Cyclones deconstructed - The New Indian Express

Cyclones deconstructed

Published: 19th November 2012 12:26 PM

Last Updated: 19th November 2012 12:26 PM

Some two weeks before one of the most contentious presidential elections in US history a depression in the Gulf of Mexico strengthened into a hurricane that swept a destructive swathe through the Caribbean states before targeting the eastern coast of the US. Whether its strength as it moved into the US was due partly to the heat and bile generated by the elections is not known. What is known is that Hurricane Sandy was the most destructive storm to hit the US, far surpassing Hurricane Katrina (2005) in its impact as it affected 24 of the 51 American states. Nearly 200 people were killed in five countries and tentative estimates of the damage have already crossed $50 billion.

Around the same time a small depression in the Bay of Bengal gathered enough force to be given a name, Nilam, as it moved towards the southern coast of India. The Category One storm was forecast to land somewhere near Chennai, and both officials and residents of Tamil Nadu and southern Andhra Pradesh waited nervously, dreading the impact and possible destruction. In the end, it was something of a non-event for Chennai. Nilam was small in the scale of cyclones and caused minimal damage in the state but it still took 21 lives. The impact of torrential rain on Andhra Pradesh was altogether more devastating. More than 40 people were killed and there were reports of massive damage to crops and infrastructure. Bangalore, 350 km away, recorded nearly four inches of unseasonal rain, and the skies were cloudy over Ahmedabad, over 1,000 km away. So for a small cyclone, its impact was felt far and wide.

Few things in this world are more discussed than the weather and the climate, more so in this period of global warming. Of all the acts of God, extreme weather is the one thing impossible to guard against. Earthquakes and volcanic eruptions can cause immense damage (as the Boxing Day tsunami of 2004 proves) but it is cyclones, hurricanes and typhoons that cause the most destruction, more often and more regularly than any other climatic event.

Cyclone Bhola (1970), which hit (then) East Pakistan and West Bengal is described as the worst natural disaster of the 20th century. It took three lakh to five lakh lives, the majority in East Pakistan.

Not surprisingly, the Bay of Bengal is considered the birth place of the deadliest storms on record. The 1999 Cyclone 05B, also known as the Paradip cyclone, is probably the worst ever recorded, with a minimum pressure of 912 millibars. It was characterised as a Category Five storm, with maximum wind speeds of 260 kph against Nilam’s 100 kph. The storm surge was recorded at 8 metres (26 feet), against Nilam’s one metre. As the cyclone hit a couple of kilometres off Orissa’s Paradip port, it brought along a wall of water 26 feet high, which travelled up to 20 km inland in some places, inundating entire taluks and killing thousands of people (estimates vary from 10,000 to 50,000). In one place, Padmapur, a third of the residents were killed in the storm. Only two higher storm surges have ever been recorded, the Calcutta cyclone of 1864 (40 feet high) and the Backergunge cyclone of 1876 (30 to 40 feet). It was, in fact, a double whammy for Orissa as the state had been battered, a couple of weeks earlier, by a Category Four storm. Five million farmers lost their livelihood as a result. This was a super-cyclonic storm, a relatively rare event, as most are lower category events. For instance, Bhola was only a Category Three storm, but the destruction was so great because there were hardly any preventive measures. Since then, governments have become more active about early warning and evacuation and the Meteorological Department keeps a much closer eye on cyclones in the monsoon season. It should be remembered that the public normally hears only about storms that threaten inhabited areas as every monsoon season has its quota of storms. There could well be cyclones in the remote corners of the Bay that no one hears about because they pose no threat to humans.

A cyclone is a storm system with a low-pressure centre (the eye) characterised by high winds rotating about a calm centre that produces extremely heavy rain and gale force winds that can reach up to 300 kph in the worst cases. It is often of vast extent and the centre moves onward, often with a velocity of twenty or thirty miles an hour. The destruction it can cause is awesome and the consequences incalculable. Bhola, for instance, is said to have led eventually to the dismemberment of Pakistan. The Yahya Khan regime was accused of callous disregard for its eastern wing. In the subsequent national election, Islamabad’s indifference was a major plank of the Mujibur Rehman-led Awami League’s campaign. It won 167 of the 169 seats in East Pakistan. The rest is history.

Closer to our time, Sandy is said to have shown Americans how a federal government is necessary and irreplaceable; indeed Republican party supporters kept saying after Mitt Romney’s defeat that Sandy was a key factor in that result.

Cyclones are destructive events, but they are a necessary part of the globe’s systems of equilibrium. For instance, they can relieve drought conditions. Perennially water-starved Chennai has been helped more than once by a cyclone that replenished reservoirs and water tables. On a planetary scale, tropical cyclones carry heat energy from the tropics towards temperate latitudes, which makes them an important part of the global atmospheric circulation mechanism. As a result, they help to maintain equilibrium in the troposphere, and to maintain a relatively stable and warm temperature worldwide. Like all things natural, a cyclone too has it function to perform and is essential to the earth’s health even if its inhabitants suffer.

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