Tropical Storms

This section explains Tropical Storms. Tropical storms are complex and powerful weather systems that can cause significant destruction. Their development is driven by warm ocean waters, and their impacts can be devastating for coastal communities. Climate change is expected to influence the frequency and intensity of these storms, making effective forecasting and preparedness more important than ever. While advances in technology have improved our ability to predict and track tropical storms, their unpredictable nature means that authorities and communities must remain vigilant and proactive in managing the risks they pose.

What is a Tropical Storm?

A tropical storm is a powerful weather system that forms over warm ocean waters, typically in tropical and subtropical regions. It is characterised by very strong winds, often exceeding 120 km/h, and heavy rainfall, which can reach up to 250 mm in just one day. These storms are highly dynamic and can cause significant damage due to their intensity and unpredictability. Tropical storms are known by different names depending on their location around the world. For instance, in the Caribbean and the United States, they are referred to as hurricanes; in South Asia, they are called cyclones; in East Asia, they are known as typhoons; and in Australia, they are called willy-willies. Despite their regional names, they all share similar features, development processes, and potential impacts.

Structure, Features, and Development of Tropical Storms

Tropical storms have a distinct structure, which can be broken down into key components:

1. The Eye: The centre of the storm is called the "eye." This is a calm, cloud-free region where winds are light, and the weather is clear. The eye is typically 20-40 miles (30-65 km) wide, and its calmness contrasts sharply with the chaos surrounding it.
2. The Eye Wall: Surrounding the eye is the "eye wall," which is the most dangerous part of the storm. It consists of towering clouds and intense winds, often exceeding 180 km/h. This area is where the strongest winds and heaviest rainfall occur.
3. Rainbands: These are spiral-shaped bands of clouds and heavy rain that extend outward from the eye. They are responsible for the heavy rainfall and strong winds in areas outside the immediate eye wall.

Tropical storms develop over warm ocean waters, usually between 5° and 20° latitude, where sea temperatures exceed 26°C. Warm, moist air rises from the ocean surface, creating a low-pressure area. As the air rises, it cools and condenses, forming clouds and releasing latent heat, which powers the storm. The rotation of the Earth causes the storm to spin due to the Coriolis effect, which gives tropical storms their characteristic spiral shape.

As the storm intensifies, it draws more energy from the warm ocean waters, and its wind speeds increase. Once the winds reach speeds of over 120 km/h, the system is classified as a tropical storm. If the winds exceed 150 km/h, the storm is classified as a hurricane, cyclone, or typhoon, depending on its location. These storms can last for days or even weeks, moving across the ocean and occasionally making landfall, causing destruction and loss of life.

The Impacts of Climate Change on Tropical Storms

Climate change is affecting the frequency, intensity, and nature of tropical storms. As global temperatures rise, the surface temperature of the oceans also increases, providing more energy for tropical storms to develop and intensify. This means that storms may become stronger, with higher wind speeds and more intense rainfall, leading to greater potential for flooding and damage.

Rising sea levels, another consequence of climate change, can also exacerbate the impacts of tropical storms, particularly storm surges (the abnormal rise in sea level caused by a storm). Higher sea levels allow storm surges to travel further inland, increasing the risk of coastal flooding.

Furthermore, climate change is causing shifts in atmospheric conditions, which may alter the patterns of storm formation and movement. Some regions that previously did not experience tropical storms may begin to see them more frequently, while others may experience a decrease in storm activity. This unpredictability poses challenges for communities and authorities trying to plan for and manage the risks associated with tropical storms.

Predicting Tropical Storms - Forecasting Centres

The ability to predict tropical storms has improved significantly in recent decades, thanks to advances in technology and improved meteorological understanding. Various forecasting centres around the world use sophisticated tools to track and predict the movement, intensity, and potential impacts of tropical storms. These tools include:

• Satellites: Satellites provide valuable data on sea surface temperatures, cloud cover, and storm development. This helps meteorologists monitor the formation of storms and track their progress over the ocean.
• Weather Radars: Radars help to detect precipitation, wind speed, and storm rotation, providing real-time data on the storm’s intensity and direction.
• Computer Modelling: Advanced computer models simulate the movement of storms and predict their future paths based on current conditions. These models take into account various factors, such as wind patterns, sea surface temperatures, and atmospheric pressure, to forecast the storm’s trajectory and potential impacts.

Forecasting centres, such as the National Hurricane Center (NHC) in the United States, the Indian Meteorological Department (IMD) in South Asia, and the Japan Meteorological Agency (JMA) in East Asia, play a critical role in providing early warnings and guidance to governments and communities. These warnings help authorities to prepare for the arrival of storms, allowing for the evacuation of vulnerable areas, the securing of infrastructure, and the distribution of emergency supplies.

Despite these advances in forecasting, tropical storms remain unpredictable, and there is still a margin of error in the timing and severity of storms. This highlights the importance of preparedness and ongoing research into improving storm prediction and mitigation strategies.