We take a look at what cyclones are, why they’re dangerous, and how cities can prepare and recover from such events.
The weather is something that impacts all of our lives in some way. It controls how water is distributed across the planet, giving us freshwater and influencing our agriculture. Historically, the weather was an unpredictable force.
Yet since the earliest of civilisations, people have been trying to understand and forecast how it will behave. Despite getting better at these predictions, extreme weather events can cause chaos and devastation, even when we know it’s coming. And, with climate change, these events are becoming increasingly deadly. Cyclones in India are one such example of this shift, and we take a look at them in more detail.
What is a Cyclone?
A cyclone is essentially a large weather system that has particular characteristics. They’re formed around a strong centre of low atmospheric pressure, which causes winds to rotate inwards in a clockwise direction. This formation gives them the appearance of a coiled snake, which is where the name comes from.
On Earth, cyclones are some of the most devastating natural forces to human life. Yet we experience them every year, particularly in tropical areas. They’re not something unique to our planet, either. We’ve also spotted cyclones on Mars, Jupiter and Neptune.
What’s in a name?
If we think of cyclones as tropical storms, we may also think of things such as hurricanes and typhoons. So what’s the difference between the three? Essentially, they’re the same thing, but it’s where they’re formed that’s important:
- Cyclones form over the Indian and South Pacific Oceans
- Hurricanes form over the North Atlantic and Northeast Pacific
- Typhoons form over the Northwest Pacific
To make things slightly more confusing, there are also different types of cyclones. As well as tropical cyclones, there are also extratropical cyclones and tornadoes. Extratropical cyclones emerge when there are temperature contrasts and are low-pressure systems, and rotate in the opposite way to tropical cyclones. Tornadoes are columns of air that rotate rapidly downward from a thunderstorm.
You’ll often see that cyclones and other big storms are named. This helps us keep track of them, both in the media and from a scientific point of view. Usually, the first storm of the year is named beginning with A, the next one B, and so on. If a storm is particularly bad, the name won’t be reused in future.
If all of this weather talk is intriguing you, you might want to check out our course Learn About Weather. The Met Office, Royal Meteorological Society, and the University of Exeter worked to develop this fascinating look at all things weather.
Why are cyclones so destructive?
Along with very strong winds, cyclones bring heavy rain, storm surges (coastal floods), and tornadoes. This combination of extreme weather can bring devastation to areas. Some estimates suggest that around 10,000 people are killed on average each year as a result of these storms.
Coastal areas are particularly at risk from cyclones, especially those that are densely populated. The strong winds can damage buildings and infrastructure, while rain and storm surges can lead to flooding. Other risks include landslides, mudslides and coastal erosion.
It’s not just the event itself that’s damaging. The after-effects of cyclones can cause widespread chaos as people try and rebuild their lives. Standing water can lead to disease, electrical and water services can be interrupted, and the costs can spiral out of control.
These tropical storms have impacted humans and other animals throughout history. They’re some of the most deadly natural disasters we experience, and there is evidence to suggest they’re getting stronger and lasting longer.
A history of cyclones in India
India has a long and tragic history with cyclones. The Indian subcontinent is among the worst affected regions of the world when it comes to tropical storms. It’s particularly vulnerable due to its 4,670-mile coastline, where a large percentage of the country’s population lives.
Cyclones generally tend to form in the North India Ocean between April and November each year. Usually, there is a primary peak in November and a secondary peak in May. The storms can affect the entire coast of India. However, the east coast is more prone compared to the west.
Over the years, there have been some catastrophic cyclones that have hit the country. Here are some of the most notable cyclones in India throughout recent history:
The 1970 Bhola cyclone
The Bhola cyclone is one of the deadliest natural disasters ever recorded. The storm formed over the Bay of Bengal in November 1970 and made landfall on the coast of East Pakistan (now Bangladesh) before continuing on to West Bengal.
At its peak, the cyclone generated winds of up to 115 mph devastating the coastal regions it encountered. It’s estimated that between 300,000 and 500,000 people were killed during the disaster, making it the deadliest tropical cyclone on record.
The 1991 Bangladesh cyclone
Another deadly cyclone that formed over the Bay of Bengal was the 1991 Bangladesh cyclone. By the time it reached land in Bangladesh and eastern India, winds of up to 155 mph were recorded, making it one of the most powerful on record.
The cyclone caused a deadly storm surge that was 20ft high. It swept over the coastline, claiming the lives of at least 138,866 people. In the fallout of the storm, various countries carried out one of the largest military relief efforts on record, Operation Sea Angel.
The 1999 Odisha cyclone
This storm was the most intense tropical cyclone ever recorded in the North Indian Ocean. It was also one of the most destructive in the region. At the peak of the storm, winds of up to 160 mph were recorded, as well as a record-low pressure.
As well as hitting the state of Odisha in India, Thailand, Myanmar, and Bangladesh also all felt the impact. Nearly 10,000 people died, and it caused around $4.44 billion worth of damage.
Cyclones during the pandemic
As the world tries to tackle the coronavirus, the seasons and all they bring continue to impact us. This has been evident over the last couple of months, as cyclones have already started touching down on the coast of India.
Since the middle of May this year, we’ve seen Super Cyclonic Storm Amphan strike the Ganges Delta and, Severe Cyclonic Storm Nisarga hit the Indian state of Maharashtra. Both of these cyclones had severe effects on areas of the country.
This storm is one of the worst to hit the region since 2007, and the first ‘super’ storm since the 1999 Odisha cyclone (mentioned above). The storm killed at least 72 people in West Bengal and a further 12 in Bangladesh.
The storm reached land on May 20 near the city of Kolkata, leaving 14 million people without power and chaos in its wake. It’s estimated that cyclone Amphan caused over $13 billion of damage, as winds reached up to 160 mph.
On the opposite side of the country, cyclone Nisarga formed over the Arabian Sea at the beginning of June. As it began to gather strength, experts feared that the storm could strike the city of Mumbai. Typically, tropical cyclones form less frequently over the Arabian Sea and usually head west towards Oman.
At the time, Mumbai was the city in India that was worst hit by the coronavirus. In early June, there were over 40,000 confirmed cases. It’s also the most populous city in the country, home to more than 20 million people. Thankfully, the eye of the storm narrowly missed Mumbai.
Mumbai’s first June cyclone in 129 years – nearly
Cyclone Nisarga was a near miss for Mumbai, a city that’s vulnerable to natural disasters. A similar situation happened in November 2009 with Cyclone Phyan. The last time a deadly storm directly hit the city was back in 1948, but that wasn’t a full-blown cyclone. According to records dating back to 1891, no cyclones have ever made landfall near Mumbai during June.
Thankfully, humanitarian action is often on hand when the worst does occur. A quick response is crucial to saving lives. Agencies in India and internationally reacted to rescue people and deliver aid to those affected by the storm. However, it raises the question as to what we can expect from these extreme weather events in the future.
The future of extreme weather
The current examples of cyclones in India show just how catastrophic extreme weather can be. However, like many emergencies and disasters, as we investigate these events, there are trends that we can spot. This helps us to better prepare for when the worst does happen. In Mumbai, for example, over 100,000 people, including coronavirus patients, were moved to safety.
But the science of climate change is clear – human activity is increasing the risk of some types of extreme weather. According to some experts, ‘As the climate continues to warm, it is expected that extreme tropical cyclone precipitation events and resulting inland flooding will become yet more frequent.’
Even if climate change doesn’t directly result in more cyclones in India or elsewhere, it can intensify their effects. There is a mounting body of evidence linking several factors to this:
- Warmer sea temperatures. When it comes to hurricanes (tropical storms similar to cyclones), warmer temperatures in the sea could be significant. It could increase the speed of the winds by up to 10% and mean they have 10-15% more precipitation. Both of these factors could cause more flooding and widespread damage.
- Rise in sea level. Sea levels are expected to rise by 1-4 feet due to global warming. As a result, storm surges caused by cyclones and hurricanes could be even more damaging.
- Different areas. As temperatures shift across the globe, so could the patterns of tropical storms. This could mean that areas that don’t usually experience cyclones, such as Mumbai, could be more at risk. Many of these places currently won’t have the infrastructure to protect against these storms.
These tropical storms are just one of the implications of global warming. Therefore, it’s more important than ever that we understand the causes of climate change and how we can slow it. It’s clear that we’re nearly at a tipping point when it comes to the natural systems of the environment, and we must act quickly to avoid disaster.
How to prepare for a cyclone
With cyclones, hurricanes and typhoons all being yearly occurrences, we have got pretty good at preparing for them. From individual to global efforts, by studying and predicting cyclones, we’re able to save millions of lives.
One of the most crucial elements to preparing for cyclones in India and other countries is to have systems in place to deal with them. Emergency shelters are constructed, evacuation plans are made, and emergency response systems are developed.
A good example of this infrastructure can be found on our course on climate resilience. It explores how plans, designs, upgrades, and maintenance can keep roads in action. It’s efforts like these that are essential for making sure people can move safely during disasters.
We are getting far better at understanding and predicting weather patterns across the globe. By using satellite images, computer models, and other weather instruments, it’s possible to detect and track cyclones.
In our course on big data and the environment, you can explore some of the ways analytics are used to predict weather fluctuations. There are many different ways data can be used to help plan for extreme events and protect people during them.
The forces of nature are largely beyond our control. Although we can predict the path a cyclone may take, it’s impossible to know exactly. We also can’t stop tropical storms as they progress across sea and land. However, we can plan for ways to reduce the risk they pose.
Our Disaster Risk Reduction course looks at some of the ways of how risks can be minimised. It explores how disasters are managed, how practices have evolved, and why it’s important to reduce risks.
In India, there is a government-led project to manage cyclone risks. It hopes to reduce the impact of cyclones in a few ways. This includes improving early warning systems, helping communities to respond, and improving shelter and evacuation methods.
How to recover from a cyclone
Even with all the preparation that goes into reducing risk and predicting storm paths, cyclones can be incredibly destructive. Individuals, communities, and entire regions can be impacted by tropical storms. The high winds and flooding can damage and destroy property and road, while livelihoods can be ruined.
However, people and communities are often resilient. With the right support, they can rebuild their lives and support each other. As this course on community preparedness, recovery, and resilience explores, fostering positive developments is crucial. It also looks at disaster management and sustainable development.
Accountability is another essential part of disaster management. On a local and global scale, it’s essential for reducing the effects of events such as cyclones. Our course looks at the tools used in accountability and how they’re applied at different stages of recovery.
As for cyclones in India, work is already underway to pick up the pieces of Cyclone Amphan and Cyclone Nisarga. Police and disaster relief teams were on the scene to remove debris and repair communication lines. People also started to leave shelters and return to their homes in the days after the storm.
For many, there is a struggle ahead. Some areas are experiencing a lack of water and food, and some people have been left without a roof over their heads. Despite the government and charities sending aid, there is a long road to recovery ahead.
When it comes to extreme weather, tropical storms like cyclones can be devastating. Throughout history, we’ve seen catastrophic storms affect the lives of millions. When it comes to cyclones in India, they’ve had some of the worst ever recorded. Cyclone Amphan and Cyclone Nisarga are just two of the latest.
However, we have become better at predicting and monitoring these forces of nature. This allows countries, communities and people to prepare for the worst. And, whenever there is a disaster of this nature, people rally to rebuild what is lost.