Changing Coastal Environments » Cyclone, Hurricane and Typhoon Impacts

What you'll learn this session

Study time: 30 minutes

The difference between cyclones, hurricanes and typhoons
How these tropical storms form and develop
Primary and secondary impacts on coastal environments
Short and long-term responses to tropical storms
Case studies of major tropical storms and their effects
How climate change may affect future tropical storm patterns

Understanding Tropical Storms

Tropical storms are powerful weather systems that form over warm ocean waters and can cause devastating impacts when they reach coastal areas. Though they have different names in different parts of the world, they're essentially the same weather phenomenon.

Key Definitions:

Tropical Cyclone: The general term for a low-pressure system that forms over tropical waters with organised thunderstorm activity and circulating winds.
Hurricane: A tropical cyclone that forms in the Atlantic Ocean or Northeast Pacific with sustained winds of at least 74 mph (119 km/h).
Typhoon: A tropical cyclone that develops in the Northwest Pacific Ocean.
Storm Surge: An abnormal rise in sea level during a storm, measured as the height of the water above the normal predicted tide.

🌀 Where Tropical Storms Form

Tropical storms form over warm ocean waters (at least 27°C) between approximately 5° and 30° latitude north and south of the equator. They need:

Warm sea surface temperatures
High humidity in the lower atmosphere
Light winds in the upper atmosphere
A trigger mechanism (often a pre-existing weather disturbance)

💨 Measuring Tropical Storms

Tropical storms are classified by their wind speeds:

Saffir-Simpson Scale (Hurricanes): Categories 1-5
Category 1: 74-95 mph - Some damage
Category 3: 111-129 mph - Devastating damage
Category 5: 157+ mph - Catastrophic damage

How Tropical Storms Form and Develop

Understanding the life cycle of a tropical storm helps explain why they can be so destructive when they reach coastal areas.

1️⃣ Formation

Warm ocean water evaporates and rises, creating an area of low pressure. Air rushes in to fill this low pressure and begins to spiral due to the Coriolis effect.

2️⃣ Development

As more warm, moist air is drawn in, it releases heat as it condenses into clouds. This heat energises the storm, causing wind speeds to increase and pressure to drop further.

3️⃣ Dissipation

Storms weaken when they move over cooler water or land, as they lose their energy source (warm water). The friction from land also slows wind speeds.

Impacts on Coastal Environments

Tropical storms can have devastating effects on coastal areas, with both immediate and long-term consequences.

⚡ Primary Impacts

Storm surges: Cause coastal flooding, often the deadliest aspect
High winds: Damage buildings, infrastructure and vegetation
Heavy rainfall: Leads to flooding and landslides
Large waves: Erode beaches and coastal defences
Coastal erosion: Can permanently alter coastlines

🔄 Secondary Impacts

Water contamination: From sewage and chemicals
Disease outbreaks: Due to poor sanitation
Power outages: Affecting hospitals and emergency services
Economic losses: Tourism, fishing and agriculture
Ecosystem damage: Coral reefs, mangroves and coastal habitats

Responses to Tropical Storms

Responses to tropical storms can be divided into immediate and long-term measures, as well as preparation strategies.

🚨 Immediate Responses

Emergency evacuations
Search and rescue operations
Provision of emergency shelter, food and water
Medical assistance for the injured
Restoring essential services (electricity, water)

🏗️ Long-term Responses

Rebuilding homes and infrastructure
Improving coastal defences
Implementing stricter building codes
Developing better early warning systems
Creating disaster management plans
Restoring damaged ecosystems

Preparation and Mitigation

Countries prone to tropical storms have developed various strategies to reduce their impacts:

Early warning systems: Satellite monitoring and weather forecasting
Education: Teaching communities about evacuation procedures
Building regulations: Hurricane-resistant construction techniques
Natural buffers: Preserving mangroves and coral reefs
Flood defences: Sea walls, flood gates and storm surge barriers

Case Study: Hurricane Katrina (2005)

Location: Gulf Coast of the United States, particularly New Orleans

Strength: Category 5 at peak, Category 3 at landfall

Impacts:

Over 1,800 deaths
$125 billion in damage
80% of New Orleans flooded when levees failed
1 million people displaced
Severe damage to coastal wetlands and barrier islands

Responses:

Widely criticised emergency response
$14.5 billion spent on improving New Orleans' flood defences
Redesigned evacuation plans
Coastal restoration projects
Changes to building codes in vulnerable areas

Case Study: Typhoon Haiyan (2013)

Location: Philippines (particularly Tacloban City)

Strength: Category 5 super typhoon with winds up to 315 km/h

Impacts:

Over 6,300 deaths
4 million people displaced
Storm surge up to 5 metres high
90% of buildings in Tacloban destroyed
Severe damage to rice crops and fishing industry

Responses:

International aid of over $800 million
"Build Back Better" programme
Improved early warning systems
Relocation of communities away from high-risk coastal areas
Mangrove restoration projects to act as natural buffers

Climate Change and Tropical Storms

Scientists are studying how climate change might affect tropical storms in the future:

Frequency: The total number of storms may not increase, but...
Intensity: More Category 4 and 5 storms are likely as ocean temperatures rise
Rainfall: Warmer air holds more moisture, leading to heavier rainfall
Storm surge: Rising sea levels will make storm surges more damaging
Range: Storms may form in new areas as ocean temperatures change

Protecting Coastal Environments

Sustainable approaches to managing the impact of tropical storms include:

🌳 Ecosystem-Based Approaches

Natural solutions that work with coastal ecosystems:

Mangrove restoration and protection
Coral reef conservation
Beach and dune restoration
Creating wetland buffer zones

🏙️ Community Resilience

Helping communities adapt to storm risks:

Improved building standards
Land-use planning to avoid high-risk areas
Community-based early warning systems
Education and preparedness training

Summary

Tropical storms (cyclones, hurricanes and typhoons) are powerful weather systems that can have devastating impacts on coastal environments. They form over warm ocean waters and are driven by heat energy released when water vapour condenses. Their impacts include storm surges, high winds, heavy rainfall and coastal erosion, leading to both immediate destruction and long-term consequences.

Responses range from emergency relief to long-term rebuilding and mitigation strategies. As climate change continues, coastal communities may face more intense storms and higher storm surges due to rising sea levels. Sustainable approaches to managing these impacts include both engineered solutions and ecosystem-based approaches that work with natural coastal defences.

🧠 Test Your Knowledge!