👉 🔥 CLICK HERE! 🔥 👈

In Australia, flooding is the second deadliest natural disaster after heatwaves. So what causes a flood and how do you know its coming? A flood is an overflow of water that exceeds the normal boundaries of a watercourse. Floods occur when water overflows over normally dry land. This can happen when water flows from a natural watercourse such as a lake, river or stream. It can also happen when water is released from a reservoir, canal or dam. There are two types of floods: river floods and flash floods. River flooding occurs when rivers overflow their banks and flood the surrounding land. This is mainly due to heavy rains, but can also be caused by high tides, thunderstorms, snowmelt, and dam failures. In inland Queensland, New South Wales and Western Australia, river flooding can affect thousands of square kilometers in weeks or even months. Flash floods occur within six hours of rain. This can happen after a short period of heavy rain, such as a thunderstorm. Flash flooding can become a major problem in urban areas if drainage systems fail and tend to affect a specific area. The most common cause of rivers and flash floods are heavy rains. Rivers form over thousands of years. Each river is unique and shaped in response to: normal local rainfall and runoff, local topography, vegetation and soil types. These features remain relatively constant over time, only the amount of precipitation changes. Rivers have a maximum water content. More rainfall than usual results in more outflow than usual. This runoff cannot be carried by the riverbed, so it flows into the ground. If the time between rain and flood exceeds six hours, it is a river flood. River flooding may occur shortly after rain in some areas. River flooding often peaks on rainy days. However, due to the length of many rivers in Australia, flooding can occur weeks or months after rain.hundreds of kilometers away. For example, it can take months for floods in the upper Murray River, Australias longest river at more than 2,500 km, to reach its mouth in South Australia. King flood The term king flood is often used to describe an extremely high tide. These tides are a natural and predictable part of the tidal cycle. The season of their occurrence varies by location and year. They can have a very significant impact where the ocean meets the land at beaches, estuaries, harbors and other coastal areas. Kingdom tides can increase the impact and extent of river floods. Imagine a seaside town on a coastal river. If the river overflows, part of this town could be flooded. When a high tide occurs at the same time as a king tide, the tide is less likely to run out to sea. It is likely that most of this city will be flooded, and at an even higher level. Storm Surge A storm surge is an elevation above normal sea level on a coast caused by a storm. A storm often produces strong offshore winds and is usually caused by low barometric pressure. Storm surges are often accompanied by a tropical cyclone. Storm surges may occur outside the tropics due to an intense low pressure system. Coastal flooding is possible during storms. And when storm surge joins river flooding, the flood area and volume can increase. Melting Snow Snow can be thought of as a reservoir of water waiting for enough heat to flow downhill. When conditions warm up quickly, snow can melt quickly. When this happens, water can be released that is too much for the lower river channels, which can cause river flooding. Releasing Dams Dams can hold huge amounts of water, but all dams have capacity. When the dam reaches capacity, dam operators can release water, sometimes causing flooding. We work closely with dam operators during high tides to provide them with the latest weather information. Operators use this information to manage theirin such a way as to minimize the impact on downstream communities. People dont see floods as dangerous compared to raging fires or the howl of a tropical cyclone. However, flooding is a major threat as it is the second largest natural disaster in Australia (Haynes 2017). The danger is often underestimated, with catastrophic consequences. People died walking or moving in the flood waters. Unfortunately, most flood injuries and deaths are preventable. Most people are shocked to learn how dangerous it is to be caught in a flood. A small car weighing about 1 ton can only move through flood water 15 cm deep, flowing at a speed of 1 m per second. A small car floats completely to a depth of 60 cm. This is due to the buoyancy of the car due to sealed doors and inflated tires. Haynes, K. 2017, Analysis of building losses and loss of life due to natural disasters, published in Where, why and how do Australians die in floods?, Accessed 27 August 2020 27 August 2020 .

Items