Bay of Bengal Current Affairs - 2020

Rapid Intensification made AMPHAN a Super Cyclone

The Cyclone ‘Amphan’ has intensified from a severe cyclonic storm to a Super Cyclone. This has happened in less than 40 hours.

Highlights

The rapid intensification of Amphan into a Super Cyclone is mainly because of rapid warming up of Bay of Bengal. The following are the main reasons that led to rapid intensification of the cyclone

  • High Sea Surface Temperature
  • Enough Moisture in the middle layers of the atmosphere
  • Low Vertical Shear Winds

When does Rapid Intensification occur?

Rapid Intensification of a cyclone occurs when there is increase of sustained winds that blow at a speed of 55 km/hr. Rapid Intensification is common in case of hurricanes, so far not in case of cyclones.

Difference between hurricanes and cyclones

Both hurricanes and cyclones are tropical cyclones. They are named differently based on their region of formation. Cyclones are formed in South Pacific and Indian Oceans. On the other hand, hurricanes are formed in North Atlantic, Eastern and Central Pacific Oceans.

History

Scientists believe that Rapid Intensification might become common among the cyclones in the future. Earlier, Rapid Intensification was observed in cyclone Vayu. However, the main issue is that there is lack of data about rapid intensification rates of cyclone in India.

The two other major Super Cyclones that hit India were Cyclone Gonu in 2007 and Cyclone Kyarr in 2019.

Amphan develops into a super cyclonic storm

On May 18, 2020, Amphan turned into a super cyclonic storm. This is the second super cyclonic storm faced by India since Fani in 1999.

Highlights

The Super Cyclonic storm will hit the coast of Odisha and West Bengal according to the Indian Meteorological Department. The National Disaster Response Force (NDRF) is preparing evacuation plan and response preparedness.

The storm will cause extensive damage upon landfall. The waves are expected to reach a height of 4 to 6 metres. The warnings about a cyclone are given by the Indian Meteorological Department.

Stages of Cyclone Warning System in India

There are five stages of Cyclone Warning System in India. They are as follows

  • Pre-Cyclone Watch
  • Cyclone Alert
  • Cyclone Warning
  • Post Landfall Outlook
Pre-Cyclone Watch

Under this stage, warnings are issued before 72 hours. Th warning under this stage is issued by Director General of Meteorology himself.

Cyclone Alert

This is the second stage in the warning system. The warnings in this stage are issued before 48 hours in advance of the adverse weather over coastal areas.

Cyclone Warning

At this stage, the warnings are issued at least 24 hours in advance of adverse weather conditions.

Post Landfall Outlook

This is issued at least 12 hours in advance of the expected landfall.

Arabian Sea Cyclones are Weak as compared to Bay of Bengal Cyclones

The absence of landmass between the Pacific Ocean and Bay of Bengal, allows the cyclonic winds to move easily into the Bay of Bengal. This makes them stronger than those formed in Arabian Sea.