‘Super cyclone’ to calm down as ‘depression’ by Thursday

Vibha Sharma

Tribune News Service

New Delhi, May 20

The first ‘Super Cyclone’ of the century, Amphan on Wednesday barrelled along the Odisha coast and slammed West Bengal–Bangladesh coasts as an ‘Extremely Severe Cyclone’ with a speed of 155-165 kmph gusting to 185 kmph in a landing process spanning around four hours, according to the IMD. 

Like its beginning as a ‘depression’, Amphan is expected to calm / settle down as one around by tomorrow following the same procedure in reverse as it went through to achieve the status of ‘Super Cyclone’.  It will turn into a ‘Very Severe Cyclone’, then a ‘Severe Cyclone’, a ‘Cyclone/Deep Depression” and end as a ‘Depression’ speeding between 30 to 40 kmph, gusting to 50 kmph, says the weather office 

Starting as a ‘low pressure area’ in the South Andaman Sea, Amphan became a ‘cyclonic circulation’ and turned into a ‘Depression’ around May 15/ 16.  It rapidly gained in intensity due to prevailing conducive factors due to conducive circumstances, says Mahesh Palawat of private forecaster Skymet.

“Seas Surface Temperatures were high and the Vertical Wind Shear was low. The two factors actively contributed to Amphan gaining strength while it made its way up in the Bay of Bengal. SSTs remained high till the time it reached northern parts of the Bay,” he said.

Incidentally, low pressure areas have been forming in the region since the beginning of May.

Cyclone Fani last year and Phailin (the most intense cyclone after the 1999 Odisha ‘Super Cyclone’) in 2013 were also classified as ‘Extremely Severe’ cyclones. 

Experts are relating Amphan’s high intensity to global warming and abnormally warm SSTs in the Indian Ocean. Just like a rocket is powered by hydrogen and oxygen, cyclones/hurricanes are powered by water vapour. More global heating means more water vapour and more power to the cyclones. Indian Ocean is warm ocean. Water is the first and perhaps the key ingredient for the formation of tropical cyclones, they say.

‘Super Cyclone’ is the highest category of tropical storms, beginning with a ‘Depression’, ‘Cyclone/Deep Depression’, ‘Severe Cyclone’, ‘Very Severe Cyclone’ and ‘Extremely Severe Cyclone’. 

Hot-dry weather in Northwest

Drawing all moisture towards it, Amphan has also impacted the weather over Northwest in a way. The prevailing hot and dry weather in the region is due to the absence of easterly winds, Palawat said, predicting that heat wave like conditions to develop over the region “soon”.