Cyclone Fengal made landfall over Puducherry on Saturday (November 30) evening. As a precaution, the Tamil Nadu government moved around 471 people to six relief centres in Tiruvallur and Nagapattinam districts. Boats, generators, motor pumps and necessary equipment were readied and the National Disaster Response Force (NDRF), and state rescue teams were deployed in vulnerable areas. What is the ‘landfall’ of a cyclone? Simply put, landfall is the event of a tropical cyclone coming onto land after being over water. As per the India Meteorological Department (IMD), a tropical cyclone is said to have made landfall when the centre of the storm – or its eye – moves over the coast. Crucially a landfall should not be confused with a ‘direct hit’, which refers to a situation where the core of high winds (or eyewall) comes ashore but the centre of the storm may remain offshore. As per the US National Oceanic and Atmospheric Administration (NOAA), because the strongest winds in a tropical cyclone are not located precisely at the centre, it is possible for a cyclone's strongest winds to be experienced over land even if landfall does not occur. What is the damage caused by a cyclone’s landfall? The damage caused by the landfall will depend on the severity of the cyclone – marked by the speed of its winds. If the cyclonic storm is “very severe”, the impact may include extensive damage to kutcha houses, partial disruption of power and communication lines, minor disruption of rail and road traffic, potential threat from flying debris and flooding of escape routes. The factors behind this kind of damage include extremely strong winds, heavy rainfall and storm surges which cause devastating floods on the coast. How long does a landfall last? Landfalls can last for a few hours, with their exact duration depending on the speed of the winds and the size of the storm system. Cyclones lose their intensity once they move over land because of a sharp reduction of moisture supply and an increase in surface friction. This means that while landfalls are often the most devastating moments of cyclones, they also mark the beginning of its end.
