Sunday, 5 May 2019

Cyclone Fani kills at least 28 in India and Bangladesh.

Cyclone Fani is reported to have caused 28 known fatalities in India and Bangladesh after making landfall in Odisha State, India, on Friday 3 May 2019. The majority of the deaths occurred in Odisha, where the storm was the largest to come ashore since the un-named storm of 1999, which killed over a thousand people, prompting India to initiate a program of mass-evacuations of low-lying coastal areas when large storms approach. On this occasion around 1.2 million people were evacuated from their homes in the 24 hours before the storm made landfall, though 16 people still lost their lives, with about 160 being injured, with the extensive storm damage reported in coastal areas, particularly around the town of Puri, close to where Fani made landfall, and in the state capital, Bhubaneswar. After hitting Odisha the storm veered to the northeast, making landfall in Bangladesh were 12 people were killed despite an evacuation of 1.6 million.

Storm damage in the town of Puri in Odisha, following the passage of Cyclone Fani. Dibyangshu Sarkar/AFP/Getty Images.

Tropical storms, called Cyclones in the Indian Ocean, are caused by solar energy heating the air above the oceans, which causes the air to rise leading to an inrush of air. If this happens over a large enough area the inrushing air will start to circulate, as the rotation of the Earth causes the winds closer to the equator to move eastwards compared to those further away (the Coriolis Effect). This leads to tropical storms rotating clockwise in the southern hemisphere and anticlockwise in the northern hemisphere.These storms tend to grow in strength as they move across the ocean and lose it as they pass over land (this is not completely true: many tropical storms peter out without reaching land due to wider atmospheric patterns), since the land tends to absorb solar energy while the sea reflects it.

 Damage to the railway station in Puri following the passage of Cyclone Fani. Partha Paul/Indian Express.

Despite the obvious danger of winds of this speed, which can physically blow people, and other large objects, away as well as damaging buildings and uprooting trees, the real danger from these storms comes from the flooding they bring. Each drop millibar drop in air-pressure leads to an approximate 1 cm rise in sea level, with big tropical storms capable of causing a storm surge of several meters. This is always accompanied by heavy rainfall, since warm air over the ocean leads to evaporation of sea water, which is then carried with the storm. These combined often lead to catastrophic flooding in areas hit by tropical storms.

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