Context: The National Crisis Management Committee (NCMC) under the chairmanship of Cabinet Secretary met for the second time to review the preparedness of States and Central Ministries/Agencies to deal with the Super Cyclonic Storm ‘AMPHAN’.
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- The India Meteorological Department (IMD) has informed that the Super Cyclone is expected to reach the West Bengal coast in the afternoon/evening of 20th May with wind speeds ranging up to 155-165 kmph gusting to 185 kmph.
- It will cause heavy rainfall, accompanied by squally winds and storm surges, in the coastal districts of the State.
- The storm is likely to impact the coastal districts -
- Jagatsinghpur, Kendrapara, Bhadrak, Jajpur and Balasore in Odisha and
- East Medinipur, South & North 24 Parganas, Howrah, Hooghly, and Kolkata in West Bengal.
- The storm system in the Bay of Bengal, Amphan, developed into a super cyclone and is expected to make landfall along the West Bengal-Bangladesh coast .
- From 1965 to 2017, the Bay of Bengal and the Arabian Sea collectively registered 46 ‘severe cyclonic storms’.
- Cyclone Phailin in 2013 and the super cyclone of 1999 — both of which hit coastal Odisha — have been the most powerful cyclones in the Bay of Bengal in the past two decades in terms of wind speed.
- By the time it makes landfall in West Bengal, Amphan is expected to tone down into a category 4 Extremely Severe Cyclonic (ESC) storm with wind speed of 165-175 kmph and gusting to 195 kmph.
- Last year, Fani, which was an ESC made landfall in Odisha and ravaged the State, claiming at least 40 lives.
- Before Fani, only one of them (in 1966) had actually made landfall over India.
Likely Impact of Cyclone:
- Amphan is expected to bring “heavy to extremely heavy rainfall” over Gangetic West Bengal and heavy to very heavy rainfall over north coastal Odisha .
- Storm surge of about 4-6 meters above astronomical tide is likely to inundate low lying areas of the coastal regions.
- “Extensive damage to all types of kutcha houses, some damage to old badly-managed pucca structures.
- Potential threat from flying objects, extensive uprooting of communication and power poles,
- Disruption of rail/road link, extensive damage to standing crops, plantations, orchards etc.
Cyclone and Lockdown:
- Cyclones gain their energy from the heat and moisture generated from warm ocean surfaces.
- This year, the BoB (Bay of Bengal) has posted record summer temperatures, a fall-out, as researchers have warned, of global warming from fossil fuel emissions that has been heating up oceans.
- Some of the buoys have registered maximum surface temperatures of 32-34°C consecutively, for the first two weeks of May.
- Cyclone Amphan intensified from a category-1 cyclone to category-5 in 18 hours, an unusually quick evolution.
- Last year Fani, a category 4 cyclone, which swept through the Odisha coast, was again fuelled by high temperatures in the BoB.
- Another researcher said the elevated ocean temperatures this year could, in part, be explained by the lockdown.
- Reduced particulate matter emissions during the lockdown meant fewer aerosols, such as black carbon, that are known to reflect sunlight and heat away from the surface.
- Every year, increased particulate pollution from the Indo-Gangetic plains is transported towards the BoB and this also influences the formation of clouds over the ocean.
- Fewer clouds and more heat in the Bay of Bengal may have amplified the strength of the cyclone.
- Researchers have observed that during the lockdown from March-April, BoB temperatures have been 1-3°C higher than normal. But the exact contribution from aerosols is still to be determined.
- NDRF (National Disaster Management Force) has deployed 26 teams in Odisha and West Bengal and additional teams are enroute to these States.
- The teams are equipped with boats, tree cutters, telecom equipment etc.
- Rescue and relief teams of the Army and Navy alongwith ships and aircrafts of the Navy, Air Force and Coast Guard have been put on standby.
- All necessary measures are taken to complete evacuation of people from low lying areas in cyclone path and maintain adequate quantities of essential supplies such as food, drinking water and medicines etc.
- Police officials have started announcements in the low lying coastal areas of the State, particularly the low lying Sunderbans and areas closer to Digha in Purba Medinipur asking people to leave mud houses and move to safer places.
- Fishing had already been suspended because of lockdown.
- Agencies are directed to prevent disruptions to Power and Telecommunications services.
- Free facility of targeted SMSs to warn the people of the cyclone and intra circle roaming is to be provided.
States now have three types of crisis in front of them — COVID, the cyclone, and migrants returning home.
National Crisis Management Committee:
- It is a committee set up by the Government of India in the wake of a natural calamity for effective coordination and implementation of relief measures and operations.
- It is headed by the Cabinet Secretary.
- A National Crisis Management Committee(NCMC) has been constituted in the Cabinet Secretariat.
- The composition of the Committee is as under:-
- Cabinet Secretary - Chairman
- Secretary to Prime Minister Member
- Secretary (MHA) Member
- Secretary (MCD) Member
- Director (IB) Member
- Secretary (R&AW) Member
- Secretary (Agri & Coop.) Co-opted Member
- An officer of the Cabinet Secretariat as Convenor
- When a situation is to be handled also by the NCMC, it will give such directions to the Crisis Management Group of the Ministry as deemed necessary.
- The Secretary(A&C) will be responsible for ensuring that all developments are brought to the notice of the NCMC promptly.
- In the absence of such a Cabinet Committee, all matters relating to relief shall be reported to the Cabinet Secretary.
Tropical cyclones are developed in the regions between the Tropics of Capricorn and Cancer.
They are caused by atmospheric disturbances around a low-pressure area distinguished by swift and often destructive air circulation.
- It requires warm ocean waters of at least 26.5°C [80°F]) throughout a sufficient depth, at least on the order of 50 m which is necessary to fuel the heat engine of the tropical cyclone.
- They need to form at least five degrees of latitude away from the equator because Coriolis force that is required for cyclones rotation is absent at equators.
- During a tropical cyclone, the Coriolis force deflects winds blowing towards the low-pressure center of the storm and creates circulation.
- They require low wind shear to form.
- Wind shear is the change in wind speed or direction with height in the atmosphere.
- High wind shear will slow spinning cyclones down and prevent them from lasting a long time.
- High relative humidity in the atmosphere up to a height of about 5,000 metres is required.
- Atmospheric instability that encourages the formation of massive vertical cumulus clouds due to condensation of rising moist air.
- In the China Sea and Pacific Ocean, they are known as typhoons;
- In the Caribbean Sea and Atlantic Ocean, they are known as hurricanes
- In north-western Australia they are known as willy-willies and
- In Indian Ocean they are known as tropical cyclones.
Reason for more Cyclones in Bay of Bengal than Arabian Sea
- Bay of Bengal has higher surface temperature in comparison and tropical cyclones need a higher temperature for cyclone genesis.
- In addition, the Bay receives higher rainfall and constant inflow of fresh water from the Ganga and Brahmaputra rivers.
- This means that the Bay’s surface water keeps getting refreshed, making it impossible for the warm water to mix with the cooler water below, making it ideal for a depression.
- Cyclones of low intensity also come from the foreign sources.
- Neighboring Pacific Ocean seas are more prone to cyclones.
- Typhoons originating near the Philippines, China, Thailand and Malaysia enter the Andaman Sea of Bay of Bengal after they weaken in their native regions.
- Coastal region of east is of low topography in comparison to Western areas with Ghats of high elevation.
- Most of the cyclones in the Arabian Sea are local. They collapse a little after making landfall as there is no back-up supply.
- Cyclones usually weaken if they encounter a large landmass.
- However, due to the lack of any such presence between the Pacific and the Bay, cyclonic winds easily move into the Bay of Bengal.
- Once here, the winds encounter the Western Ghats and the Himalayas, either becoming weak or getting blocked in the Bay, but never reaching the Arabian Sea.