a long time.

People can suffer from disease and malnutrition

for many months after the storm has passed.

In some areas,

girls are caught between impossible choices for survival

as severe food shortages bite.

A rise of prostitution, sex for food,

forced and arranged marriages were noted

in the aftermath of the cyclone.

So the main impact of Storm Idai in Mozambique was the flooding.

The winds, of course, were very severe,

but the winds were relatively short-lived.

Idai was not a particularly severe windstorm

by any standard,

but it did produce vast amounts of rain,

a lot of storm surge,

and it deposited a large amount of water

on land that was already quite low-lying and wet.

As the floodwaters started to recede

and the slow, painful process of rebuilding began,

the unthinkable happened.

Less than six weeks after Cyclone Idai

tore through the country,

Cyclone Kenneth made landfall in Mozambique

on the 24th of April...

the second major storm to hit

in less than a two-month period.

Kenneth made landfall just north of Pemba in Mozambique.

Idai was bad.

Kenneth was worse.

When Kenneth came along not very long after Idai,

it was falling-- It was causing rain to fall

on an area that was already flooded.

People's homes were already devastated.

People were already living outside

because of the previous storm.

So that when the second storm came along,

they were totally exposed.

And the impact, of course, was amplified many times.

Kenneth was to become the most intense tropical cyclone

in Mozambique's recorded history,

with sustained winds of 225 kilometers per hour.

Scientists believe climate change may have had a hand

in triggering two storms so close together.

In the case of Idai when it hit Mozambique,

of course the flooding and the winds

caused a lot of people to be moved away from their homes.

A lot of people lost their homes and then were displaced.

They were battered by the first storm.

There was a lot of sickness, a lot of injury,

a lot of people didn't have water and food.

So under those conditions,

while people are camping essentially in the open air

in a very weakened state,

the arrival of the second storm, Kenneth,

a very short period afterwards was utterly devastating.

The two storms greatly impacted agriculture

in an area with 780,000 hectares of crops,

plunging some 200,000 children

into crisis levels of food insecurity.

Mozambique was hit by two cyclones

in March and April of 2019,

and that additional flooding

made more regions difficult to get to.

Roads were washed out.

This flooding was lasting for weeks on end.

And for those reasons, it was difficult

for international aid workers to reach

some of the villages and cities and towns

that had been affected.

And in addition, these regions are fairly poor,

and they are exposed to diseases

like cholera and malaria on a regular basis.

But these flooding conditions made those worse.

So, for instance, Mozambique had a cholera outbreak after Idai,

and Kenneth would have made that even worse.

Cyclones Idai and Kenneth happening so close together

was a once-in-a-generation disaster.

Populations still reeling from Idai

were in no position to deal with Kenneth.

An estimated 2.5 million people,

almost 10 percent of the country's population,

needed life-saving assistance.

Cyclones represent nature at its most primal,

a force we can't control or easily predict,

with winds and waves that are so powerful

that our defenses seem futile.

They can strike in many places

and often hit countries

not equipped to deal with them.

The initial landfall is frightening and chaotic,

but the really deadly disaster occurs in the aftermath

with the spread of disease and famine.

A country's infrastructure can be torn up,

hampering rescue efforts.

Even if people can escape

the initial danger of the storm,

where do they go?

Cyclones oust hundreds of thousands of people each year.

Where are these displaced populations housed?

The various dangers to these people remain

long after the storm has abated.

Some of the world's worst humanitarian disasters

have been triggered by cyclones,

with individual storms that negatively impact

millions of people while costing billions of dollars.

The relationship between climate change and cyclones

is still being tested,

but the trend is for more dramatic storms.

Unity among organizations is the lifeline to survival

in any disaster, let alone when faced

with the eye of Mother Nature's fury,

the catastrophic impact of cyclones.