explain why floods risk is high in and after a tropical cyclone
Flooding risk is high during and after a tropical cyclone due to several factors:
1. Heavy Rainfall: Tropical cyclones are known to bring intense and prolonged periods of rainfall. These storms have large atmospheric moisture content and can release huge amounts of water in a short span of time. The combination of rainfall and high winds can lead to extensive flooding.
2. Storm Surge: During a tropical cyclone, strong winds generate a phenomenon called a storm surge. It is a rise in sea level that occurs beneath the cyclone due to low atmospheric pressure and strong onshore winds. Storm surges can push large volumes of water onto coastal areas, resulting in extensive flooding along shorelines and low-lying regions.
3. Landfall Impact: When a tropical cyclone makes landfall, it can cause significant damage to infrastructure, such as dams, levees, and drainage systems. This damage further exacerbates the flooding risk. If the cyclone passes over a region with poor drainage or inadequate flood control measures, it increases the chances of widespread flooding.
4. Saturation of Soil: Prior to a tropical cyclone, the soil may already be saturated due to preceding rainfall events or high groundwater levels. The additional intense rainfall during the cyclone can exceed the soil's capacity to absorb water, leading to rapid runoff and flooding.
5. Topography: The topography of an area can also influence the flood risk during and after a tropical cyclone. Regions with flat terrain or low-lying coastal areas are more prone to flooding as water accumulates easily in such areas.
6. Slow Movement: Some tropical cyclones may move at a slow pace or stall over a particular region. This prolonged exposure to heavy rainfall increases the likelihood of flooding as water has more time to accumulate and saturate the ground.
7. Flash Flooding: Intense rainfall associated with tropical cyclones can cause flash flooding. Flash floods occur when water rapidly accumulates in low-lying areas, such as river valleys, causing a sudden and violent surge of water. These floods can be particularly dangerous as they occur with little warning and can lead to significant loss of life and property.
In summary, the high flood risk during and after a tropical cyclone is due to heavy rainfall, storm surges, landfall impact, soil saturation, topography, slow movement, and the potential for flash flooding. All these factors combine to create the ideal conditions for flooding, making it a significant hazard associated with tropical cyclones.