Asani to intensify into ‘severe’ cyclonic storm today; Odisha, Bengal on alert

• According to Indian Meterological Department, Cyclone Asani, which developed over southeast regions of Bay of Bengal, will intensify into a ‘severe cyclone’ by Monday.
• The storm will reach close to the Andhra Pradesh-Odisha coast by Tuesday.
• It is unlikely to make a landfall and it could skirt the coastal districts of these states in the next two days.

Intensity of cyclone

• If realised, cyclone Asani could have similarities like cyclone Jawad that developed in the Bay of Bengal and swerved past close to south Odisha in December last year.
• Cyclone Asani rapidly intensified while at sea over the past two days.
• The storm had intensified into the ‘severe’ category after moving at a speed of 14 km per hour.

Location:

• 610 km northwest of Car Nicobar
• 500 km west of Port Blair
• 810 km southeast of Visakhapatnam
• 880 km south-southeast of Puri.

Progression

• It is very likely to continue to move northwestwards till Tuesday evening and reach west-central and adjoining Northwest Bay of Bengal region, off north Andhra Pradesh and Odisha coasts by Tuesday.
• Odisha has been put on a high alert ahead of the heavy rain (64.4mm to 115.5mm in 24 hours) forecast on Tuesday and Wednesday.
• Under the influence of the system in the Bay of Bengal, thunderstorms, lightning and light rain is forecast over Bihar, Jharkhand, West Bengal and Sikkim till May 12.

Tropical Cyclones

• Tropical cyclones are violent storms that originate over oceans in tropical areas and move over to the coastal areas bringing about large-scale destruction due to violent winds (squalls), very heavy rainfall (torrential rainfall), and storm surge.
• They are irregular wind movements involving the closed circulation of air around a low-pressure center.
• This closed air circulation (whirling motion) is a result of rapid upward movement of the hot air which is subjected to Coriolis force.
• The low pressure at the center is responsible for the wind speeds.
• The cyclonic wind movements are anti-clockwise in the northern hemisphere and clockwise in the southern hemisphere (This is due to Coriolis force).
• The cyclones are often characterized by the existence of an anticyclone between two cyclones.
• Tropical cyclones occur around the equator at 5 ° – 30 °, but also have varying names depending upon where in the world they form.
• An average tropical cyclone can travel about 300 to 400 miles a day, or about 3,000 miles before it dies out.

Conditions Favorable for Tropical Cyclone Formation

• Large sea surface with a temperature higher than 27° C,
• Presence of the Coriolis force enough to create a cyclonic vortex,
• Small variations in the vertical wind speed,
• A pre-existing weak low-pressure area or low-level-cyclonic circulation,
• Upper divergence above the sea level system,

Why cyclones occur mostly in late summers?

• Whirling motion is enhanced when the doldrums (region within ITCZ) over oceans are farthest from the equator.
• This happens during the autumnal equinox (August-September).
• At this time, there are two advantages—the air is overheated and the sun is exactly over the equator.

Exam Track

Prelims Takeaway

• Cyclone formation
• Naming of cyclone

Mains Track

Q. What do you understand by tropical cyclones and how are they formed? Also examine the impact of these cyclones on India. (250 words)