Weather and Extreme Storms

Weather is something we experience every single day — sunshine, rain, wind, clouds, snow. But have you ever wondered what actually causes it? Why does it rain on some days and not others? Why is it hot in summer and cold in winter? And what makes a calm, sunny day turn into a violent storm?

All weather is caused by the Sun heating the Earth's atmosphere unevenly. The Sun's rays hit the equator more directly than the poles, which means tropical regions get much more heat. This creates differences in temperature across the planet, and these temperature differences drive everything else — wind, rain, clouds, and storms.

Warm air rises because it is lighter than cold air. As warm air rises, it cools down, and the water vapour inside it turns into tiny droplets that form clouds. When those droplets become heavy enough, they fall as rain. This simple process — warm air rising, cooling, forming clouds, and producing rain — is the engine behind most of the world's weather.

Wind is caused by air moving from areas of high pressure to areas of low pressure. When the Sun heats the ground, the air above it warms up and rises, creating an area of low pressure. Cooler air from surrounding areas rushes in to fill the gap — and this movement of air is what we feel as wind. The bigger the difference in pressure between two areas, the stronger the wind.

Most weather is gentle and predictable. But sometimes, when the right conditions come together, the atmosphere produces something far more dramatic — extreme weather events that can be among the most powerful and destructive forces on Earth.

Tornadoes and hurricanes are two of the most powerful and terrifying weather events on Earth. Although they are both violent spinning storms, they are actually very different in how they form, how big they are, and how long they last.

A tornado is a rapidly spinning column of air that stretches from a thunderstorm cloud down to the ground. Tornadoes are usually between 100 and 500 metres wide, and most last less than ten minutes. But in that short time, they can be incredibly destructive. The strongest tornadoes produce winds of more than 480 kilometres per hour — fast enough to pick up cars, tear roofs off buildings, and throw heavy objects hundreds of metres through the air. The United States experiences more tornadoes than any other country — about 1,200 every year, mostly in an area called "Tornado Alley" in the central United States.

Hurricanes are much larger and last much longer than tornadoes. A hurricane is a massive rotating storm system that forms over warm ocean water. Hurricanes can be hundreds of kilometres wide and can last for days or even weeks. They produce powerful winds, enormous waves, and torrential rain that can cause devastating flooding. Hurricane Katrina, which hit the United States in 2005, killed more than 1,800 people and caused over 125 billion dollars in damage.

In different parts of the world, hurricanes have different names. In the western Pacific, they are called typhoons. In the Indian Ocean, they are called cyclones. Thailand occasionally experiences the effects of typhoons and tropical storms, particularly in the south of the country during the monsoon season.

Lightning is one of nature's most spectacular and dangerous phenomena. A single bolt of lightning can reach temperatures of 30,000 degrees Celsius — that is five times hotter than the surface of the Sun. Lightning strikes the Earth about 100 times every second — that is more than 8 million strikes per day.

Lightning happens when electrical charge builds up inside storm clouds. The top of the cloud becomes positively charged and the bottom becomes negatively charged. When the difference in charge becomes large enough, a massive spark of electricity jumps between the cloud and the ground — or between two clouds. This spark is the lightning bolt. The heat from the lightning causes the air around it to expand so rapidly that it creates a shockwave — and that shockwave is what we hear as thunder.

You can estimate how far away lightning is by counting the seconds between seeing the flash and hearing the thunder. Sound travels about one kilometre every three seconds, so if you count nine seconds between the flash and the thunder, the lightning is about three kilometres away.

Floods are the most common and most deadly type of natural disaster in the world. They happen when water covers land that is normally dry — usually because of heavy rain, overflowing rivers, or storm surges along the coast. Flash floods are particularly dangerous because they happen very quickly, giving people little time to escape. In Thailand, flooding is a serious annual concern, particularly during the rainy season from May to October. The devastating floods of 2011, which affected more than 13 million people across Thailand, demonstrated how vulnerable even modern cities can be to extreme rainfall.

Scientists around the world agree that extreme weather events are becoming more frequent and more severe. The reason is climate change — as the planet warms due to greenhouse gas emissions, the atmosphere holds more energy, and that extra energy makes weather more extreme.

Warmer air can hold more water vapour, which means heavier rainfall and more intense flooding. Warmer oceans provide more energy to hurricanes, making them stronger and more destructive. Heat waves are lasting longer and reaching higher temperatures. Droughts are becoming more severe in some regions, while other regions are experiencing record-breaking rainfall.

The numbers tell a clear story. According to the World Meteorological Organization, the number of weather-related disasters has increased by five times over the past 50 years. While better warning systems mean fewer people die in each event, the economic damage from extreme weather has increased dramatically — costing the world hundreds of billions of dollars every year.

So what can be done? Scientists say the most important thing is to reduce greenhouse gas emissions by switching from fossil fuels to clean energy sources like solar, wind, and hydroelectric power. But even if we stopped all emissions today, the warming already in the system means extreme weather will continue to worsen for decades. This means communities also need to adapt — building stronger buildings, improving flood defences, developing better warning systems, and planning cities that can cope with the weather of the future, not just the weather of the past.

Understanding extreme weather is no longer just interesting science — it is essential knowledge for everyone living on a warming planet.